Help needed with the water chemistry

[dmcmillen]

I have a simple Dual-Malt porter I am getting ready to brew. It calls for 6.25# Maris Otter (3L) and 3.6875# Brown Malt (65L), 3.75gal mash water. My existing water profile is Alk 98, Bicarb 119, SO4 9, Cl 4, Na 28, Ca 9, Mg 4. Bru'n Water estimates pH at 5.18 with no dilution; dilution, of course will only lower the pH further by reducing the existing alkalinity.

My dilemma is that I want to raise the pH to around 5.4 which will require more baking soda but I also would like to raise my Ca, Cl and SO4 levels which lower the pH. I thought you didn't want to do both at the same time.

Also I was planning on a test mash using scaled down amounts of the grain and water additions, but now I'm not sure what to do. If I stick to AJ's priorities in his Primer sticky, then maybe I should just do what is necessary to hit the pH and not worry about mineral levels but that doesn't feel right.

I must say that for me this water chemistry has been one of the most daunting things I've ever done as a brewer.

 

[ajdelange]

There are several things you could do. This is just one of them. Zero the alkalinity of enough of your your water to make several test mashes by adding (carefully) enough lactic acid to bring the pH to 5.4 (your target). Now add as much calcium salts as you want to get Ca, SO4 and Cl about where you want them. Do a test mash with this water and record pH. Presumably the pH will be low. Use Brewers Friend (it is aware that the alkalinity of bicarbonate depends on mash pH; Bru'n water is not) to tell you how much bicarbonate to add were you to be brewing this with water with 0 alkalinity. Scale that to test mash size, add that much bicarbonate to the test mash water volume and repeat the test mash. You will, presumably, get a pH for this second test mash that is higher than what you got on the first mash but may still not be exactly 5.4. Use linear interpolation to estimate the amount of bicarbonate that would be required to get you to 5.4. Scale this to 1 liter. That's the amount of bicarbonate you would have to add to each liter of water with the desired calcium and stylistic ion content but no bicarbonate. Subtract 119 mg from that because each liter of your water contains 119 mg of bicarbonate already. The difference between what you need and 119 (what you have) is the amount of bicarbonate you will need to add to each liter of your water.

Yes, for someone starting out the chemistry of brewing water is quite daunting. It is actually quite simple once you grasp the basic concepts of acid base chemistry on which it is built, especially if that is presented in a particular way that is very handy for brewing problems. I must say it took me a long time to get it but then that basic chemistry is not in TNCJHB.

 

[dmcmillen]

Thanks AJ. Probably going to vent a bit here, so please take with a grain of salt. Is this situation due to the particular grain bill? I keep thinking I am getting a grasp on the overall tenets of water chemistry. I expected that the the initial pH of this mash would be on the high side and require acidification because both grains are base (not roasted) and my untreated water source is alkaline. So I was surprised when the suggested pH came in on the low side. (Kai's Brewer's Friend comes in even lower at 4.63). I'm looking forward and wondering if I am going to have to do this with every brew and wondering if it's worth the time and effort (just frustrated right now). I don't mind doing a test mash or two the day before. I had expected to take the spreadsheets recommendations into the test mash and then scale up the adjustments for brew day.

I've been brewing a long time and wanted to take my brewing to the next level. I have had 3 brews so far treating my water. The first was ok, but I had never brewed it before. The 2nd is a recipe I have brewed many times and everyone loves that beer, a Vanilla Porter which turned out very flat and one dimensional and is almost a throw away. The 3rd, brewed probably a hundred times, a Chili beer that I have won a local award for, is ready to be tapped. Bottom line, not enough data points and those that I have I'm not sure what I have learned. Part of the problem was that I didn't really know how to adjust on the fly and you have helped me understand how to do that.

Now add as much calcium salts as you want to get Ca, SO4 and Cl about where you want them.

How do I calculate the number of grams of a mineral for a particular volume of water. E.g., Ca where I'm looking for say 60ppm (is that per ml??).

Use Brewers Friend (it is aware that the alkalinity of bicarbonate depends on mash pH; Bru'n water is not) to tell you how much bicarbonate to add were you to be brewing this with water with 0 alkalinity.

Can I just calculate the amount of sodium bicarbonate based on the pH shift needed. I.e., assuming a buffering capacity of 40mEq / kg malt, and 1 mmol sodium bicarb absorbs 1mEq protons, and 1 mmol sodium bicarb = 84 mg, if we needed to shift pH by .1 then we would need .1 * 40 * 84 = 336 mg/kg malt.

 

[ajdelange]

I expected that the the initial pH of this mash would be on the high side and require acidification because both grains are base (not roasted) and my untreated water source is alkaline. So I was surprised when the suggested pH came in on the low side. (Kai's Brewer's Friend comes in even lower at 4.63).

Something is definitely fishy here. I measured a sample of MO at a DI mash pH of 5.69 with a linear buffering coefficient of -48.6. It's going to take about 41.5 mEq of protons to get 6.5 lbs of that to a mash pH of 5.4 Assuming that you are mashing with 3.5 gal. of your water with alkalinity of 1.96 mEq/L you will need about 22.7 mEq more acid to get the water to pH 5.4. That's a total of 64.2 mEq. For you to require any bicarbonate (or other alkali) the 3.6875 lbs of brown malt would have to have acidity, WRT 5.4, or more than that. I don't know anything about brown malt but if I assume it is something like the 60 L crystal than Kai measured way back when it would provide 60 mEq of acid which means you actually would need 4 mEq more acid (perhaps supplied by the calcium reaction) but should be pretty close to the 5.4 mark. Were it like the 80 L crystal I measured (pHdI = 78, first buffering coefficient = -89) then you would need only 17 mEq alkalinity to hit pH 5.4. Now these aren't even really guesses as to what actual mash pH might be but I am suspicious of a mash pH estimate as low as 4.6 using a malt with color of 65 L.

