Brewing with Low Alkalinity Water

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mabrungard

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RO, distilled, and rain water are examples of low alkalinity water. Brewing with low alkalinity water is almost always a desirable thing. But, there are some mash grists that demand a little more alkalinity to keep the mash pH from dropping too low. Increasing percentages of roasted and crystal malt and grain make it more likely that alkalinity will be needed to moderate those more acidic grains.

An option for reducing the impact of those acidic grains in the mash is to steep them separately or add them at the latter part of the mash. These are workable alternatives.

Adding alkalinity to mash water can be problematic. Chalk is an unreliable alkalinity provider since you have to properly dissolve it with an acid to achieve its full alkalinity potential. Baking soda use is limited by the fact that you're adding sodium to your water and there are definite flavor impacts when added in excess. Pickling lime is a good alternative in that it adds calcium and dissolves fully, but it is a strong caustic and demands careful measurement and dosing.

It has come to my attention that there may be another option for reducing the need for alkalinity in mashing. We know that adding calcium and magnesium to the mash decreases the Relative Alkalinity (RA) of the mash water. We also know that we want a minimum concentration of calcium in our wort to promote yeast health and beer clarification.

My suggestion is that in the case of mashing with low alkalinity water, reserve any calcium or magnesium salt addition from the mash and add that directly to the kettle. In this way, the alkalinity deficiency of the mash water is not made worse by adding those salts to the mash.

This is especially true when working with a highly mineralized water profiles like Burton, Dortmond, or a Pale Ale water. For those waters, the desired sulfate or chloride concentration is often added with calcium or magnesium cations. These water profiles end up needing more alkalinity due to the elevated Ca and/or Mg and the resulting reduction in RA.

So when a program like Bru'n Water indicates that more alkalinity is probably going to be needed, try a recalculation of the mash pH by taking out the calcium and magnesium salt additions. If the mash pH prediction increases into a more desirable range, just reserve those original Ca and Mg mineral additions from the mash and put them directly into the kettle when you boil.

Enjoy!
 
A thought provoking post. Here are a couple of the thoughts (not, for the most part new).

It is quite possible to dissolve chalk in water by following mother nature's way and thus achieve the full alkalinity potential of the salt. The simplest method is to suspend the desired amount of calcium carbonate in the water, use a pump or stirrer to keep it in suspension and bubble CO2 through it until the water turns clear and the pH reaches a reasonable value (less than 8.3). This method takes a long time (a day or more) and, thus, uses a lot of CO2. Calculation of the amount of calcium hardness and alkalinity is trivial if you do this and keep the pH close to 8.3. It's 1 mg/L calcium hardness and 1 mg/L alkalinity for each mg/L of chalk added.

The process can be accelerated if the partial pressure of CO2 is increased as by putting water and chalk in a Cornelius keg under a couple of atmospheres CO2 pressure and shaking. The chalk will dissolve much faster. The calcium bicarbonate solution thus prepared is added to the water being treated but this must be done quickly as the calcium bicarbonate solution is super saturated both WRT CO2 and CaCO3. Over time CO2 will come out (in bubbles if enough pressure was applied) and chalk will precipitate. Again calculation of the added calcium hardness in simple and depends on the amount of CaCO3 effectively added (e.g. if you put 200 mg CaCO3 into 4 liters of water and dissolve and then add 2 of those liters to your water you have effectively added 100 mg/L) CaCO3 to your water, the final volume and the pH of the final (mixed) volume. As I have given the formula in at least 2 recent posts, I will not repeat it here.

If time is not of the essence you can suspend CaCO3 in water and bubble air through it. Air contains a wee bit of CO2 and will dissolve chalk to the extent of 50 ppm as CaCO3 alkalinity. In this case, an excess of chalk is suspended and it will not all dissolve. The idea is to get the system into equilibrium. In a system in equilibrium with CO2 and CaCO3 the alkalinity, pH and hardness are controlled by the partial pressure of CO2. Increasing that will increase the amount of alkalinity and hardness. If, for example, 25% beer mix were bubbled through and the container covered so that the gas over the liquid is in equilibrium with the beer mix, we would obtain 561 ppm alkalinity and 568 ppm calcium hardness (both as CaCO3) at 20 °C. Just by increasing the temperature to 40 °C that can be reduced to 395 ppm alkalinity and 400 ppm hardness.

