pH Problem?

[dmcmillen]

I just did my first brew of a Munich Helles (5.5 gal) checking pH with a new Milwaukee MW102 pH meter. I calibrated the meter per instructions the day before brewing with no problems. Mash & Sparge water treatment per Bru'n Water predicted 5.4 mash. At 12 min pH=5.44, 30 min 5.58, 40 min 5.55, 60 min 5.6. At the 60 minute mark I added .2 ml Lactic Acid (my .1 mash pre-calculated adjustment), re-circulated and stirred the mash and re-measured and now measured >6. For measurements I strained out any grain pieces.

The Helles has now been in primary for a week and measures 4.25 which I think is a little low. My understanding is that Ale should be 4.0 - 4.5 and Lager 4.4 - 4.7.

No other problems on brew day other that gravity being a little high due to more than anticipated boil off for 90 min boil.

Could this have anything to do with the fact that I have .69 gal underlet volume under the false bottom which tends to dilute the mash volume. For this brew my calculated mash water was 3.41 gals for the grain (1.3) + .69 underlet volume = 4.10 gals (amt fed to Bru'n Water). I typically only recirc that water thru the grain if I am applying heat. Prior to this I was brewing 11 gal batches for which the underlet volume is a very small percentage compared to a 5 gal batch.

Since this is my first time checking pH I would appreciate some thoughts here. Is this a possible problem? Normal?

 

[didinho]

Since this is my first time checking pH I would appreciate some thoughts here. Is this a possible problem? Normal?

ph is important for efficiency, and (in black beers) to avoid tannin extraction.

if your ph is correct at the beginning of mash and the conversion was ok, no need to worry if it changes during the mash.

 

[ajdelange]

I just did my first brew of a Munich Helles (5.5 gal) checking pH with a new Milwaukee MW102 pH meter. I calibrated the meter per instructions the day before brewing with no problems. Mash & Sparge water treatment per Bru'n Water predicted 5.4 mash. At 12 min pH=5.44, 30 min 5.58, 40 min 5.55, 60 min 5.6

It is normal for pH to drift upwards over the course of a mash but not usually as much as 1.6.

At the 60 minute mark I added .2 ml Lactic Acid (my .1 mash pre-calculated adjustment), re-circulated and stirred the mash and re-measured and now measured >6.

It is definitely not normal for mash pH to increase after an acid addition.

I suspect the pH meter (I always do when people get reading that don't seem right). The MW102 is on the list of meters that has passed muster here but that doesn't mean uyou couldn't have gotten a bad one from the factory.

Since this is my first time checking pH

Actually, that is a likely explanation. Proper use of a pH meter takes a little practice. Read the Sticky at https://www.homebrewtalk.com/showthread.php?t=302256. Get some data for the stability check. This will get you both some experience with using the meter and the assurance that there is nothing wrong with it. If you can't pass the stability check keep trying until you can. If you can't after a couple of tries, then you have a bad electrode (most probably) or meter.

The Helles has now been in primary for a week and measures 4.25 which I think is a little low. My understanding is that Ale should be 4.0 - 4.5 and Lager 4.4 - 4.7.

Yes it is but not disastrously low. This is with a freshly calibrated meter?

 

[dmcmillen]

Thanks AJ. If nothing wrong with the meter, my suspicion is user error. I'd pick me right now over the meter. I'll reread your post again and play around with the meter some more to get more comfortable with using it. I did play around with it the day I calibrated it. Seems pretty easy to use. Have to make sure you let the reading stabilize and not contaminate the probe when taking a reading.

 

[ajdelange]

Well don't take this personally but I am betting it is you too. I learned years ago that every time I got in a new piece of test equipment that the first assays I ran with it were all over the map. After running a few more the answers began to make more sense though I could not usually point to something I was doing wrong. A lot of the stuff at the linked post is there in the hopes that it will alert people to some common pitfalls. You are already aware of the big ones: contaminated buffers, old buffers, failure to wait for calibration readings to stabilize, failure to wait for sample reading to stabilize.

 

[dmcmillen]

AJ, I finally got to work with my MW102 pH meter yesterday. I calibrated and performed the stability tests that you suggested in your doc. All tests were performed with the 4 solution. Based on the results I don't think anything is wrong with the meter which is pretty much what I expected.