I'm looking forward and wondering if I am going to have to do this with every brew and wondering if it's worth the time and effort (just frustrated right now).

If you want to understand why you are getting what you get then yes, at least initially, you do have to take lots of measurements and do calculations but, as you are well aware, many don't bother and still make passable beer.

I don't mind doing a test mash or two the day before.

With an unusual malt like this brown malt I think the test mashes are especially useful.

I had expected to take the spreadsheets recommendations into the test mash and then scale up the adjustments for brew day.

Spreadsheets can be used that way but only after you have 'calibrated' them by what you find through experiment, measurement and experience. You can't expect them to be that accurate the first time you encounter them.

How do I calculate the number of grams of a mineral for a particular volume of water. E.g., Ca where I'm looking for say 60ppm (is that per ml??).

You can rely on a spreadsheet to be reliable with respect to those calculations. It's very straight forward. CaCl2 contains (per mole) 1 mole of calcium and 2 moles of chlorine. You can look up the molecular weights of calcium and chlorine (half the molecular weight of chlorine gas, Cl2) and figure out what the percentage by weight of each atom is in the salts that contain it. ppm means parts per million or milligram per liter.

Can I just calculate the amount of sodium bicarbonate based on the pH shift needed. I.e., assuming a buffering capacity of 40mEq / kg malt, and 1 mmol sodium bicarb absorbs 1mEq protons, and 1 mmol sodium bicarb = 84 mg, if we needed to shift pH by .1 then we would need .1 * 40 * 84 = 336 mg/kg malt.

Yes, you could do that but consider two things:
A) As pointed out at https://www.homebrewtalk.com/forum/threads/help-needed-with-the-water-chemistry.648956/#post-8280356, 1 mmol of bicarbonate absorbs a little less than 1 mEq of protons. As noted Brewr's Friend is aware of this so if you want to use it to do the calculation you will be OK. The curve below shows the number of protons a mmol (84 mg) of sodium bicarbonate can absorb. At pH 5.4 this is about 0.91 mEq/mmol. Thus your calculation would need to be increased to .1 * 40 * 84 / 0.91 = 369. Also note that the pH shift from which the bicarbonate addition should be calculated is relative to to what you measured in a test mash - not what a spreadsheet gives you.
B) 40 mEq/kg is a guess at the average linear term buffering coefficient.

Presumably you would do a test and use this calculation to tell you how much bicarbonate to try in a second test mash.

 

[dmcmillen]

Something is definitely fishy here.

Well both Martin's and Kai's spreadsheets are predicting a very low pH (Martin, 5.18)

In Brewer's Friend:

• Using my current water & desired mineral levels predicted pH is 4.54
• Using water of 0 alkalinity and pH of 5.4 & desired mineral levels pH is 4.45
• To move from 4.45 to 5.38 would require 25 grams of NaHCO3, obviously not an option because of the excessive sodium (235) and bicarbonate content.

Now, of course, this is without any testing. I was wondering why you were suggesting testing with water that I zeroed the alkalinity by taking to a pH of 5.4 rather than testing with my current water??

 

[Yooper]

Well both Martin's and Kai's spreadsheets are predicting a very low pH (Martin, 5.18)

In Brewer's Friend:

• Using my current water & desired mineral levels predicted pH is 4.54
• Using water of 0 alkalinity and pH of 5.4 & desired mineral levels pH is 4.45
• To move from 4.45 to 5.38 would require 25 grams of NaHCO3, obviously not an option because of the excessive sodium (235) and bicarbonate content.

Now, of course, this is without any testing. I was wondering why you were suggesting testing with water that I zeroed the alkalinity by taking to a pH of 5.4 rather than testing with my current water??

This makes me question the mineral levels. That drop is really a huge drop, just with the water and minerals. What are you adding?

 

[dmcmillen]

What are you adding?

2.5g Gypsum, 4g CaCl (mash only right now). With my water and no additions prediction is 4.63. As AJ said something seems fishy.

 

[Yooper]

2.5g Gypsum, 4g CaCl (mash only right now). With my water and no additions prediction is 4.63. As AJ said something seems fishy.

Definitely- you can totally ditch the gypsum for a porter, but since it's such a tiny amount it should effect the pH that dramatically.

Have you tried brun'water for the spreadsheet?

 

[dmcmillen]

Definitely- you can totally ditch the gypsum for a porter

This is where I am still uncomfortable with the water chemistry. I know AJ's Primer sticky does not use gypsum for a porter. However, if I am trying to hit some mineral levels for a suggested profile (like a Brown Malty or Brown Balanced, then gypsum is a choice to use to hit those levels. I just don't have a feel for this right now. Seems like I'm trying to hit pH and mineral levels at the same time and it's a bloody moving target. Each time I think I have a feel for the basics I find that the science is a little more complicated than I thought. And, of course, the choices I make are dependent on my personal tastes. I keep trying to dial in a particular chemistry for a brew that I think will suit my tastes for that style, but I keep running into problems like this one.

Have you tried brun'water for the spreadsheet?

Yes. I use primarily Bru'n Water. Bru'n Water predicts a 5.18 using my water. That's what led me to post this. AJ suggested I use Brewer's Friend because of the way it handles alkalinity across the pH range.

 

[Yooper]

This is where I am still uncomfortable with the water chemistry. I know AJ's Primer sticky does not use gypsum for a porter. However, if I am trying to hit some mineral levels for a suggested profile (like a Brown Malty or Brown Balanced, then gypsum is a choice to use to hit those levels. I just don't have a feel for this right now. Seems like I'm trying to hit pH and mineral levels at the same time and it's a bloody moving target. Each time I think I have a feel for the basics I find that the science is a little more complicated than I thought. And, of course, the choices I make are dependent on my personal tastes. I keep trying to dial in a particular chemistry for a brew that I think will suit my tastes for that style, but I keep running into problems like this one.