So it's possible to control akalinity to almost any level desired but the nagging question is "Is it worth it?" That, of course, depends on why you are doing it. If you are brewing a dark beer with available low alkalinity water and the pH goes low then you need to raise it. It seems, in such a case, much simpler to add some calcium carbonate to the mash (or some other salt or base) than to go through the elaborate procedure with CO2.

Now here I'll wax philosophical. You need base because you need to neutralize the acid from dark malts which the original brewer of the style had to use to neutralize base in his water. Therefore, you shouldn't need to add more base than was in the original water. Water at equilibrium with the CO2 in air and chalk will be at about 50 ppm as CaCO3. Surface water usually is not higher in alkalinity than 80 - 100. Waters of higher alkalinity probably came from wells the point being that these waters were likely supersaturated (CO2 and CaCO3). If this was, indeed, the case, then as soon as the water was heated chalk would drop and the alkalinity would go down. I can attest from personal experience that if I go to the trouble to prepare Burton synthetic water using the CO2 method that this is the case as soon as the heat is turned on in the HLT. OTOH chalk is not dropped when water of alkalinity and hardness of under 100 are heated (unless nucleation sites and excess calcium are added). So the straw man thesis here is that no beer that evolved into a style that survived was brewed with water more alkaline than about 100 and that, therefore, no more than 2 mEq/L acid from dark malts was ever used to combat it and that, therefore, you should never need more than 2 mEq/L base in brewing a dark beer whose dark malt component is based on a traditional style. A related statement is that it isn't sufficient to know what (e.g) Burton water is like but that one must know how the brewers at Burton treated it. If they doughed in cold, the alkali would precipitate out in the mash. If they heated the water first it would be left behind in the HLT. I'm guessing it was the latter but I am guessing. It is a waste of time to add the minerals necessary to provide the alkalinity of Burton water as they are coming back out as soon as the water (or mash made with it) is heated. What I'm coming to is that I suspect that if you require more than 2 mEq/L alkalinity you are using more dark malt than you should if you are trying to emulate one of the common styles. That much alkalinity can be had from 2 mmol/L NaHCO3 which would contribute 44 mg/L sodium. Not too much except in cases where the base water is already high in sodium. In fact I suspect that if you need more than 1 mEq/L you are using too much dark malt. This conclusion is bolstered by the results of my own brewing in which even fairly dark beers (most recently a barley wine at 30.7 SRM and a stout at about 70) require acid when using water with alkalinity below 1 mEq/L.

Now if you wanted to brew beer near Wadi El Natrun (or some other alkali flat) you would have much higher alkalinities than 2 mEq/L to deal with and much more dark malt would be required to deal with it. But AFAIK no style we emulate today originated in a place like Wadi El Natrun (yes, Stella is bad beer but not that bad). But as a home brewer you are, of course, free to do anything you like e.g. brew an Irish stout with 40% roast barley instead of the traditional 10%. In such a case you would need lots more alkalinity than normal and in such a case I think you will just have to bite the bullet and add alkali. Calcium carbonate is problematical because it reacts slowly - not because it is a weak base. It is, technically, a weaker base relative to calcium hydroxide or lye or potassium hydroxide but with respect to bringing mash pH to 5.4 or thereabouts each adds the same number of mEq alkalinity per mEq of the base added (slightly less for bicarb/carb but only a few %).

Finally, WRT witholding calcium - yes, should work but calcium is not that powerful an acidifying agent. 100 mg/L calcium only swings pH 0.12 units. In addition to which WRT the Burton example I strongly suspect that the calcium level that went into the mash tun was not more than about 1 mEq/L because of precipitation.
 
I have NaOH on hand for making lye dipped pretzels. My past 2 mashes I've adjusted my PH up with it. The first time I used 1/4 tsp in my 5 gallon batch and it was a much larger jump than I expected. The second time I just added an eighth at a time till my PH was where it needed to be.

It's not a practical solution for most people, but I had the stuff on hand and am familiar with handling it so it worked nicely for me.
 