Manual says the reading is ready when the hour glass goes off, but the reading always continues to drop if I let the sample stand for another 20 - 30 seconds, so I am providing both readings, the 1st when the hour glass goes off and the 2nd when the meter "stabilizes"

Results Every 2 minutes for 20 minutes (All readings at 73F)
4.06 4.01
4.03 4.00
4.01 4.00
4.02 4.00
4.01 4.00
4.01 4.00
4.01 4.00
4.03 4.00
4.02 4.00
4.01 4.00

Results Every 10 mins for 2 Hours - New Solution Sample (All readings at 73F)
4.07 4.03
4.05 4.01
4.07 4.01
4.03 4.00
4.05 4.00
4.05 4.00
4.02 4.00
4.02 3.99
4.04 3.99
4.04 3.99
4.03 3.98
4.03 3.98

 

[ajdelange]

Well glad to hear the meter is OK. That leaves us with trying to explain how you mash pH went up over 6 from 5.55 just after adding acid. This does not happen so even though the obvious cause - faulty electrode - has been eliminated I'm afraid I can't come up with any better explanation than "Faulty reading with good electrode." This does happen - happened to me Sat. Turned out the electrode's junction needed to be renewed. Did that and everything was fine. Now I have enough experience to be able to look at a pH reading and say "That doesn't look right - let's check the junction." but you clearly don't as you just bought the meter - I guess in fact you do have one piece of experience i.e. this one. Whenever a reading doesn't make sense (having the pH go up as much as 0.16 should put you on alert; having it go up after adding acid does not make sense) immediately check the calibration with the 4 buffer. You said in the OP that you removed mash particles from the sample. You usually don't have to do that but my best guess at this point would be that a particle of husk or something blocked the junction. I say that because 99% of pH measurement problems seem to turn out to be related to the reference junction somehow or other.

 

[dmcmillen]

Given my inexperience with the meter and that I only have my first calibration and one set of data on that brew day (other than the recent calibration & stability tests) under my belt, I'll make sure to exercise extreme due diligence on my next brew day which should be sometime this week. Who knows, maybe I didn't stir and recirc enough after the acid addition. After all the pH was 4.25 after a week in primary. It can get a little hectic on brew day at times.

By renewing the electrode junction do you mean disconnecting and reconnecting it to insure good connection?

 

[ajdelange]

By renewing the electrode junction do you mean disconnecting and reconnecting it to insure good connection?

In your electrode there is chamber filled with potassium chloride solution which is also saturated with silver chloride. In the 'bulkhead' through which the bulb stem and RTD protrude there is a piece of fritted material (but in some modern designs) just a piece or rag that connects the KCl chamber to the outside of the electrode. KCl solution passes through this frit (or rage) forming an electrical circuit between the sample and the reference electrode located in the KCl chamber.

There is really no maintenance except blasting the junction area with a stream of DI water if something settles over it.

In the electrode I was referring to the reference is a 1 mm (or so) plastic tube which sticks through the bulkhead. At the other end of the tube is a cartridge of glycerin saturated with KCl and AgCl, connected to a pump operated by a button. To make the electrical contact the pump is operated until a glob of glycerin appears at the end of the tube near the bulb. The junction is the interface between that blob and the sample. My cartridge ran out, the glycerin got washed away from the end of the tube and the junction was, therefore, up inside it where it did not have good connection to the sample. A new cartridge and a few strokes on the pump solved the problem.

It's really a great design because you cannot foul your junction. If it gets plugged you just put a syringe with a Luer tip filled with DI water on the cartridge end and blow whatever is blocking things out of the way.

 

[dmcmillen]

AJ, I finally brewed a robust porter yesterday with 11.8 lbs pale ale, 1.06 lb crystal 90, 1.06 lb chocolate. Final water profile was Ca 59.8, Mg 5.3, Na 28, SO4 52.4, Cl 61.4, HCO3 119.7. Bru'n water estimated mash pH 5.5. Everything looks ok in Bru'n Water. Grain bill with lovibond ratings entered correctly.

Results of the mash are (minutes, pH, temp):

5----5.28---30.1
17---5.20---30.2
27---5.20---30.3
37---5.19---29.8
49---5.18---30.8
60---5.19---29.0
Added .5g Baking Soda (my pre-calculated addition to raise pH .1
65---5.21---28.0

Preboil after fly sparge 5.1 @ 24.1

This is about .3 below Bru'n estimate. I would think that's a pretty large difference. Meter was calibrated and I was very rigorous in measuring procedures, rinsing the electrode and temp probe with DI and dabbing dry with paper towel, etc., etc. Mash was recirculated and stirred before taking sample.

At this point I'm just at a loss as to what's going on. Is there something wrong with the grain? Does my .69 gal below the false bottom have anything to do with this? After adding the .5g baking soda I didn't get the .1 rise in pH expected.

