Residual alkalinity/pH adjustment/misc questions

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Thundercougarfalconbird

Well-Known Member
Joined
Dec 16, 2010
Messages
760
Reaction score
25
I've been hitting my water chemistry sites hard the last few days and have some less blind questions.

pH 8.1
Total Dissolved Solids (TDS) Est, ppm 133
Electrical Conductivity, mmho/cm 0.22
Cations / Anions, me/L 2.1 / 2.4

ppm
Sodium, Na 6
Potassium, K < 1
Calcium, Ca 26
Magnesium, Mg 7
Total Hardness, CaCO3 94
Nitrate, NO3-N < 0.1 (SAFE)
Sulfate, SO4-S 2
Chloride, Cl 3
Carbonate, CO3 6
Bicarbonate, HCO3 121
Total Alkalinity, CaCO3 109
Total Phosphorus, P 0.80
Total Iron, Fe 0.01

When calculating residual alkalinity is the alkalinity listed above the measurement I need to subtract for the RA equation?((Cax7+mgx3.5)-alkalinity)

What pH is ideal for the following phases at room temp:
Mash:5.5 at room temp?
Final runnings:?
Boil:?
Sparge water?

If I boil my water how much effect can I expect it to have on the carbonates? (Looking to decrease them)

I heard about doing 1 liter mashes with distilled water to measure pH change. Can someone shed more light on this test? How can I apply it and use it for raw calculations?

I'd like to start doing acid additions when necessary. I understand different acids simply taste different. I was thinking about using phosphoric and lactic malts to adjust. Is it really as easy as adding it a mL at a time until proper pH is reached?
I found this site.
http://www.antiochsudsuckers.com/tom/
I'm curious what our resident experts think about the acid and RA spread sheets. Worth me trying to learn on or no?

I really love the way Colin breaks down info in this podcast, definitely the most enlightening thing I've heard in regards to water chemistry. (fast forward the first hour and change)
http://thebrewingnetwork.com/shows/The-Sunday-Session/The-Sunday-Session-04-16-06-Water-Chemistry-II
I'm having trouble applying all this info I've learned to my brewdays. Additional insight would be great.
 
When calculating residual alkalinity is the alkalinity listed above the measurement I need to subtract for the RA equation?((Cax7+mgx3.5)-alkalinity)

Yes, except that you have the equation wrong. It is

RA = alkalinity - (Ca/3.5 + Mg/7) = alkalinity - (Ca + Mg/2)/3.5

Kolbach (they guy that came up with RA) called (Ca + Mg/2) the 'effective hardness'.

Note that the calcium and magnesium hardnesses and alkalinity can be in mEq/L, ppm as CaCO3 (used to be the most common) or German degrees .... i.e. any units that are some multiple of the mEq/L. All three must be in the same units. The Residual Alkalinity is then in the same units.

Where Ca and Mg are expressed in mg/L as the ion they must be converted to hardness values. Ca = 50*[Ca]/20 where Ca is the hardness in ppm as CaCO3 and [Ca] is the calcium ion concentration in mg/L. For Mg it is Mg = 50*[Mg]/12.15 and if alkalinity is given in mg/L as bicarbonate alkalinity = 50*[HCO3-]/61.

I applaud your desire to understand how to calculate this things yourself as you will obtain a better understanding of what is going on than you would if you just plug numbers into a spreadsheet. Of course you can trivially make up your own spreadsheet to do these calculations.



What pH is ideal

I once attended a conference whose title was 'The pH Paradox' the paradox being that there is no ideal. With that in mind:

5.3 - 5.5 at room temp is a good range for dough in. Measure 15 - 20 minutes after strike.

It is generally held that final runnings from lauter/sparge should be at pH less than 6 and this doubtless so for infusion mashed beers that are not going to be lagered. For beers that will be lagered (especially those that have been decoction mashed) one need not be so strict as any phenols extracted will have the opportunity to coalesce and drop out in lagering.

For the boil I'd say 5 to 5.3. Toward the lower end you will get less hop bitterness extraction.

If I boil my water how much effect can I expect it to have on the carbonates? (Looking to decrease them)

Your calcium hardness is at 26/20 = 1.3 mEq/L. As a general rule you can expect whichever is limiting (calcium hardness or alkalinity, the latter of which is at 94/50 = 1.88 mEq/L) to 1 mEq/L so the answer is not much. If your goal is really decarbonation (which it usually is) then there are things you can do i.e. add additional calcium in which case you could expect to decarbonate to alkalinity levels of somewhat less than 50. There are a couple of monographs(Alkalinity Part I and Part II) on how to do this at www.wetnewf.org.

I heard about doing 1 liter mashes with distilled water to measure pH change. Can someone shed more light on this test? How can I apply it and use it for raw calculations?