I went down the same road of removing calcium from the mash, but you actually still want around 50 PPM in the mash itself for alpha-amylase stability and mash efficiency, so if you have too little calcium, you're also causing problems for yourself.

I'm going to try calcium hydroxide (pickling lime) in my next batch.
 
ajdelange:

My water is very soft. It measures at ~5.5 pH with colorpHast strips at room temperature. If Braukaiser is correct that those strips have a systematic error of 0.3, my water starts at 5.8 pH. I've measured with two other (cheaper) strips with pretty much the same results. My terrible mash efficiency since starting to use this water at my new house would indicate that the pH is correct.

If I brew anything above ~12-14 SRM, I have to start adding quite a bit of calcium bicarbonate and sodium bicarbonate to get the pH up to 5.2.

It's been plaguing me ever since I moved to Rhode Island (I've been brewing for over a decade and this is the first time I've had low pH problems with anything below ~25-30 SRM).

I've started steeping virtually all 100+ Lovibond grains and put almost exactly 50 PPM Calcium in the mash to mitigate acidification.

Even doing this, my pH needs to be at least adjusted with chalk/baking soda, and I get to a point at which I become uncomfortable adding more salt.

Hence the desire to try something more extreme like adding calcium hydroxide.

Any other suggestions are more than welcome because I'm all out of ideas.
 
I rather suspected this would be the response. In Kai's experiments the strips he tested showed a bias of about 0.3 but I've seen others post discrepancies between strip readings and pH meter readings larger than that. Always low.

The only clue I've got as to what is happening is that a gentleman here posted a picture of the strip he had immersed in wort and the bottle with the legend. The color of any pixel is easily measured on a Mac (and probably also a PC) and so I thought I could measure his test strip, interpolate between patch colors and come up with a more accurate pH estimate (I'm color blind so this is my only option). What I found was that the color of his test strip did not lie between the colors of the swatches on the legend. Little surprise, therefore, that we can't read pH with these. Strips stained with wort appear to lie in a different part of the color space than the legend.

In any event I am guessing that if you obtain a pH meter and use it to check mash you will find that you do not need to add alkali except for very dark beers. The strips have lead more than just you down this path.
 
Hop: I'm sorry that you're having that much trouble. As AJ says, you don't want to add any more alkalinity than necessary and you're trying to follow that advice. But your measurement method might be letting you down.

Do you know your water profile and have you tried a program like Bru'n Water? That will get you in the ballpark if you are weighing your mineral additions carefully. A program like that might be a better alternative to pH strips, but a calibrated pH meter is the best check.

I do like the option of reserving your roasted grain to keep the pH up. It works well. You can also consider reserving the crystal malts too if the pH is not meeting your target. Right now, I'd say that the strips might not be giving you good information and that is going to be an impediment.
 
The water pH as reported by my local water supplier is actually 5.7, which corroborates what I see when measuring tap water at room temperature (a colorpHast measurement of ~5.5 + 0.3 systematic error). My water is very soft (everything in it is quite low) with a crazy low pH and alkalinity listed as 12 mg/l.

I'm pretty sure all of this madness is reality.

I've used the same strips for years and only started having the low pH numbers after moving to Rhode Island less than a year ago.

I tried just letting it sit or adding a few salts for alkalinity and the pH always read low and efficiency was terrible. I upped the salts considerably and the pH got a little higher (as did efficiency), but it's still too low (mash efficiency is still below 70% and I used to hit closer to 80% with my other water).

That's why I'm now looking for more extreme solutions like calcium hydroxide.

I brewed a 14 SRM beer and got bad efficiency and low pH readings with 1 tsp of calcium carbonate and 1 tsp of sodium bicarbonate. It's insane! I also brewed a 28 SRM beer with similar results (and needed more brewing salts for the same fairly poor results).

I thought perhaps my thermometer was off in addition to the pH strips being utterly incorrect (to account for the poor efficiency), but it is still properly calibrated (212 at boiling in water, plus it is within a couple of degrees of some other thermometers I had lying around).

I've been building my water (started doing this a couple years ago) with a modified version of Palmer spreadsheet (using some things from Braukaiser and some from Bru'n Water).

At this point, I really do want to send in a sample of my water just for a final stamp from Ward Labs (when the wife lets me spend the money), but I've used nearby water reports from other homebrewers as well as data from the local water authority (and my own pH measurements and mash observations) to arrive where I am now.