 

[ajdelange]

At this point I am as mystfied as you. Things are ostensibly happening that just can't happen. I would suggest brewing a beer without fiddling with the water i.e. just use DI water with half a ts of calcium chloride for each 5 gal. Things will straighten out a you get more experience with the meter.

 

[mabrungard]

You mention the space under the false bottom. How are you mixing the mash, or are you recirculating to mix? How was that baking soda addition added? Did you check the wort pH in the kettle prior to boiling?

Your result is a bit odd since Bru'n Water typically predicts slightly on the low side. I can only assume that the base malt you are using, has a lower than expected distilled water pH result.

 

[dmcmillen]

Martin, my system is a single tier, 2 pump system of 3 15.5 gal keggles. The mash tun has .69 gal below the false bottom which my mash volume includes. For this brew (robust porter) I treated my water to a final water profile of Ca 59.8, Mg 5.3, Na 28, SO4 52.4, Cl 61.4, HCO3 119.7 (no DI required). I fill my mash tun with the mash water, make my water additions, and recirculate wide open for several minutes while stirring like hell to insure mixing. I then heat the mash tun to strike temp while recirculating, turn the pump off and stir in the grain and stabilize the temp to mash temp. From that point forward I only recirc (slowly) if I have to apply heat or am taking a sample. While taking a sample I recirc and stir like hell.

For this brew, Bru'n Water estimated 5.5 for the total volume of mash including the .69 gals. I can't help but think this has something to do with the .69 gals since most of the mash is without it although it does get mixed in when applying heat and taking samples.

Preboil pH was 5.1. Base malt is a Rahr pale ale which runs from 1.8 to 2 lovibond.

By playing with the beginning Bru'n Water additions that I started with, I kept adding small increments of Baking Soda until I hit the amount that would raise the pH by .1. That was .5g, which I added to the mash while recircing and stirring. I mostly did this addition to see the effect. I was so far off that I wouldn't want to add that much to get the pH up that much.

I believe my testing procedure is ok and I've determined the meter is accurate and not drifting. At this point I really don't know what to do other than design a brew where I have "better" control over the parameters which I believe AJ is suggesting.

My gut feeling is that this has something to do with the .69 gals below the false bottom or I'm just doing something stupid. Anyway I appreciate all the help. I really wanted to elevate my brewing to the next level with water and pH treatment. Didn't expect this big a challenge.

 

[mabrungard]

No, the deadspace volume under the false bottom should not alter your result. As you point out, that volume does eventually become part of the wort upon any recirculation.

You did identify a likely culprit. The Rahr 2 row is reputed to have a lower than typical distilled water pH. I've found that you can generally account for the increased acidity of that base malt by arbitrarily increasing the color rating of that malt by about 3 to 4 lovibond...so changing the color setting of that grain to about 5L in this case. Why don't you make that change in the program and see what the pH prediction is then. I'm sure that it will be much closer to your observation.

This characteristic of Rahr base malt is discussed in the Bru'n Water comments, but you may not have seen that. I apologize for your discrepancy.

 

[dmcmillen]

Thanks Martin. Probably read that at one time. I have to change the color from 2 to 12 to bring the pH from 5.5 to 5.2. (4=5.4, 8=5.3). I am trying to understand what I should do in the future to determine any necessary additions to adjust pH if I use Rahr base malt. Is the 5L suggested based on some experience? The 12L is higher so I'm not sure whether I should use 12L going forward.

If I were to brew this robust porter again, I would set the Rahr base malt to 12L (based on the the pH measured for this brew), and get an estimated pH of 5.2. Then I would make additions to increase the alkalinity to a pH of 5.4 which would be baking soda or chalk (not easy to add). I will measure the pH of this brew when I move to secondary some time this week.

Anyway, trying to determine what I should do moving forward. What is the purpose of Rahr acidifying the grain. I know we can use an acidulated malt to lower the pH instead of an acid addition but I believe that's all the malt does.

 

[mabrungard]

Given that you had to change the color rating of the base malt by that much, it is unlikely that it was only the malt acidity that varied. You didn't describe your water source, but does it have alkalinity? If so, it appears that the current alkalinity of your water source is lower than you expected. It may be worth measuring its alkalinity to verify that it matches your input assumption.