Yes. I use primarily Bru'n Water. Bru'n Water predicts a 5.18 using my water. That's what led me to post this. AJ suggested I use Brewer's Friend because of the way it handles alkalinity across the pH range.

Hitting a "profile" is something I have an issue with. Think of the salts you're using as salt or seasonings in cooking- some garlic or onion in spaghetti sauce- instead of part of a "profile" for a certain water type.

That small amount of gypsum isn't really doing anything for you, so it doesn't matter if you add it, but it seems to be driving your pH down more than you'd want. Just take it out.

Also, check the way you entered brown malt. If you entered it as a roast malt with a dark color, it could be falsely showing you a low pH.

 

[ajdelange]

Well both Martin's and Kai's spreadsheets are predicting a very low pH (Martin, 5.18)

Using the properties of Maris Otter that I measured, the quantities you specified and assuming that the Brown Malt is linear with coefficient 50 mEq/kg•pH it's diPH would have to be 3.76 in order to give a mash pH of 5.18. Now maybe it is. I really don't know. Note that the dipH of sauermalz is around 3.4 (though it has much higher buffering). Another way of looking at it is that if I substituted 0.68 lb of sauermalz for the brown malt I would get pH 5.18. That's why I think something is funny.

In Brewer's Friend:

• Using my current water & desired mineral levels predicted pH is 4.54

That would require 2.2 pounds of sauermalz.

• Using water of 0 alkalinity and pH of 5.4 & desired mineral levels pH is 4.45

That would require 2.33 lbs of sauermalz.

• To move from 4.45 to 5.38 would require 25 grams of NaHCO3, obviously not an option because of the excessive sodium (235) and bicarbonate content.

Closer to 28 grams in fact but your point is made. Those programs are giving you unreasonable pH estimates unless this brown malt is more like sauermalz than crystal/caramel malt of around the same color.

Now, of course, this is without any testing. I was wondering why you were suggesting testing with water that I zeroed the alkalinity by taking to a pH of 5.4 rather than testing with my current water??

As I indicated in my first response, there are several ways you could go here. I suggested what I did because of what I saw as a need to focus on the grist rather than the water. By zeroing its alkalinity you take it out of the picture. What I would probably recommend rather than that at this point would be to make a test mash on the brown malt by itself with DI water so as to at least get pHDI. I would then recommend a second test with the brown malt and some bicarbonate to get a stab at the buffering.[/QUOTE]

 

[Yooper]

I use three pounds of brown malt in my porter- what brand are you using? That could also make a difference- but like AJ said, a test mash would be the way to go.

 

[ajdelange]

This is where I am still uncomfortable with the water chemistry. I know AJ's Primer sticky does not use gypsum for a porter. However, if I am trying to hit some mineral levels for a suggested profile (like a Brown Malty or Brown Balanced, then gypsum is a choice to use to hit those levels. I just don't have a feel for this right now.

You actually have quite a bit from what I can see but there is more to come. Solving problems is the best way to gain the insight you would like to have.

Seems like I'm trying to hit pH and mineral levels at the same time and it's a bloody moving target.

You are making the assumption that this is possible to do. In most cases it isn't and the best we can get is a closest fit to what we want (or think we want). I echo Yooper's advice to not put too much reliance on profiles. If your realized level of an ion is within 50% of what a profile says you are probably close enough and you will want to tweak for flavor anyway. Note also that the profiles in Bru'n water (I haven't checked any other program) are only possible at pH 8.3.

Each time I think I have a feel for the basics I find that the science is a little more complicated than I thought.

That's where continues dabbling will help you.

And, of course, the choices I make are dependent on my personal tastes.

As they should be! The goal is to please you and your customers - not the author of a spreadsheet.

I keep trying to dial in a particular chemistry for a brew that I think will suit my tastes for that style, but I keep running into problems like this one.

And you will continue to if you continue to place too much reliance on spreadsheets and calculators. They all have limitations especially when it comes to the way they model malts' acid base parameters. Note that this isn't because the guys that put them together are dummies. It's because the only way to do it better is to go out and measure every batch of every malt shipped and that isn't practical unless the maltster does it when he measures other malt parameters and the maltsters haven't expressed much interest in doing that.

AJ suggested I use Brewer's Friend because of the way it handles alkalinity across the pH range.

Just for the record: I recommended Brewer's Friend specifically for sodium bicarbonate additions because it models the bicarbonate ion correctly. Bru'n water does not as of a few weeks ago but I am sure that will be fixed pretty quickly. The error is only about 10% at mash pH anyway.

 

[dmcmillen]

Also, check the way you entered brown malt. If you entered it as a roast malt with a dark color, it could be falsely showing you a low pH

Martin said that although the brown malt is roasted that I should treat as a base malt. Treating it as Roasted lowered the predicted ph to 4.30. Note that the 5.18 (base malt) and the 4.30 (Roasted) were with no salts.

Just for the record: I recommended Brewer's Friend specifically for sodium bicarbonate additions because it models the bicarbonate ion correctly. Bru'n water does not as of a few weeks ago but I am sure that will be fixed pretty quickly. The error is only about 10% at mash pH anyway.

Thanks for the clarification AJ.

I use three pounds of brown malt in my porter- what brand are you using?

Thomas Fawcett, EBC 175-200 (~66-75L). At this point it doesn't really matter since we are only looking at the spreadsheet predictions. They don't know the type, only the color.

What I would probably recommend rather than that at this point would be to make a test mash on the brown malt by itself with DI water so as to at least get pHDI. I would then recommend a second test with the brown malt and some bicarbonate to get a stab at the buffering

Are we assuming that the low prediction is due to the way that the Brown Malt is being considered? I could input any base grain with a 65L color and still get the same results, so I'm wondering what we're learning with respect to this recipe. This maybe a stupid idea, but has anyone thought of asking Martin or Kai why the predictions are so low for this grist bill?