My real questions at this point are:
- Will calcium hydroxide impact the flavor or otherwise negatively affect the final beer?
- How much do I need to raise the pH by some number of points (that I can use as the basis for calculations. e.g. if 1/8 tsp raises it by something crazy like 1.0 pH, that'll be useful to know beforehand so I don't overcompensate by accident)
 
Calcium hydroxide (pickling lime) is a pretty strong base and I'm very cautious in its addition. You mention teaspoon measurement and this is a chemical that this sort of measurement is not good for. The amount you might need is typically very small and under that condition, a volumetric measure could easily miss the mark. I strongly recommend using a scale that can read down to the tenths of a gram. In 5 gal of RO mash water for my batches, I might add less than a gram of lime and its a teeny amount of that powder. The exact amount varies in accordance with the grist. It would be so easy to screw that up with a teaspoon and the degree its packed (or not packed) into the spoon.

From my experience, I don't think that lime affects flavor (assuming its not overdosed). Calcium is relatively flavorless and hydroxide is flavorless. If the wort pH is overly low, the lime addition should be flavor beneficial in that the tart edge would be taken off the beer. Just be very careful, its better to have a little too low a pH than too high.

Bru'n Water has a calculation built in for using Lime. Its all based on the total acidity added by the grist and the total alkalinity added by the water. That balance is what drives mash pH.
 
The water pH as reported by my local water supplier is actually 5.7, which corroborates what I see when measuring tap water at room temperature (a colorpHast measurement of ~5.5 + 0.3 systematic error). My water is very soft (everything in it is quite low) with a crazy low pH and alkalinity listed as 12 mg/l.
The pH of the water itself is pretty much immaterial. It is especially so when the water's pH is so low. It is the alkalinity you need to look at. The nice thing about alkalinity this low is that you can look at it and forget it.


I've used the same strips for years and only started having the low pH numbers after moving to Rhode Island less than a year ago.

pH strips will only lead you astray. If you contemplate fiddling with brewing water your choices are to blindly follow the Primer or one of the spreadsheets or to buy and learn to use a pH meter. Only with the latter will you get a handle on what is actually happening.

I tried just letting it sit or adding a few salts for alkalinity and the pH always read low and efficiency was terrible. I upped the salts considerably and the pH got a little higher (as did efficiency), but it's still too low (mash efficiency is still below 70% and I used to hit closer to 80% with my other water).
The only way for me to know what is really happening to you is to be there with pH meter in hand when you brew but more than one brewer using strips has concluded that he should add alkali when in fact he should be adding acid. You should not need to add alkali to low mineral water like yours unless brewing a very dark beer using unusual amounts of dark malt.


I brewed a 14 SRM beer and got bad efficiency and low pH readings with 1 tsp of calcium carbonate and 1 tsp of sodium bicarbonate. It's insane!
Not really. Adding 5 grams of bicarbonate to 5 gal of water at pH 7 with alkalinity of 12 ppm would increase the alkalinity of that water to 168. Tossing in 5 grams of calcium carbonate would potentially raise it another 127. There simply isn't enough acid in malt to dissolve that much though so it wouldn't dissolve but your mash pH would definitely be high enough to explain a noticeable decrease in efficiency (and a dull flavored beer). Rather than alkali you probably should have added acid.


I also brewed a 28 SRM beer with similar results (and needed more brewing salts for the same fairly poor results).
Again not surprising. While you might need less or no acid for a darker beer you would most probably not need alkali at all and certainly not as much as a tsp of bicarb and a tsp of chalk.



At this point, I really do want to send in a sample of my water just for a final stamp from Ward Labs (when the wife lets me spend the money), but I've used nearby water reports from other homebrewers as well as data from the local water authority (and my own pH measurements and mash observations) to arrive where I am now.
Always a good idea.


My real questions at this point are:
- Will calcium hydroxide impact the flavor or otherwise negatively affect the final beer?

