Building up RO water for Foreign Extra Stout

[CyclingCraig]

Hey all

This is my second brew using 100% RO/DI water. I have been using Bru'n water for some time now, but that has been with my existing water profile that I had tested.

Just finished installing my 5 stage RO/DI system and now I just want an extra set (Or a thousand) on my additions.

I am basing my final water profile from the "Water" book for a Foreign Extra Stout. (Last one in the chart on page 158-159 for those following along). The only thing I am low on is the RA.. which the book has at 120 to 200. I'm sitting at 70.

Please let me know what you guys think. (My MW102 pH meter should be here mid week, in time for the brew weekend for measuring my pH accurately)

Anyway, here is what my Bru'n Water output looks like:
(Remember this is 100% dilution with DI water)

 

[Yooper]

Isn't your DI water pretty much all "0"s? It shouldn't have a high level of sodium for example.

 

[ajdelange]

Given that you have a pH meter coming in you should depend on a test mash rather than a spreadsheet to tell you whether you need bicarbonate and/or lime. Whether you do or not depends to a great extent of the DI mash pH of the base malt and on the amounts and qualities (DI mash pH and buffering capacities) of the roast grains. When the meter comes in be sure to check it out using the cal and stability checks discussed in the Sticky on pH Meter Calibration and then make a test mash using about 1 lb of the grains (carefully mixed to be sure they are representative of the actual mash) and some water treated as you plan to treat the main water. It's fine to use a spreadsheet to come up with the initial treatment plan for the water but you want to verify.

 

[CyclingCraig]

Isn't your DI water pretty much all "0"s? It shouldn't have a high level of sodium for example.

Thanks Yooper..

You are correct, my DI water is all pretty much "0"s, but the Brun Water spreadsheet displays my original tap water numbers, even though I am diluting my tap water with 100% DI water. I think that is there and displayed for informational purposes when you are diluting with less than 100%

 

[Yooper]

Thanks Yooper..

You are correct, my DI water is all pretty much "0"s, but the Brun Water spreadsheet displays my original tap water numbers, even though I am diluting my tap water with 100% DI water. I think that is there and displayed for informational purposes when you are diluting with less than 100%

Yes, but I don't see the box where you put 100% DI water I guess.

 

[CyclingCraig]

Yes, but I don't see the box where you put 100% DI water I guess.

Yeah, that is on a different part of the spreadsheet:

 

[CyclingCraig]

AJ

Thanks for the feedback and thanks for the replies to my pH meter posts.

When making the "test" mash, I have a scale that measures to the .01 of a gram (That is the decimal place displayed, NOT the accuracy). but I have a calibration weight of 200g that I use to calibrate.

When measuring such small amounts (Like .048 grams) for lets say my lime additions. How accurate do I really need to be, measuring THAT SMALL of an amount is very hard to get right. Will very slight inaccuracies in weights of my salts have a dramatic effect on the pH of my test mash?

Thanks
-Craig

 

[ajdelange]

I'd suggest that you dissolve 0.5 gram of lime (slaked, picking) in a liter of (cold) water. Then each cc contains 0.5 mg which is 2*0.5/74.093 = 0.0135 mEq/cc. Use that to 'weigh' out your lime.

Let's suppose for purposes of illustration that you decide to mash 20% 600L Weyermanns Black malt with 80% Weyermanns pneumatic pils (you wouldn't, of course, use a Pils malt in a stout by I have accurate data on these two malts). You could do a test mash with 0.2 lbs of the black and 0.8 lbs of the base malt. Assuming that you want a mash pH of 5.4 you would have to absorb 5 mEq of protons from the black malt. The base malt will, in having its pH reduced to 5.4, absorb 3.6 mEq of the 5 so you would need the lime to absorb the remaining 1.4 mEq. At a strength of 0.0135 mEq/cc that would take 1.4/0.0135 = 103.7 cc of your solution.

You could proceed by adding 1 quart or 1 L warm DI water to the 1 lb mix of the two grains, stir, wait and check pH. It would come in at about 5.35. You would then add lime water in modest increments (20 cc?) and recheck pH after stirring. At around 100 cc you should get pH of about 5.4. You have determined that 1 pound of your grist requires 100*0.5/1000 = 0.05 grams of lime so that 20 lbs, for example, would require a gram. The 'exact' answer here is 0.5*20*103.7/1000 = 1.037 grams. The 3.78% error isn't going to make much difference in realized pH.

Just to make the math easier I did not add any other calcium salts to the DI water. You should do that first in your experiments.

As a matter of interest you could mix these two malts with up to 15% of the 600L without pH dropping below 5.4 based on accurate data for these two malts. You are not using these two malts and so can't really rely on this but some of the spreadsheets (which also lack solid data on your malts) seem to underestimate mash pH appreciably when dark malts are involved. That's why I advise the test mash approach where a pH meter is available.

Another note. You wouldn't need both bicarb and lime. One or the other will do and you can choose the same approach with bicarb should you prefer to use that.

Working fast here so hope I didn't make any math errors.