Distilled water mashes (in particular the Congress mash) are used to determine things like coarse grind and fine grind extract, wort color etc. for a given malt. I think you have the 'test mash' in which a pound or less of your grist (carefully mixed so all your grains are in the correct proportions) are mashed with a small volume of water in mind. After the appropriate wait at the appropriate temperature the pH of the test mash is measured. This gives a pretty good idea as to what the pH of the full scale mash will be. If the test mash pH is high then you add acid or reduce the alkalinity of the mash water until a test mash gives a desirable pH. You then scale the acid and decarbonation processes to the full sized mash. Mash pH should be good.

I'd like to start doing acid additions when necessary. I understand different acids simply taste different. I was thinking about using phosphoric and lactic malts to adjust. Is it really as easy as adding it a mL at a time until proper pH is reached?

Sauermalz (acidulated malt) is indeed extremely simple. On does a test mash and then adds 1% by weight sauermalz for each 0.1 pH he wants to drop. Thus if a test mash (or mash) comes in at pH 5.6 and the brewer wants 5.4 he adds 2% sauermalz. This is, of course, a rule of thumb but it works, in my experience, very well.

You can use any other acid that you can obtain in food grade (lactic and phosphoric are usually available at LHBSs) but a bit more difficult to use in that you must determine roughly how much to add and then add fractions of this amount until pH settles in where you want it. The problem is that the settling in can take some time.

Were I you I would just cut my water 2:1 or 3:1 with RO and follow the guidance of the Primer while getting up to speed on brewing water chemistry.

I found this site.
http://www.antiochsudsuckers.com/tom/
I'm curious what our resident experts think about the acid and RA spread sheets. Worth me trying to learn on or no?

In general I tell people that they should 'play around' with spreadsheets to learn about causes and effects but that in making brewing decisions they should be guided by what their pH meters tell them. IOW if a pH meter reading on a test mash indicates that mash pH is high a brewer can then go to the spreadsheet and while it may predict a pH quite different from what the meter told him he can play with calcium levels, acid additions, dilutions etc. to see what it takes to reduce pH. He can then take what he has learned and apply that to his test mash. The amount of acid to be added will probably not be what the spreadsheet predicts but as the actual addition is to be added incrementally until the correct pH is found that doesn't matter.

I can't speak to the quality of the spreadsheets on this particular site (and wouldn't even if I could). Any spreadsheet that tries to model the details of the chemistry in the mashtun is going to fall short for a variety of reasons but this does not mean they can't be quite useful for the kind of broad guidance I mentioned above. Note that the acidification spreadsheet does not speak to the acidification of mash but rather only of water. If he put my equations into Excel as they are written on the website (www.wetnewf.org), and that isn't a complicated process, then that spreadsheet should be solid. The RA graph is very useful for comparing waters which was Kolbach's intent when he offered it. I note that he says that the Water Chemistry Spreadsheet is the only one that calcuates RA. This must be an old site as they all do (AFAIK) and also the New Brewer article from which the RA diagram was taken is about 20 years old.

[
I really love the way Colin breaks down info in this podcast, definitely the most enlightening thing I've heard in regards to water chemistry.
Colin is a sharp guy.
 
I'll have to translate your answer before I understand everything.

I can't get your links to work.

Yea, I like to be able to do calculations by hand before I rely on a computer program. That broadcast with Colin shed a ton of light and gave me enough vocabulary to be able to understand broad ideas and ask questions. I only have one highschool chem class under my belt, so its slow going.

Thanks for the pH estimates. That's exactly what I was looking for. I knew it was a broad spectrum but was unsure of the range especially for final runnings and boil.

Thanks for explaining the distilled mash tests. I think play with mini-mashes to practice acid calculations and response to monitoring pH.

When you say 2:1 with RO, do you mean 2 gallons of RO and 1 gallon of tap water or the other way around?

I have been using your CaCL/Acid malt technique for a while now using 80% distilled water. But I would love to be able to save a few bucks and cut back on the distilled water a bit. I haven't had any problems with your technique thus far,but I am aspiring to go pro and would love to be able to take whatever water I'm given and alter it as necessary (baby steps =P)
Are there any good books you recommend for practical application?

Edit: Thanks for your time by the way, I hadn't realized how involved with the brewing community you are until recently. =P
 
I can't get your links to work.

Not terribly surprising. It's on an old Mac Mini and we have to do the port swapping thing to get around my ISP. Unfortunately I'm up north until probably the end of Sept and won't be able to fix it until then.


When you say 2:1 with RO, do you mean 2 gallons of RO and 1 gallon of tap water or the other way around?
Yes, 2 gal of RO, 1 gal tap.

Are there any good books you recommend for practical application?
No. That's why I, and many others, are so much looking forward to John and Colin's book.

There are chapters in brewing text books but nothing comprehensive. Gordon Strong goes into how he treats water in his last book but he is in essence saying the same thing as the Primer.
 
Back
Top