 

[dmcmillen]

My water source based on a very recent Ward Labs analysis is pH 7.5, Na 28, K 4, Ca 9, Mg 4, Total Hardness CaCO3 39, SO4 3, Cl 4, CO3 <1, HCO3 119, Total Alkalinity CaCO3 98, very soft water. For this robust porter I made adjustments to reach the Brown Malty profile. Based on the additions the final profile was Ca 59.8, Mg 5.3, Na 28, SO4 52.4, Cl 61.4, HCO3 119.7. For 5.25 gals mash, the additions were 1.6g CaSO4, .3g MgSO4, and 2.4g CaCl. I used a jeweler's scale to measure the additions. They were added to the mash water as I heated to strike temp while recircing wide open. I used 11 lbs 13 oz of the Rahr Pale ale at 2L, 1 lb 1 oz of Crystal 90 at 90L, and 1 lb 1 oz of Chocolate at 350L.

If you want I can sent you a copy of the Bru'n Water xls for this recipe. Good idea on the alkalinity. I will measure a sample of the water tomorrow and post results.

 

[ajdelange]

You did identify a likely culprit. The Rahr 2 row is reputed to have a lower than typical distilled water pH.

That rumor about Rahr went around a couple years back. A guy I correspond with measured Rahr Pils using a modification (simplification) of my published method and came back with a DI mash pH of 5.8 and first order buffering coefficient of -46 mEq/kg•pH so I don't think that is what's responsible here.

I can't say what is responsible but I am guessing that additional experience with pH measurement will cause it to go away.

 

[dmcmillen]

Sounds like the Rahr is not a problem. I just tested the pH of my brewing water. See below. I have a whole house filtration system which removes all the bad things and chlorine other than the minerals. The house has also been completely replumbed with pex so nothing coming thru from old pipes. The tankless water heater was installed about 7 years ago. A sample of that filtered water coming out of the cold sink in the basement where I brew is what I sent to Ward Labs for testing. The results are listed below in a recent post. The Ward Labs pH was 7.5.

Probe is stored in storage solution. I first calibrated the MW102 meter. No problems there. I have an area set aside for testing and am testing according to AJ's procedures. Pretty straight forward. Rinse the electrode & temp probe with DI (purchased at Walmart), shake, dab off with paper towel, immerse in test sample, shake lightly in sample, and take the reading. Meter says stable with hour glass goes off, but I continue to observe until stable. I use a squirt bottle of DI for rinsing. I make sure not to contaminate the solution. I rinse with DI before storing in DI before next test.

Today the testing of my water the reading (except once) continued to change until the meter turned off.

- First reading is when hour glass turns off (when meter says reading is ready).
- 2nd reading is when meter turns itself off (10mins or so)
- All lines were flushed prior to taking sample
- All water samples come thru the filtration system
- Hot samples come thru the tankless heater
- fyi, I fill my keggles with Hose Hot (potable hose)

1. Calibrate meter
2. Sink Cold Sample------6.12----6.85----23.3C
3. Hose Cold Sample-----6.99----7.09----23.4C
4. Sink Hot Sample-------7.17----7.14----26C (stabilized within 2 mins)
5. Hose Hot Sample------7.27----7.47----26.1C

I am very comfortable with taking samples and readings. I am seeing variation here where I would expect more consistency.

Any suggestions?

 

[mabrungard]

The pH of your water is meaningless in brewing. The ionic content and especially the alkalinity are the most important facets of your water. However, your readings do show significant variation. If your water is only lightly mineralized, it is possible that the low ionic strength of the water is making it difficult for the meter to measure pH.

 

[dmcmillen]

Water is lightly mineralized. Ward Labs analysis is pH 7.5, Na 28, K 4, Ca 9, Mg 4, Total Hardness CaCO3 39, SO4 3, Cl 4, CO3 <1, HCO3 119, Total Alkalinity CaCO3 98, very soft water. I treated my water to a final water profile of Ca 59.8, Mg 5.3, Na 28, SO4 52.4, Cl 61.4, HCO3 119.7 (no DI required). I was measuring pH to get more experience with the meter and to check consistency and to compare to the Ward Labs measurement of 7.5.

It may be worth measuring its alkalinity to verify that it matches your input assumption.

Input assumption is the 98 CaCO3 from the Ward Labs test. Note that in 2012 my unfiltered water alkalinity was 70 CaCO3. Would have to do another lab test to verify. My guess is that another test would be close. I'm not sure it can get low enough to explain the difference in mash pH (5.2 vs est 5.5)

 

[dmcmillen]

Porter has been in secondary on the vanilla beans for a week now. pH is 4.12. A little low but still within range. It is slightly tart for my taste. Not sure if the vanilla effects the pH.