I want to make sure I have this right testing as you suggested with the brown malt. The 1st test I would record the pH. The 2nd test I would add an amount of bicarbonate estimated to shift the pH up say by .1, measure the actual shift. I am still going to need to make another test with both grains and salts.

What I was doing for water chemistry in the past was based on a recommendation of a local brewer here who had a nano-brewery and had the same water that I have. For malty beers add 1/8 to 1/4 tsp CaCl/5gals. For hoppy beers add 1/8 to 1/4 tsp gypsum/5 gals.

 

[ajdelange]

Martin said that although the brown malt is roasted that I should treat as a base malt. Treating it as Roasted lowered the predicted ph to 4.30. Note that the 5.18 (base malt) and the 4.30 (Roasted) were with no salts.

Martin must have some reason for telling you that brown malt is more like a base malt of similar color but that flies in the face of common sense and if it is indeed like base malt then there is no way the predicted pH would be as low as you have been finding. In fact you should find, as you intuited, that acid would be required rather than alkali. If you are getting pH's as low 5.18 with two base malts entered with alkalinity as high as yours that suggests error in data entry.

Are we assuming that the low prediction is due to the way that the Brown Malt is being considered? I could input any base grain with a 65L color and still get the same results, so I'm wondering what we're learning with respect to this recipe.

You have hit upon the basic shortcoming of this (the spread sheets') method of mash pH prediction. It assumes that a malt's titration 'curve' (they assume it is linear - as we shall see in a moment it isn't) is predictable from its color or type. In fact there is quite a bit of variability in the parameters of malts of similar color and/or type.

This maybe a stupid idea, but has anyone thought of asking Martin or Kai why the predictions are so low for this grist bill?

The answer is that the prediction are as low as they are because of the data you are feeding the programs. What you are getting does not seem to make sense in terms of what we expect from these programs and so we suspect you may be entering something in error.

I want to make sure I have this right testing as you suggested with the brown malt. The 1st test I would record the pH.

Let's assume that the malt has identical properties to the 80L Briess malt that I measured. In your first measurement you mix a kg of it with 2L of mash temperature DI water (you wouldn't need to use nearly this much but let's keep the math easy here), let it sit for 20 minutes, pull off a sample of the liquid, let it cool to room temperature and measure the pH. It would be 4.77.

The 2nd test I would add an amount of bicarbonate estimated to shift the pH up say by .1, measure the actual shift.

For the second test you note that with this low DI mash pH that the malt is pretty acidic and so decide to add a gram NaHCO3 to another 2 L of DI water and mash another kg of the malt using the same procedure. Again you don't need that much malt or water in reality. This time you get a pH of 4.90. A gram of NaHCO3 is 1000/84 = 11.9048 mmol and by consulting the curve in the earlier post you see that at pH 4.90 each mmol of bicarbonate absorbs 0.967948 mEq protons (you can't read that accurately from the curve, of course, thus I am using calculated values) so that you have absorbed 11.9048*0.967948 = 11.5232 mEq protons. You would then calculate (11.5232)/(4.77 -4.90) = -88.64 and realize that this malt has, ostensibly, more buffering capacity than the 'average' malt.

Your next step would be to plot the measurements you have made on a graph. You don't have to do this because you can do the extrapolation to target pH without it. The model is mEq/kg = -88.64*(pH - 4.77). The bicarbonate estimate for pH 5.4 is simply -88.64*(5.4 - 4.77) = -55.8432 mEq/kg. The - sign simply indicates that this is the quantity of protons that must be absorbed. The bicarbonate required is then 88.64*(5.4 - 4.77)/0.9052 = 61.6916 mmol/kg as each mmol of bicarb supplies 0.9062 mEq of proton absorbing capacity at pH 5.4. The plot will certainly aid in your understanding. It will look like this:

The solid dots at the left are the results of the two measurements and the thin red line is and extension of the line connecting the dots. The open rectangle is the point on that extrapolating line at pH 5.4 which is a reasonable target pH. The heavy blue line is the actual titration curve from this malt which, as is plain, is not linear. Whereas the linear extrapolation would cause you to conclude that you need to absorb about 55 mEq protons per kg of this malt in fact you need to absorb only about 47. This illustrates another problem with the basic spreadsheets. They must assume linearity as without it they would have to use recursive techniques to get pH estimates. The problem rears its head when DI mash pH is distant from the target pH. Fortunately this is only the case with specialty malts which tend to be used in smaller quantities than the base malts whose DI pH's tend to be within a couple of tenths of target pH.

I am still going to need to make another test with both grains and salts.

Clearly in the case of this malt (and we are not suggesting that it is necessarily a good example to use when discussing Brown Malt) another measurement is warranted. On the plot we show that a 3rd measurement with 4 grams of NaHCO3 would get us closer to target pH. With that third measurement in hand we can either
1)Throw away the second measurement and do a linear extrapolation using the first and third measurements. This gets us a required absorption estimate which is within half a mEq/kg of the actual
2)Fit a quadratic to the three measurements thus getting a model for this malt that includes its non linearity.

At this point you are probably thinking that this is a lot of work and most people aren't interested in understanding the underlying science to the point where they can practically use information like that which we have illustrated here. Even if you get detailed data on a library of malts there is no place to take it unless you put together your own spreadsheet (which is actually very easy to do if you understand the science the hard part of which is the bicarbonate chemistry).

In your case I think I'd at least do the DI test mash on the Brown Malt to see if it is unusually acidic. If it turns out to be then I would doubtless make additional measurements. If not then a test mash or two with your actual brewing water would be the way I'd go.