Calcium imparts a mineral like character and hydroxide a bitter one but you would not want to add enough that there is appreciable hydroxide left over. As noted above you probably do not need any but if you do it is because there is excess H+ which needs to be soaked up. In those cases
Ca++ + 2(OH-) + 2H+ ---> Ca++ + 2H2O
If there isn't excess H+ then unwanted increase in mash pH, as you have observed with chalk and bicarb, would be the probable effect you would notice.

- How much do I need to raise the pH by some number of points (that I can use as the basis for calculations. e.g. if 1/8 tsp raises it by something crazy like 1.0 pH, that'll be useful to know beforehand so I don't overcompensate by accident)

To answer that question you need to know the titratable acidity of the grist. This is hard to know exactly but 20 - 30 mEq/kg-pH is typical for base malts. Assuming 25, to move a mash of 10 kg 0.1 pH would require 25 mEq plus a bit more for the bicarbonate in the water (of which you haven't got much). The equivalent weight of Ca(OH)2 is 37 mg/mEq so you would need about 25*37 = 925 mg.

A good way to measure small quantities is to do what they do in water treatment plants: make a slurry. Add 1 gram lime to 100 cc of water and shake thoroughly to suspend the material. To measure out 250 mg measure out 25 mL of the slurry. Be sure to shake the container just before pipeting or pouring.
 
Thanks much to both of you again. If I continue to get poor efficiency after trying pickling lime (I do have a scale that can measure to 0.01 grams), I'll try the opposite direction. Maybe someone at RIFT (my local homebrew club) has a pH meter and will be willing to come to my next brew day.
 
They say wisdom comes from experiences we would not have had were we wise. Adding lime to light beers is not wise (in fact it's not wise for dark beers unless confirmed necessary by pH measurement). So if you intend to do that (add lime) the most you can hope to gain is wisdom. In order to enhance the probability of that occurring I strongly suggest that you beg, borrow or steal a pH meter and take pH readings before and after you add the lime. If you don't have a meter how will you calculate the amount of lime to add? You won't know the starting pH and you won't know the malt acidity.

You can get a decent meter for $90. Assuming $5 per pint that's 18 pints at your favorite local craft brewery. I suggest foregoing those pints and simply brewing 18 pints more in your next batch.
 
Martin and AJ,

First off, thank you for contributing so much to the brewing community. I really enjoyed reading this post. I use Bru'n Water for my calculations. I am planning on brewing an Oatmeal Stout in the near future, and I am using a basic Oatmeal Stout recipe (Jamil's). Like Hop, I also have low alkalinity (61 ppm bicarbonate; 33 RA) in my water. Bru'n Water predicts a pH of 5.1 with this recipe.

Per AJs suggestions, I should never have to add more than 1-2 meq/l of a base to my beer, or I am using too much dark malt. With this recipe and my profile, and addition of 1 meq/l of sodium bicarbonate puts me in the 5.3 range, and it only adds 23 ppm of sodium. My confusion comes from the suggestion that I might be using too much dark malt. Because Im using a tried and true recipe (Jamils) wouldn't I want to keep it the same proportions?

Secondly, if I did keep the recipe the same, would this sodium bicarbonate addition be advisable without the use of a pH meter? Judging by the last post by AJ, I sense what the answer might be, but just trying to learn as much as I can. :)

Thanks again.
 
My confusion comes from the suggestion that I might be using too much dark malt. Because Im using a tried and true recipe (Jamils) wouldn't I want to keep it the same proportions?

Secondly, if I did keep the recipe the same, would this sodium bicarbonate addition be advisable without the use of a pH meter? Judging by the last post by AJ, I sense what the answer might be, but just trying to learn as much as I can. :)

If you are using the same water that Jamil did and the same malts then you can be guided by his experience but you know I am always going to say that mash pH can only be determined by proper measurement with a pH meter.

The interesting possibilty also exists that you can control pH better than he did and get a better beer.
 
Don't worry at all about 23 ppm Na.

I recently brewed a batch of Brown Porter with the water profile from the deep wells in London that were typically used by the Porter breweries. That water has 110 ppm Na and 190 ppm Cl. I had never used water with that level of sodium or chloride and was very worried. Especially so, since that is the profile that is in the London article of the Zymurgy Brewing Water series. I had to try it!

Under the review of several National judges, the comments for that porter were very good. One said that he thought that he detected a minerally flavor. I'm not so sure the water is the only contributor to any minerallyness since the beer was fermented with WY 1028 London Ale that is reputed to produce minerally notes in beer.