 

[mabrungard]

It does appear more likely that your water's alkalinity was not where you assumed it was. 4.12 for an ale isn't way out of line, but it is probably lower than desirable for that beer.

 

[trentm]

Hey dmcmillen, I've used the Milwaukee 102 for a couple of years now. One thing I've learned is to move the probe around in the solution you are measuring until you get a stable reading.

 

[ajdelange]

If you are using your electrode properly the last thing you did to it before dunking it in the sample was rinse it with DI water. When you put it in the sample moving it about a bit rinses that DI water off the sense bulb and the reference junction. You don't need to keep it in motion, however. To do so produces 'stirring error'.

 

[dmcmillen]

Martin. The Ward water analysis was 2/15/2016, pretty recent, and the alkalinity was pretty close to what it was about 4 years ago, so I'm doubting that the "problem" is the water alkalinity. However, to eliminate the water, I will brew my next batch with 100% DI and build the water chemistry up from there.

AJ, I know you believe that the problem I'm experiencing with the measurement not matching the Bru'n Water prediction is my inexperience with working with the meter. However, I have spent quite a bit of time using the meter and I have the process (actually your recommended process) down. It's not rocket science. You just have to be careful not to contaminate the sample and do due diligence in taking the measurement. I have a work area set up that I use where I cool down my samples and take my measurements. I stir and recirculate my wort to make sure it is thoroughly mixed before taking the sample. Then I take the sample from the top of the mash and strain it into a small beer sample glass (I use this glass because it is small and the probe and electrode sit in the sample without tipping the glass over). I then cool the sample down. I turn the meter on, rinse the electrode and probe with a squirt bottle of DI, shake them, and dab them off with a new paper towel. I insert the electrode and probe into the sample, stirring them for a moment, and then take the reading. The MW102 manual says the reading is ready with the hour glass goes off, but I usually wait a couple of minutes for the reading to stabilize. When I have taken the sample I rinse the electrode and probe off with DI and store in DI. I have been recalibrating the meter on brew day.

I am trying to think out of the box here but I'm mystified. I know I am measuring my additions correctly. I see lots of posts by people that use Bru'n Water and are never more that .01 - .02 off. This brew was .2 off. That's huge.

 

[ajdelange]

However, to eliminate the water, I will brew my next batch with 100% DI and build the water chemistry up from there.

When you have a complex system (such as a mash) and a behaviour you cannot explain you need to eliminate one variable at a time until you find the culprit. Brewing the next one with DI and a little calcium chloride/sulfate is a good move in this regard.

AJ, I know you believe that the problem I'm experiencing with the measurement not matching the Bru'n Water prediction is my inexperience with working with the meter. However, I have spent quite a bit of time using the meter and I have the process (actually your recommended process) down. It's not rocket science.

No it isn't but it is also a fair amount art. You cannot expect to take up a new tool and be adept in its use the day you take it out of the box. The 'stirring error' which came up yesterday is perhaps a good example of this. It is something I deal with without even thinking about it enough to have mentioned it in the sticky. It's part of the art of pH measurement.

You just have to be careful not to contaminate the sample and do due diligence in taking the measurement. I have a work area set up that I use where I cool down my samples and take my measurements. I stir and recirculate my wort to make sure it is thoroughly...been recalibrating the meter on brew day.

You are for sure doing the right things and will soon be adept (will have acquired the art as well as the science). You have by now acquired some of it so that were I to be coming in here I might not put head-set error at the top of the list. Earlier you were posting that you added acid and the pH went up. That doesn't happen and I expect at this point you would be aware of that and start investigating why you saw that.

I am trying to think out of the box here but I'm mystified. I know I am measuring my additions correctly. I see lots of posts by people that use Bru'n Water and are never more that .01 - .02 off. This brew was .2 off. That's huge.

Actually it isn't. A program that uses color as a basis for determining the DI mash pH and first order buffering for the proton balance equation is going to be off that much fairly frequently. There is another current thread where this is being discussed relative to Golden Promise which behaves, by the Bru'n water model, more like a 10L malt than a malt of whatever color it actually is. One of the malts you are using may be an equally poor fit to the program's model. The workaround proposed in that other thread was to change the color of the malt entered into the program until the measured pH was matched. That's fine if you are absolutely sure that the pH measurements are correct.

To put this in further perspective: The best theoretical accuracy for a good pH meter using NIST ± 0.02 buffers is about ± 0.014 pH. Does it strike you as strange that lots of people consistently get pH readings within 0.01 - 0.02 pH of Bru'n Water's predictions? It should!