What I was doing for water chemistry in the past was based on a recommendation of a local brewer here who had a nano-brewery and had the same water that I have. For malty beers add 1/8 to 1/4 tsp CaCl/5gals. For hoppy beers add 1/8 to 1/4 tsp gypsum/5 gals.

I, in essence, do exactly that but use RO water as the base.

 

[mabrungard]

I have brewed with Crisp brown malt and it does generally fall in line with the acidity of base malt vs color curves that I've developed. That acidity is lower than that of roasted grains. It is unlikely that brown malt would have the acidity of roast grains since its not kilned that strongly. With the quantity of brown malt in that recipe, the pH would be much lower than 5.1 if a 'roast' setting was used in Bru'n Water.

With that said, I have had a user in Britain mention that there is an British Amber malt that is reputed by the maltster to be a 'roast' grain. When that user brewed with a portion of that amber malt, he did report a lower than expected pH. That difference between prediction and measurement was much smaller if the amber malt was entered as 'roast'. So this confirms that you can't rely on color to guide you solely with respect to malt acidity. Fortunately, these 'outliers' are typically employed at low percentage in a grist and their impact on pH is lower.

 

[ajdelange]

It is unlikely that brown malt would have the acidity of roast grains since its not kilned that strongly.

Then where does the color come from? IIRC in days or yore malt was kilned directly over the fire which imparted the color but I thought that today concern over nitrosamines would have ended that.

 

[dmcmillen]

If you are getting pH's as low 5.18 with two base malts entered with alkalinity as high as yours that suggests error in data entry.

What you are getting does not seem to make sense in terms of what we expect from these programs and so we suspect you may be entering something in error.

The answer is that the prediction are as low as they are because of the data you are feeding the programs. What you are getting does not seem to make sense in terms of what we expect from these programs and so we suspect you may be entering something in error.

The fact that I am seeing a low pH prediction from two different spreadsheets would certainly make that a logical conclusion, one I would come to as well. Of course the other possibility is that there is some sort of bug in the spreadsheet logic. I have checked and double checked my input and don't see any errors. That's why I zeroed any salt additions. The water and grain bills are correct. I will go away from for a while and come back with a fresh mind to double check again. I just don't see an input error. I'm at a loss.

The point I was trying to make about the focus on the Brown Malt is that the spreadsheets don't know I have a Brown Malt. All they know is that I have 6.25# of a base grain with a 3L (that I happen to call Maris Otter) and 3.6875# of a base grain with a 65L (that I happen to call Brown Malt). I am assuming that the spreadsheet only uses the type, amount and color in the calculations.

Now as AJ has helped me understand I am only looking for a spreadsheet to provide me with a general starting point that I take to the test mash and help with the mineral calcs; I now see that shooting for a particular "profile" is probably not a good idea. This time the starting point didn't make any sense which lead to my posting this. Nothing like a trial-by-fire education. I think I've run the emotional gambit from confusion to frustration to acceptance, probably compounded by my original and wrong assumption that this is an exact science and the spreadsheets were there to plug the numbers into and wallah, out spit the numbers I would expect to see.

 

[brew_darrymore]

Can you post a screenshot of the Water Report Input tab of Brunwater?

 

[Silver_Is_Money]

I just checked my data received from Breiss, and within the limited data released to me their lowest DI pH measured among all of their malts was 4.20 for an extremely dark and obscure (as in not apparently available at retail) crystal malt. Their lowest generally available at retail caramel/crystal malt DI mash pH was 4.51. The lowest DI pH seen among any/all of their various dark roasted malts was 4.24, and most selections within this category did not closely approach this low of a DI mash pH. Their lowest DI mash pH for what they classify as a "kilned" malt as seen in data released to me was 4.93, but admittedly this malt did not dip into the typical Lovibond color range seen for "brown" malts.

I'm shocked that Brewer's Friend would predict a mash pH of 4.54, as it generally yields higher results that are typically more overall ballpark in line with what I see for my own mash pH program.

 

[dmcmillen]

Ok, I have carefully reviewed all input in Bru'n Water and Brewer's Friend and see no data input errors. Bru'n water predicts 5.18 with existing water and no salt additions. Brewers Friend predicts 4.63 with same input. I am including screen shots for Bru'n Water so please review and let me know if you see any problems.

As soon as I can squeeze out some time if will do test mashes.

 

[Silver_Is_Money]

For your grist to mash at pH 5.18 would in my opinion require that the DI_mash pH of specifically the brown malt is close to 4.00 or perhaps a tad lower than this. If however your brown malts DI_mash pH falls between the ranges of 4.5 and 5.0, then (given your mash water with no additional mineralization, and with its rather high alkalinity at ~98), in my opinion your overall grist will more likely mash at somewhere between 5.35 and 5.6 pH than to mash at a pH of 5.18. I'm basing my opinion here upon a presumption of the unlikelihood of the brown malt having a DI_mash pH that comes in at ~4.00 or lower.

I would suggest that you perform a DI_mash test upon the brown malt, if not upon both malts. I once asked a well known UK maltster to reveal their DI_Mash pH for their malts, and they were not at all willing to get specific with respect to their individual malts, but they suggested that I initially presume 4.5 to 5.5 to be typical of the overall range of potential possibilities for the aggregate of their malts. I presume that this sets an initial floor for their brown malts DI_mash pH in the general vicinity of pH 4.5. But potentially they were also factoring their crystal malts into this broadly sweeping reply. Therefore, only a DI_mash pH test for the brown malt will resolve this.

Edit: I just realized that A.J. DeLange had already (in a post above) given serious doubt to the low pH that would be required of the brown malt in order for the two component grist to mash at 5.18 in water with alkalinity at ~98.

 

[dmcmillen]

Just finished a test mash on 7oz Brown Malt with 21oz DI water at 150 for 20 mins. Took 3 measurements which were 5.01 @ 20C, 5.13 @ 19.6C, and 5.15 @ 19.4C.