With that evidence, I have no problem recommending Na in the 100 ppm range in a beer like porter or stout where the sodium actually aids the perception of sweetness. There is NO saltiness in the flavor. The typically quoted sodium level that produces saltiness is around 250 ppm.

Even John Palmer reported a similar result while playing with sodium levels in beer. In the 100 ppm range, the beer gets fuller and sweeter. So the message you should take away is that boosting Na with sodium bicarb is OK if its really needed for pH increase in the mash. I and others have noted that dark and roasty beer flavor is improved when the mash and kettle wort pH is around 5.5.

Of course, a pH this high is not recommended for dry stout. Then the kettle wort pH should be more like 5.1 or 5.2 to help create the acidic notes that are typical in that style.
 
Martin,

Some questions regarding adding roast and crystal grains at the end of the mash.

1. Which grains should be added at the end specifically? Is it all Crystal and roasted grains or just at a certain lovibond point?

2. At what point in the mash should they be added and for how long do they need to convert?

3. Wouldn't adding them at the end still drive down the overall ph of the wort?

Thanks
 
Martin,

Some questions regarding adding roast and crystal grains at the end of the mash.

1. Which grains should be added at the end specifically? Is it all Crystal and roasted grains or just at a certain lovibond point?

2. At what point in the mash should they be added and for how long do they need to convert?

3. Wouldn't adding them at the end still drive down the overall ph of the wort?

Thanks

If the mashing water alkalinity is appropriate, then there is no need or desire to reserve any grains to the end of mash. When the mashing water alkalinity is too low to buffer the addition of more acidic grains, then reserving the more acidic grains (roasted or crystal) can help the main mash pH keep up in the desirable range of 5.2 to 5.6. Either or both of those grain categories can be reserved from the main mash. The amount and which ones is dependent upon the alkalinity of the mashing water.

An example can be found in how Guinness mashed at their Royal Park brewery in London. While all the roast was reserved from the main mash at their St James Gate brewery, the Royal Park brewers did add a small portion of the roast to the main mash to help knock out the higher alkalinity of the Thames water. The same principal applies when deciding to reserve some or all of the roasted or crystal malts from the mash. You do what is necessary to produce the mash pH that you want in order to enhance the resulting wort properties.

The timing of those late additions is debatable. I believe that they should be delayed long enough to avoid the damage that low pH can inflict on the body builders in the wort. In addition, their duration in the wort prior to boiling and enzyme denaturing should be as short as possible. Since it does take time to extract the essence from the roasted and crystal malts, I'd say that it is a balancing act...avoiding too long a contact that reduces body or too short a contact that doesn't contribute those malt's essence adequately.

With the last question, you raise the biggest problem with this method. At the end, you still have to pay the piper. The overall kettle wort pH may be lower than may be ideal for beer flavor. Reserving acidic grains does serve to protect the MASH from a too low pH, but it does not protect the kettle wort from low pH. In the case of Irish dry stout, that acidic character is welcome. In other beers, it may not be welcome. The proper alkalinity in your mashing water helps set the pH in the kettle. There is no way around that problem.
 
1. Which grains should be added at the end specifically? Is it all Crystal and roasted grains or just at a certain lovibond point?

That depends on what you are trying to achieve by doing this. I assume it is to withold acid from the mash. That is not generally a good idea. Most beers need acid. If you withold it mash pH may rise too high giving an insipid beer. If you decide to do this you should (preferred) do it on the basis of test mash experiments using a good pH meter or (second best) use a spreadsheet whit lets you see the proton surfeits of each component and their sum or perhaps most practically use the latter to direct the former.

Gordon strong advises withholding the roast grains on the theory that mashing them leads to the acrid flavors one finds in coffee at the office that has sat on the burner for hours. I have tremendous respect for Gordon but do not, frankly, see how an hour at mash temperature is going to do the same thing as coffee overnight.

2. At what point in the mash should they be added..
As the goal is to insure proper pH for the conversion of the other grains the answer is to add them some time after the other grains have converted.

2. ...and for how long do they need to convert?
They don't to any appreciable extent. The crystals have already been mostly converted and most of the starch has been destroyed in the roasted grains.