 

[dmcmillen]

Well, I would certainly like to get to the point where I am can practice the artistic side and design and brew beers where I can control the water chemistry/pH to get the flavor/taste/mouth-feel/etc. that I want. Right now there is such a large gap between design and end result that I can't make up for it with additions. That's what I meant when I said the .2 difference was huge. Actually it was .3. If it's not uncommon to have differences that large, how are people making adjustments to get where they want? I obviously don't know the science here (except at a rudimentary level), but it would be helpful to understand how much variability I should expect throughout the process.

A lot of variables involved, especially the fact the the pH estimate is based on color of the grain. Could be a problem with the program (unlikely since Kai's program estimated 5.4), my water, the grain (what if I used the wrong grain or the grain used is acidified more than we believe), the meter (eliminated), measurement techniques (eliminated), and others that I may not know about.

Anyway, I appreciate everyone's help with this.

 

[ajdelange]

Well, I would certainly like to get to the point where I am can practice the artistic side and design and brew beers where I can control the water chemistry/pH to get the flavor/taste/mouth-feel/etc. that I want.

Every time you brew you are taking a step in that direction.

Right now there is such a large gap between design and end result that I can't make up for it with additions. That's what I meant when I said the .2 difference was huge. Actually it was .3. If it's not uncommon to have differences that large, how are people making adjustments to get where they want?

This is why I do not advocate blind reliance on calculators or spreadsheets. Even the most robust (and most aren't that robust) can surprise you occasionally and there is no way to predict when those occasions might be coming beyond the obvious observation that a brand new exotic malt you have never measured potentially may not fit your model.

I obviously don't know the science here (except at a rudimentary level), but it would be helpful to understand how much variability I should expect throughout the process.

I'd say ± 0.2 when just starting out. Many get better than that after gaining experience with particular beers that they brew often. An example of this has come up recently with the discovery that Bru'n water gives better mash pH prediction if you tell it that Golden Promise is 10L than if you tell it it is 3L.

A lot of variables involved, especially the fact the the pH estimate is based on color of the grain.

I think this is the biggest problem. The correlation between log color and DI mash pH is only 0.92. That sounds pretty good but it isn't really.

Could be a problem with the program (unlikely since Kai's program estimated 5.4),

All of the programs that I am aware of assume the buffering of malt is linear with pH. It isn't. This does not make a difference when the DI mash pH is close to the target mash pH because the curves are nearly linear in a small region. Malts that have DI mash pH's appreciably different from target pH tend to be used in small quantity.

my water,

Mains or well water can be quite variable seasonally. If the alkalinity changes the estimated mash pH will change too.

the grain (what if I used the wrong grain or the grain used is acidified more than we believe),

A sack of winter crop malt from Crisp isn't the same as a sack of summer crop malt from crisp nor is it the same as one of either from Munton's or Fawcett. This is the real problem as I see it. I'd like maltsters to make the basic measurements and put the results on the sacks in a form the brewer can easily utilize. That is doable but nobody seems to want to do it.

the meter (eliminated), measurement techniques (eliminated),

We are going to assume that eventually, if not already, you have got the pH measurement thing under control. Herein lies your salvation. After your spreadsheet shows that you will realize a mash pH of 5.48 with a particular grist you don't go and brew it and then knash your teeth when you observe a mash pH of 5.78. What you do is mash about a pound of the grist and measure its pH the day before you brew. If it's pH is 5.78 you have a day to figure out why and what to do about it.

 

[dmcmillen]

AJ, I hope you're still monitoring this thread. I am finally ready to brew an American Amber Ale (10B), OG 60, SRM 13, IBU 5. My grain bill will be 10lb 3oz Breiss 2-row (I will use the Briess this time instead of the Rahr Pale Ale), 1lb 15oz Crystal 10L, 3oz Chocolate (350), and 6oz Carapils. It will be a chili beer with peppers added in boil and secondary. So I need to figure out what I need to do with the water/pH. From the previous posts, I have been from .2 to .3 off the Bru'n Water predicted pH for the last 2 brews.

My water profile is pH 7.5, Na 28, K 4, Ca 9, Mg 4, Total Hardness CaCO3 39, SO4 3, Cl 4, CO3 <1, HCO3 119, Total Alkalinity CaCO3 98. Looks like a Bru'n Water profile of either Amber Malty or Amber Balanced would be appropriate. You had suggested to perhaps use all distilled water with just a little calcium chloride/sulfate added for my next brew to help pinpoint the reason for the discrepancy between measured pH and predicted.