I was planning on doing a 2nd test with some bicarb to determine buffering but ran out of time since this was my first test mash and I was working out the kinks. I heated a larger container with water to 150 and immersed the smaller container with the grain in it for 15mins to warm the grains. Have to put something heavy on it or it floats. I then added 150 strike water to the grains and set the 20 min timer. I had a hell of a time maintaining the mash temp for that small a mash. I ended up having to heat the mash at least twice in the 20 mins. Anyway, just providing this info in case someone has some suggestions as to better the process.

The MW102 meter instructions say that the pH measurement is ready when the hourglass symbol stops blinking. However, my experience has been that the hourglass never blinks but does disappear which I have assumed is when the measurement is ready. Also, the readings continue to change after the hourglass disappears so I have to make sure I press hold to capture the measurement as soon as I see it disappear. Anyone have a MW102 that can comment on this?

 

[Silver_Is_Money]

Out of the box, 'Mash Made Easy' predicts 5.00 as the pH for a 65L "Brown" malt. Thanks for doing this series of DI_mash tests. I now feel far more confident in my chosen pH math model for this somewhat obscure (at least in the USA) class of malts. Of course, 'MME' allows you to override any of its "canned" DI_pH selections, as it permits you to enter your actual measured DI_pH values for all malt/grain entries.

 

[dmcmillen]

AJ, I have a question. At the end of the 20 min test mash I made 3 successive measurements of the same sample and got the 3 results posted above 5.01, 5.13, and 5.15. I calibrated the meter before the test and had done a stabilization test a couple of weeks ago. I'm curious as to why the measurements would be different on the same sample, albeit with slightly different temps.

The other thing I alluded to was my experience with the MW102 continuing to change readings after the hour glass disappears. Manual says when it quits blinking the reading has stabilized. At this point, I am uncomfortable knowing when the reading has stabilized. E.g., which of the 3 readings above to I use, or do I use an avg or mean of the three. I believe I am using it correctly and I am using your procedures in taking the samples.

Also, I only have enough Brown Malt to do two more test mashes. If I do a 2nd to establish buffering (again having to establish the correct first dipH) then I can only do one more test with actual grain bill and salts.

Anyway, would appreciate your thoughts here.

 

[cire]

It's a little out of date, but Table B might help.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/j.2050-0416.1924.tb02620.x

The rest is possibly worth a read too.

 

[ajdelange]

AJ, I have a question. At the end of the 20 min test mash I made 3 successive measurements of the same sample and got the 3 results posted above 5.01, 5.13, and 5.15. I calibrated the meter before the test and had done a stabilization test a couple of weeks ago. I'm curious as to why the measurements would be different on the same sample, albeit with slightly different temps.

Temperature does, of course, have an effect, but other things do too one of which is time. We wait 20 minutes to be sure that the mash pH has stabilized but it does continue to drift beyond that point. Then your probe has to get used to its environment. When you first put it into the sample the junction and bulb are both we with the DI rinse water. It needs to be washed away by the sample and equilibration between both of these needs to take place before you get a steady reading.

The other thing I alluded to was my experience with the MW102 continuing to change readings after the hour glass disappears. Manual says when it quits blinking the reading has stabilized.

I was hoping and MW102 owner would comment on this. When the hour glass goes away that only means that the reading has not changed by some amount in some time period. It does not mean the reading is stable. I wish manufacturers would remove this 'feature' or at least allow the user to disable it. Some manufacturers allow you to set the change threshold and/or time interval. Not sure what the case is with the MW102. In any event the best, IMO, procedure is to insert the probe into the sample and stir. The pH reading will be changing rapidly at this point. After 20 sec or so of stirring stop moving the probe (there is a 'stirring error' effect). Ph should now start to migrate towards equilibrium. When it appears to be stable, stir again. You may well see a small but rapid change while stirring. Stop and hold still again. Repeat a couple of times. When the 'stirring error' is small and post stirring readings are close to the same, record the reading.

At this point, I am uncomfortable knowing when the reading has stabilized. E.g., which of the 3 readings above to I use, or do I use an avg or mean of the three.

I'd toss the 5.01 reading and accept the 5.13 and 5.15 readings. The change of 0.1 between the first and second readings is not unreasonable if you were accepting readings based on the meter's determination. Clearly the pH was not stable even though the meter's algorithm said it was.

There is a bit of art in pH meter use. Keep taking pH measurements and you will get the hang of it.

 

[Silver_Is_Money]

When I placed your recipe into Brewers Friend and chose base malt for both malts and added your water and then allowed it to calculate your mash pH based upon the malts Lovibond colors it delivered a mash pH of 4.62. When I subsequently selected for DI_mash pH based calculations and entered 5.67 for the Maris Otter and 5.1 for the Brown, Brewers Friend delivered a far more sensible and likely recipe and water based mash pH of 5.57. It is clear to me that Brewers Friend can not properly calculate the DI_mash pH for 65L Brown malt based solely upon its Lovibond color, and it unfortunately offers no category other than "base" which makes sense to select for this particular malt class. Since Bru'n Water doesn't reveal to the end user its internal DI_mash pH predictions for grist components (to my knowledge at least) I can only speculate that Bru'n Water appears to perhaps be in a quite similar pickle with respect to its internal handling of the DI_mash pH for specifically Brown malts, only not quite as deeply reflecting such error as does Brewers Friend.

Applying your recipe and water to Mash Made Easy and letting it default to its own internal selections of DI_mash pH (which are 5.67 and 5.0 respectively for 3L Maris Otter pale and 65L Brown) I get a final mash pH of 5.58. Quite similar overall to the 5.57 of Brewers Friend when in DI_pH mode, and nowhere near 5.18 or 4.62 pH.

Note carefully that if you are going to add any calcium/magnesium minerals to your water for the mash, then you should accordingly expect a mash pH of somewhat below the general range of 5.57/5.58. A moderate addition of such mineralization alone should get you to a mash pH which is closer to around 5.4. There should be no need for the addition of baking soda.