3. Wouldn't adding them at the end still drive down the overall ph of the wort?

Yes, absolutely and this should be checked. Most texts (or most German ones) recommend wort pH at knockout between 5.0 and 5.2. As long as you are in that band (a bit higher seems to be OK too) the yeast will be able to put the beer pH where they want it.
 
Question: when I use 100% RO in Bru N Water, and basically match the Amber Balanced profile, using say 9 lb base and 1 lb crystal, only a few ml of lactic is need to hit a mash pH of 5.4. The resulting alkalinity is so low, it's off the RA chart. Is that OK? Or do I need to increase alkalinity with chalk (I realize poor solvency) or lime, then bring pH down further with acid/salts?

Confused as to if negative to low alkalinity is an issue.

-BD
 
No, low to negative residual alkalinity is needed for every beer. In fact, the only time the water doesn't need low alkalinity and low RA is when the grist supplies significant acidity.

Don't be alarmed with negative RA.
 
Well, alkalinity can't officially be negative. But I use "negative" bicarbonate and alkalinity as a surrogate for a surfeit of protons in the calculations in Bru'n Water. That drives AJ crazy, but it happens to work and it is valid.
 
Well, as long as you say its OK, then OK by me.

One other question (off topic but since I have you)...

On the sparge acidification tab, it calculates how much acid is needed based on the volume and pH of the sparge water. I am using only RO water, so very little acid (lactic) seems to be needed. My question is: do the salts that I am adding to the sparge water have any effect on its pH? If so, its not having any effect on that tab, and the only consideration for sparge water pH is acid addition. I assume this is correct but was hoping for validation.

-BD
 
Yes, pH is only used on the sparge acidification calculation. In addition, its effect is fairly small with respect to the resulting acid quantity.
 
I like the idea of adding brewing salts directly to the kettle after the mash, but wouldn't this lower the pH still and lower the final pH? I aim to achieve a final pH of 4.5. If I add the amount of salts I'm thinking of it'll bring the starting pH well below where it needs to be to hit 4.5. In this instance would I add chalk to the boil as well to adjust the pH?
 
Well, alkalinity can't officially be negative.
Yes, it can. If I give you a sample of water at pH 4 and ask you to measure the alkalinity of it you will have to add base to reach the usual pH of 4.5. One has the choice of expressing the addition as mEq of base in which case the proper term is 'acidity' but as acidity is usually associated with a target pH of 8.3 (P) that is confusing and it is therefore better to refer to the proton absorption as a negative proton addition and speak of negative alkalinity.

But I use "negative" bicarbonate and alkalinity as a surrogate for a surfeit of protons in the calculations in Bru'n Water. That drives AJ crazy, but it happens to work and it is valid.
As negative alkalinity makes sense and is commonplace I have no problem with it and in fact use it all the time. Where a mEq/L (+ or -) is expressed '50 ppm as CaCO3' I have a bit more of a problem as this has caused confusion for years and one often sees people assuming that it means there is calcium carbonate in their water at much higher levels than there actually is but at least it says 'as CaCO3' so anyone with even a modicum of chemistry knows what it means. This is, I think, slowly going away to be replaced by the much more sensible mEq/L but it isn't going to be gone any time soon. OTOH IUPAC deprecates the use of normality in describing the strengths of acids so who knows where we'll end up?

Now what does drive me nuts is calling 1 mEq/L proton deficit '61 mg/L bicarbonate' or 1 mEq/L proton surfeit '-61 mg/L bicarbonate'. My reasons are

1)I see questions like 'I added lime to RO water and the spreadsheet tells me I now have bicarbonate ion, WTF?' or I added lactic acid and I now have negative bicarbonate ion, WTF?' People are (rightly I think) confused by this

2)If we have a 1 mEq (50 ppm as CaCO3) surfeit of protons (from dark malts or added acid) relative to a desired pH presumably the program tells us that is -61 mg of bicarbonate. But the amount of bicarbonate we would actually have to add to 'neutralize' this surfeit and hit the target pH depends on the target pH. A few examples (mg bicarbonate - mEq and mg as CaCO3 included):

pH Bicarb mEq ppmCaCO3
4.5 61.8 1.00 50
5.0 63.5 1.00 50
5.1 64.2 1.00 50
5.2 65.0 1.00 50
5.3 66.1 1.00 50
5.4 67.4 1.00 50
5.5 69.0 1.00 50
5.6 71.1 1.00 50
5.7 73.8 1.00 50