I would appreciate some suggestions here. Thanks, David.

 

[ajdelange]

As suggested earlier the best thing to do is remove as many variables as possible. A potential major one here is temporal variation in the water's alkalinity. This can easily be removed by removing all the alkalinity which is simply done by titrating the water itself to mash pH. A much simpler approach is to realize 0 alkalinity water by using RO water. Add calcium salts in equal amounts to the extent of perhaps 2 mEq/L each of sulfate (96 mg/L) and chloride (70 mg/L). This will give you 3 mEq/L (60 mg/L) calcium total which is plenty. You will adjust the sulfate and chloride levels upon tasting the finished beer adding more or less of each dependent on whether added sulfate/chloride improves it or degrades its flavor.

To hit pH 5.4 with the proposed grist you will need about 3% sauermalz (6 Oz) but this is an estimate based on malts similar to the ones you are using as I don't have data on the actual ones you are using. With the popular brewing spreadsheets you get errors from modeling the malts by their colors which is clearly inadequate but gets you a ballpark number in most cases. In my calculations you get errors from modeling your malts as ones that I or others have measured which is clearly inadequate but gets you a ballpark number in most cases. This is why it is so important to do a test mash.

 

[dmcmillen]

How about distilled water? I don't have a source for RO water where I live. I believe ro water has a ph of 5 - 6 and distilled water 7.0 so how much acid would you suggest. Also, I currently do not have any acidification malt, so I would have to use lactic acid. What's the ratio of acidification malt to lactic acid?

If I read you correctly, you are suggesting to mash with NO minerals, only acid to see if pH hits close to expected 5.4 and then make additions prior to kegging and carbonating. I suppose I can do this but this is a pepper beer with Jalapenos and Anaheim peppers in the boil and secondary so that may be difficult.

 

[ajdelange]

How about distilled water?

Distilled is fine. It has very low mineral content and that is what we seek. We want all (or at least the vast majority) of the minerals in the water you brew with to be under your control.

I believe ro water has a ph of 5 - 6 and distilled water 7.0 so how much acid would you suggest.

As both are low in minerals (very low alkalinity) both are influenced by the small amount of CO2 in the air and will have pH's in the 5's and 6's.

Also, I currently do not have any acidification malt, so I would have to use lactic acid. What's the ratio of acidification malt to lactic acid?

Acidulated malt is malt as well as containing the acid needed to neutralize base malt alkalinity. There is, therefore, no 1 - 1 equivalence. The sauermalz recommendation I gave was based on an estimate of 57 mEq acid needed for base malt neutralization. As the 88%lactic acid sold by most homebrew shops is 11.4N you would need about 57/11.4 mL. But if your actual base malt is more or less alkaline that the one I used for my calculation (Rahr) then you will need more or less acid so it is important to do a test mash.

If I read you correctly, you are suggesting to mash with NO minerals, only acid to see if pH hits close to expected 5.4

No. I said that if you wanted to stick with your water with its possibly varying alkalinity that you can deal with that variable alkalinity by adding acid until pH 5.4 (or whatever mash pH you fancy) is reached. As this can result in potentially widely varying acid cations in your beers I suggested that starting with 0 mineral (or very low mineral) water is a better way to do things and that if you start with 0 mineral water you should add salts in sufficient quantity to result in about 2 mEq/L each of chloride and sulfate.

... and then make additions prior to kegging and carbonating.

Misunderstanding here too. Two mEq/L each SO4-- and Cl- may give you a beer you like (and very probably will) but there is a good chance you can tune the amounts of these ions to get one you like better. To help you to determine whether to add more or less sulfate and chloride I recommended tastintg the beer made with 2 mEq/L of each and then tasting again with small supplements of sulfate and chloride salts. An improvement in flavor when adding an ion suggests that a subsequent brew might benefit from a bit more of it. A degradation in flavor suggests that it might be beneficial to brew with less of that ion next time.

 

[dmcmillen]

Thanks AJ. Got the misread. Were you estimating based on Rahr Pale Ale because that is the base malt I usually use and would prefer to use.

Can you suggest the parameters for a test mash please. Just the base malt, or all the grains and how much to scale down.

I recommended tastintg the beer made with 2 mEq/L of each and then tasting again with small supplements of sulfate and chloride salts.

What quantity of the beer would you suggest to use? A glass or 12oz would require extremely small additions. Also, pre or post carbonated beer?