 

[ajdelange]

Obviously Brewer's Friend uses Kai's model and I believe Bru'n water does too. Working from memory here but I am visualizing one of the plots in Kai's paper which shows DI pH vs color for the ensemble of malts he measured. It has three groups. The first is base malt. These lie in a tight group near the origin and exhibit a steep pH vs DI slope. The other two groups are the roast malts which exhibit a wide range of color but a narrow range of pHDI and the caramel/crystal group which have a steeper slope than the roast's but a much less steep one than the roasts. Brown malt apparently doesn't fit into any of these groups and it is little wonder, thus, that it is ill modeled by programs that insist on placing it into one of those categories.

I've noted many time before that pH predictions are much more sensitive to error in pHDi than to error in buffering coefficients so that a program that allows one to enter a better pHDI estimate than another, even though it have a crude buffering model such as the three coefficients being -40, 0, and 0, will do appreciably better for a malt, such as this brown malt, that doesn't fit into one of the three categories of Kai's model. Thus we would expect Mash Made Easy to do a better job than Brewer's Friend or Bru'n water now that OP has a pHDI measurement of about 5.15.

 

[Silver_Is_Money]

Thank you A.J., but I was actually making reference to the results derived from Mash Made Easy when in its standard default mode, which is for most users (who do not have the time or wherewithal to perform DI-mash testing) its easiest option to use, and not when it is being used with its option to insert actual DI_mash pH values (which when inserted automatically override the default internally computed DI_mash pH values). The differences in output for this case are however minimal, since the default selection that MME makes for the 65L Brown malt is so close to the measured DI_mash pH test results derived by the OP in his three separate tests.

 

[Silver_Is_Money]

It's a little out of date, but Table B might help.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/j.2050-0416.1924.tb02620.x

The rest is possibly worth a read too.

Old but clearly excellent information here! Thank you kindly for posting this. I have downloaded a copy.

 

[mabrungard]

Bru'n Water does not use DI pH in its calculations. It uses a malt acidity in combination with the alkalinity of the brewing liquor to arrive at a net acidity that is then correlated to a predicted mash pH. That correlation is completely empirical.

I can't see how a DI pH value can reliably be used in the complexly buffered mash system, thus the reason I never considered DI pH in practice.

The argument that pH can't relate what is in a wine like a titratable acidity test can, is the reasoning behind going with the malt acidity approach in Bru'n Water. Its a strong reason why its model seems to be more robust than others. You'll never see a vintner considering pH over TA when assessing the quality and character of their products.

 

[dmcmillen]

There is a bit of art in pH meter use. Keep taking pH measurements and you will get the hang of it.

I think I need to practice taking readings before I do another test mash especially since I only have enough extra Brown Malt for two more tests. Any suggestions as to what I can use to test on that is in the 4 - 7 range. StarSan is around 3. Or I could use the 4 or 7 buffer solution.

 

[Silver_Is_Money]

I think I need to practice taking readings before I do another test mash especially since I only have enough extra Brown Malt for two more tests. Any suggestions as to what I can use to test on that is in the 4 - 7 range. StarSan is around 3. Or I could use the 4 or 7 buffer solution.

Are you hoping for 4 or lower DI_mash pH results for your 65L Brown malt that will justify mashing your recipes grist into your water at a measured pH of 5.18 so as to verify the superiority of the empirical method over that of your actual DI_pH testing? Why not just trust yourself and your pH meter, and accept that the Brown malt is quite likely to actually mash solo in DI Water at a DI_pH of around 5? I'm amazed at how many home-brewers will doubt their pH meter when it does not agree highly with a software based empirical model that (no mater how it is designed) is merely making internal guesses. Granting that the software developer (with myself fully included here) develops math models which are designed to in most cases make what are presumed to be very good guesses, such is clearly not going to be true for all cases, as it appears should quite likely be evident for your 65L Brown malt. A guess should never take preeminence over actual test results.

 

[CadiBrewer]

I think I need to practice taking readings before I do another test mash especially since I only have enough extra Brown Malt for two more tests. Any suggestions as to what I can use to test on that is in the 4 - 7 range. StarSan is around 3. Or I could use the 4 or 7 buffer solution.

@ajdelange gave me a similar recommendation a couple of years ago when I first bought my Hach meter. I went around the house measuring everything. Orange juice, spaghetti sauce, milk, tap water, beer, you name it. Just rinse with DI water after each measurement and stick the meter back in the 4.01 buffer to make sure it isn't drifting between readings. I'm still not an expert by any stretch, but I'm more comfortable that my readings are good after a couple of years.

 

[dmcmillen]

Are you hoping for 4 or lower DI_mash pH results for your 65L Brown malt that will justify mashing your recipes grist into your water at a measured pH of 5.18 so as to verify the superiority of the empirical method over that of your actual DI_pH testing?

No, not that at all. I think the Brown Malt diph reading is pretty accurate. I just want to play around with the meter and get more comfortable when the reading is stable using AJ's technique.

 

[ajdelange]

Bru'n Water does not use DI pH in its calculations. It uses a malt acidity in combination with the alkalinity of the brewing liquor to arrive at a net acidity that is then correlated to a predicted mash pH.

How does one determine "malt acidity"? IOW if I have a sample of malt on the bench, how do I measure this.

I can't see how a DI pH value can reliably be used in the complexly buffered mash system, thus the reason I never considered DI pH in practice.

You really need to understand this because it is apparent from your comments that you don't appreciate that what you are advocating as an alternative, i.e. modeling malt titratable acidity, is exactly what we are doing here except that we are basing our model on measurement, to the extent possible, rather than some empirical relationship between the malt type or color and the characteristics of the curve.