Thus I don't think we can agree that the bicarbonate representation works or that it is valid. Note that the 'as CaCO3' representation, while it is less clear than the mEq representation works and is valid whereas the bicarbonate representation does/is not because the second pH of carbonic acid, 10.38 at room temperature is much higher than the first pK 6.38, and is, thus, farther from mash pH.

3)There is a perfectly fine unit for expressing alkalinity and acidity e.g. mEq though I'm not certain where IUPAC is on that these days. There are other perhaps more confusing but familiar units notably ppm as CaCO3, dH, °F etc. and most of them have some relevance to the chemistry involved (dH are really the same as CaCO3 but are in terms of the CaO that would be dissolved to give the same calcium level) and indeed we can choose any units we like such as °Martin or °AJ. Martin likes a unit which is 61*mEq/L. °AJ are 'as Vanadate' which is 38.3027*mEq/L. Units such as dH and ppm as CaCO3 have some relationship to something meaningful. If you have natural water (limestone dissolved by CO2) with alkalinity 100 ppm as CaCO3 you know that the source of that alkalinity was about 100 mg of calcium carbonate dissolved in water with a carbon dioxide content typical of subterranean water in mesic regions. °AJ and °Martin have, as the table above shows, no direct relationship to any useful information. They can still be used, of course, by dividing by, respectively, 38.3027 or 61 to get back to what we really need which is mEq/L.

4)I have never seen an answer to the question "What is the advantage to using bicarbonate as a proxy for alkainity/acidity?"

So ultimately, I ask again, given that there is apparently no advantage, several disadvantages, that it confuses people and that there are acceptable alternatives, why use it?
 
I like the idea of adding brewing salts directly to the kettle after the mash, but wouldn't this lower the pH still and lower the final pH? I aim to achieve a final pH of 4.5. If I add the amount of salts I'm thinking of it'll bring the starting pH well below where it needs to be to hit 4.5. In this instance would I add chalk to the boil as well to adjust the pH?

Indeed many brewers do add calcium salts to the kettle with the intention of lowering kettle pH into the desired 5.0 - 5.2 range. Others use acid. If by the final pH you mean the pH of the beer the answer is 'no- not appreciably'. The yeast will put the fermenter pH where they want it. There are, of course, limits to what they can do.
 
Yes, pH is only used on the sparge acidification calculation. In addition, its effect is fairly small with respect to the resulting acid quantity.

Started thinking about what 'fairly small' actually means. The amount of acid reqired to hit a target pH from a source pH depends, of course, on the source pH, the target pH and the alkalinity. The following chart shows how much acid is needed to get from source to target per unit of carbonate alkalinity (in other words, the alkalinity if the water itself is not included so that , for example, if your water's alkalinity is reported as 100 ppm as CaCO3 to pH 4.5, the usual endpoint, and its pH is 8 you should deduct 0.032 mEq/L for the water itself giving carbonate alkalinity of 100/50 - 0.032 to multiply by the numbers on the curves in the chart.

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Obviously the target water pH has a greater effect on the amount of acid required than source pH. It takes 0.96/0.65 = 1.48 i.e. 48% more acid to bring 7 pH source water to pH 5.05 than it does to bring it to pH 6. OTOH it only takes 11.5% more acid to bring water at pH 8.4 to pH 6 than it does water at pH 7. If the target is lower, say 5.3 then the additional requirement for 8.4 water as opposed to pH 7 water is less than 2%.
 
Could you dilute your water with purified alkaline bottled water. I believe the bottled alkaline water is 8.8ph. This is an idea I had, never tried it and don't know if it would work. Has anyone tried to do this and have success?
 
Just stumbled on this two year old question but it's a reasonable one so here's the answer. Yes, you can. The amount required will depend, of course, on the acid demand and on the alkalinity of the bottled water. It does depend some on the pH too when pH gets as high as 8.8 but one cannot determine the amount required from the pH alone.
 
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