Lastly, I'm sure you can tell I'm not a chemist. I am college educated in the sciences. Many people like to use mEq/L which I understand to be milli-equivalent/L or one thousandth of an equivalent weight and the equivalent weight of a substance is the amount of a substance that displaces so much oxygen or hydrogen. First of all, I don't know what that is for say SO4 or Cl nor do I know how to convert to a more useful measurement like mg/L or even ppm. I'm sure you've been trained in and have been doing this for a long time so that you can probably make the conversion in your head, but a layman like myself could use a little help or direction here.

 

[ajdelange]

Were you estimating based on Rahr Pale Ale because that is the base malt I usually use and would prefer to use.

I used Rahr because you said that you used it and I have some data on it. The fact that it isn't the same batch or season as the actual you are using says that there will be an error in the estimate but the fact that it at least comes from the same maltster under the same label says that the error will be smaller than if I used some other pale malt's data.

Can you suggest the parameters for a test mash please. Just the base malt, or all the grains and how much to scale down.

As the goal is to estimate the pH of the actual mash you will achieve the test mash composition should be as exactly the same as that of the full mash but the total amount of grain mashed should be small i.e. a pound or less. Use water treated the same way as the water you will brew with and in the same proportion. Heat it to the strike temperature you plan for and try to hold the mash at something close to the temperature you will hold after strike for 10 or 15 minutes. Then withdraw some of the liquid, cool it to room temperature and measure the pH.

What quantity of the beer would you suggest to use? A glass or 12oz would require extremely small additions.

Most guys seem to make solutions of gypsum and calcium chloride and add drops of them to a glass of beer.

Also, pre or post carbonated beer?

It should be as close to the finished product as you can get it. Clearly stirring in drops of salt solutions is going to disturb the carbonation some so stir gently.

Lastly, I'm sure you can tell I'm not a chemist. I am college educated in the sciences. Many people like to use mEq/L which I understand to be milli-equivalent/L or one thousandth of an equivalent weight and the equivalent weight of a substance is the amount of a substance that displaces so much oxygen or hydrogen.

The concept of equivalence is base on how much of something reacts with something else. Because it is necessary to specify precisely what is reacting with what IUPAC is apparently moving away from this but for this restricted application it is just makes things so simple that I can't resist using it. Here a mEq is simply a mmol of electric charge. If one must add 2 mmol of an acid to neutralize a base malt's alkalinity and each molecule of that acid contributes 2 protons to the process we say we have added 4 mEq of protons as each proton has unit charge. The malt has 4 mEq of excess negative charge at its natural pH relative negative charge at the desired pH. We say it has a 'proton deficit' of 4 mEq. When supplied by the acid, these 4 mEq bring the base malt to the desired pH.

First of all, I don't know what that is for say SO4 or Cl nor do I know how to convert to a more useful measurement like mg/L or even ppm.

Simply take the molecular weight of the substance (e.g CaSO4.2H0 where it is 172) and divide by the charge on the ion in question to get the equivalent weight. CaSO4.2H20 yields 2 mEq of charge for each mmol so its equivalent weight is 172/2 = 86. Each mmol of CaSO4.2H2O yiels 2 mEq of Ca++, 2 mEq of SO4-- and 2 mmol H2O (water isn't charged). So 2 mEq of Ca++ comes from 1 mmol of CaSO4.H2O which weighs 172 mg.

 

[dmcmillen]

but the total amount of grain mashed should be small i.e. a pound or less.

Do you think the .69 gals of underlet volume on my mash tun will be a problem with the test mash?

 

[ajdelange]

If you include it in your calculation of grist to water ratio, use that ratio in the test mash and then make sure that the underlet water is thoroughly mixed in during the actual brewing then the composition of the test and actual mashes should be the same.

 

[dmcmillen]

Been out of town and just getting back to this brew. I'm trying to figure out how to do a small test mash with my equipment. My mash tun is a keggle which takes at least several lbs of grain to even get to the temp probe. A 1 pound (or so) mash would just be some grain scattered over the false bottom. I've got a 9 gallon kettle that I'll have to see if my false bottom with fit in. But even that would be the same diameter as the keggle. Otherwise would appreciate any suggestions.

 

[ajdelange]

Been out of town and just getting back to this brew. I'm trying to figure out how to do a small test mash with my equipment.

You don't do it with your equipment. You do it with smaller containers. A stainless steel beaker in a water bath is ideal but a metal pitcher, saucepan or tin in a larger pot of warm water on the stove top is probably what most brewers use.

 

[dmcmillen]

Thanks AJ. That's the conclusion I came to. Am looking for SS containers that I can use. Just hadn't thought through.