It is obvious that while best results (and these can be really good) require that we determine the actual titration curve for each malt which requires multiple pH measurements we can get a pretty good estimate of the "curve" from a single measurement by assuming that it is linear and that we know its slope to be 45.7 mEq/kg•pH. That single measurement is, of course, the malt's DI mash pH. Malts' titration curves don't all have slope 45.7 and they aren't linear so one can, of course, do better by taking at least one other measurement to determine what the slope actually is (this is the approach Kai originally took and is, I believe, the basis for Brewer's Friend) and better still enough additional measurements to determine the parameters a, b, and c which reproduce the titration cuve in the form:

mEq/kg = a*(pHz - pHdi) + b*(pHz - pHDI)^2 + c*(pHz - pHDI)^3

pHz is the pH realized when mEq/kg acid has been added to a kg of the malt in question. When using the titration curve to control or predict mash pH pHz represents the target pH. It depends much more strongly on pHDI than on any of the other parameters as you can easily see by calculating the total differential WRT to each:

∆mEq/kg = -∆pHdi*(a + 2*b*(pHz - pHDI) + 3*c*(pHz - pHDI)^2)

+∆a*(pHz - pHdi) + (pHz - pHDI)^2*∆b + (pHz - pHDI)^2

To give a general idea we observe that a is about -45 mEq/kg•pH for most malts (excepting sauermalz) and that most malts are fairly linear so that b and c tend to be small relative to a and that, for base malts pH - pHdi tends to be 0.4 pH or less for most values. For Crisp's Maris Otter the parameters are (a = -46.589, b= 6.3516 , c = -2.623, pHdi = 5.69). The grain related error in pH from mis modeling of the mEq/kg calculation is simply the error in mEq/kg divided by the buffering of the mash which is, for each grain approximately a so we can say that, approximately,

∆pH ≈ -∆pHdi -∆pHdi*(2*(b/a)*(pHz - pHDI) + 3*(c/a)*(pHz - pHDI)^2)

+(∆a/a)*(pHz - pHdi) +(∆b/a)* (pHz - pHDI)^2*) + (∆c/a)*(pHz - pHDI)^3

Putting in the numbers for Crisp MO

∆pH ≈ -∆pHdi + ∆pHdi*(0.078 + 0.014)

-(.29/a)*∆a+ (0.1682/a)*∆b -(0.073/a)*∆c

At this point we would model the errors as random variable and look at the rms error

s_pHrms = sqrt( (1.092*s_pHd)^2 + (s_a*0.0124493)^2 + (s_b*0.168)^2 + (s_c*0.073)^2 )

s_x in this last formula represents the standard error in an estimate.

If we know the titration curve shape perfectly (s_a = s_b = s_c = 0) then the error in our pH approximation will be approximately 1.09 times our error in knowledge of the DI mash pH. This is why it is so important that we know that. If we have perfect DI mash pH knowledge (s_pHDI = 0) but our estimate of the slope is in error (rms) by 14 mEq/kg•ph (the standard deviation of all the malt slope data I have excluding sauermalt's) and we assume the curve is linear (which this malt isn't) then the standard error in the pH would be 0.09 pH. Actual mash pH's would differ from this and the analysis would be based on weighted sums of malt masses but the message should be clear: If we have the malt's DI pH we can get by with a pretty good size error in knowledge of slope. But, of course, if we know the slope we can knock out the slope part of the error budget. And if we know the curvature we can knock those errors out too. Then you have a robust method.

The argument that pH can't relate what is in a wine like a titratable acidity test can, is the reasoning behind going with the malt acidity approach in Bru'n Water.

You seem to be missing the essential point that titratable acidity is a function of pH. The DI mash pH is simply the point on the titration curve at which no acid or base has been added.

Its a strong reason why its model seems to be more robust than others.

It may be more robust than some but it is certainly less robust than a model that takes in pHDI as an input. If you are using an acidity model you must have a titration curve and, as you are not iterating for an answer (AFAIK) your "curve" must be linear. That "curve" requires two parameters to describe it: slope and the value of pH at some level of added base or acid. It doesn't mater what level is chosen/ The obvious one is 0 and the pH at that point is the DI pH. Whether you realize it or not you are effectively doing what I am describing here but as you must deduce pHDI and slope (a) from the malts' descriptions and/or colors you clearly can't get estimates of mash pH that are as good as a program that actually knows the DI pH (unless it makes really bad slope estimates. In the case in point here OP has measured the pHDI of his malt and we can, using that in a robust program, get a much more reasonable estimate of mash pH (about 5.6) than he was getting from Bru'n Water.

You'll never see a vintner considering pH over TA when assessing the quality and character of their products.

And you'll see precious few brewers measuring the titratable acidity of his beer. Well, lambic brewers probably do like to see TA data. But this is kind of a non sequitur as we are talking about mash pH prediction, not QA.

Just to make it abundantly clear
1)You are using malt acidity
2)Kai is using malt acidity
3)Silver is using malty acidity
4)A.J. is using malt acidity.

The latter two are just doing it more robustly by using measurement data when they can get it.

 

[ajdelange]

Out of the box, 'Mash Made Easy' predicts 5.00 as the pH for a 65L "Brown" malt.

If I take all the °L vs pHDI data I have (which is mostly Kai's) and do a linear fit r^2 = 84% (which some interpret as good). The resulting model predicts the DI mash pH for 65L malt to be 4.78. MME predicts 5 and OP measured 5.14. I don't think I've ever seen an example which illustrates the value of using actual DI mash pH quite so well.

 

[cire]

Tested in the last hour.........
31g MO 5 EBC
18g brown malt 130 EBC.
150ml liquor 98ppm alk as CaCO3 with 100ppm Ca.
After 15 minutes @ 150 F, pH was 5.10.

 

[ajdelange]

So clearly your Brown malt is lots more acidic than OP's. What's its DI mash pH?