Water profile needed for Imperial Stout

[djbradle]

Here's the recipe:
https://www.brewtoad.com/recipes/impish


And my current water profile is:

Ca-9
Mg-1
Na-10.7
So4-11.3
Cl-26
Hardness-26
Alkalinity- 12.7
HCO3-15

This water has been great for lighter colored belgian ales up to an amber color although my belgian dark strongs have only done well when mutated with different yeast strains like tart and sour ones. After getting into water chemistry more I sense my need for more carbonates in the dark strongs. Now that I'm looking to do an imperial stout I know my salt additions will be mandatory if I'm going to make a tasty stout. I have Baking soda, calcium chloride, and gypsum on hand for this. My guess is to add all three with a high bicarbonate level, higher calcium level, and a balance between the chloride and sulfate. Whaddya think?

 

[djbradle]

I should add that I like the examples of imperial stouts such as Sierra Nevada's Narwhal, Founder's BFS, North Coast's Rasputin,and even baltic porters such as the Smuttynose big beer series. These certainly lack a cloying effect so a balance of the sulfates and chlorides is desired. I plan to add the cacl and caso4 into the kettle.

 

[mabrungard]

Wow, that is pretty nice water, but its not well suited to most stout brewing. More alkalinity is very desirable to help keep the wort pH from dropping too low. I've come to the conclusion that baking soda is the most reliable alkalinity producer and the sodium added with its use is generally welcome in darker beers for its flavor.

Since this is a fairly high gravity beer, I suggest that a modest level of sulfate to balance the chloride will be desirable to help dry the finish. I would not boost either of those levels very high since the water should remain firmly in the background for that beer.

 

[djbradle]

How does about 50ppm for both the chloride and sulfate sound with the RA at about 80ppm? Any problems with shooting for the 100's and higher with the RA?

 

[mabrungard]

RA is not a target. It is the resulting pH that the RA contributes to that is the target. Do what is necessary to move the wort pH into the 5.4 to 5.6 range. 50 ppm Cl is a good starting point. You might consider slightly more SO4 if you want a drier perception in the finish, but you are OK where you are.

 

[ajdelange]

As it turns out the acidities of your colored malts just balance the alkalinity of your base malt at pH 5.51 (I can't predict that accurately but am putting the 2nd decimal place there so you can see how much things change when we try other things) assuming that you are using Crisp's Maris Otter. There is some weirdness with Munton's Maris Otter, however, so if you use that you would probably measure a mash pH closer to 5.62 at room temperature. That's getting up there but the weirdness is that at 50 °C the pH's with the two malts would be much closer to each other (around 5.26) so if you do use Muntons don't be too concerned about high room temperature mash pH (within reason). I think 5.51 is a perfectly respectable mash pH for a stout but if you want a lower one you will have to add some acid. You might well want to increase chloride (for body) and sulfate (for hops perception). Adding 2 grams of CaCl2 (anhydride) and gypsum to the water would increase your chloride by 73 mg/L and your sulfate by 64 mg/L (assuming mashing at 1.25 quarts/lb) and would drop the pH by perhaps 0.03 to around 5.48. Not much. If you want more you will have to get acid from somewhere. Your strongest acid malt isn't very strong so you will want phosphoric, lactic, or sauermalz. Each 0.1 decrease in pH requires an addition of 1% of the total grist weight as sauermalz. This is obviously a rule of thumb.

Your mash pH buffering is about 345 mEq/pH so if you wanted to lower pH by 0.1 you'd need 34.5 mEq of acid. Given that 10% phosphoric acid is about 1 N that would mean you'd need 34.5 mL. 88% lactic is about 12 N.

The standard caveats that go with all this are that these predictions are made based on data obtained from malt measurements made either by me or Kai Troester. Insofar as the malts you have in hand may differ from what Kai and or I measured there will be differences in the predictions. Also, since Kai was kind of the pioneer in all this we can't be sure that his measurements are as solid as more current ones (they ignore the non linear terms, for example) though indications are that they are pretty good. Given that the base malt comprises 81% of the grist it is the base malt that is most important in all this and I have measured both Crisp and Muntons Maris Otter. Indications are, therefore, that 1 standard deviation in the pH predictions ought to be about 0.05 pH. From this it is quite clear that while you might want a little acid you probably won't need it but that you certainly wouldn't want to add any alkali. As is always the case where dark malts are involved you should make a test mash and measure with a good pH meter.


As for the RA, the question is how is RA defined? The standard definition of RA is alk - Ca_hardness/3.5 and that depends only on the water. If you talk about RA in any other terms you have to tell me how it is defined. I believe a lot of these spreadsheets and calculators use the RA of the water plus the proton deficit of any added acids/bases. Since I'm not advocating adding any acids or bases the RA, under this definition, would just be the RA of the water. For a fuller explanation see #9 at https://www.homebrewtalk.com/f128/water-american-premium-lager-518296/

 

[djbradle]

Awesome info guys, thanks so much! I mash at 1.5 qt/lb since I like a more liquid mash for biab.

 

[ajdelange]

That will have an effect on the sulfate and chloride ion concentrations but not, presumably, on the pH shift attributable to calcium as, presumably, it is the reaction of the calcium however it is distributed with the malt phosphate that brings about the pH reduction.

 

[djbradle]

As these additions are intended for the kettle, my darker beers such as bsda's were getting about 75% efficiency, my lighter beers are getting +80%, and regardless of the efficiency shouldn't I target carbonates to be in the 150-300 range for this stout as well as the bsda's that aforementioned suffered because of the carbonate deficiency? I read post #9 of that thread which intends the mineral additions in the mash. Some of it is of course beyond my scope of water chemistry. I inquire based on the general info out there that high carbonates are good for darker beers. Maybe I should make sure my mineral additions are in the mash instead?

If I keep the sulfates and chlorides balanced somewhat for the stout but in the future aim to increase the mineral content for the bsda's I should dial back the sulfate to chloride and increase the carbonates, correct? I feel the carbonates hanging at 15 ppm are not enough to help the stout or my future bsda batches to accentuate the maltiness or does the sulfate/chloride ratio have more of an impact?

 

[ajdelange]

As these additions are intended for the kettle, my darker beers such as bsda's were getting about 75% efficiency, my lighter beers are getting +80%, and regardless of the efficiency shouldn't I target carbonates to be in the 150-300 range for this stout as well as the bsda's that aforementioned suffered because of the carbonate deficiency?

No, absolutely not. I'm not sure exactly what you mean by 'carbonates' but lets assume that you mean calcium carbonate. 150 mg of calcium carbonate is 1.5 moles with alkalinity of 3 mEq. Multiply that by the approximately 20L mash water and that means you are adding 60 mEq of alkalinity to your mash which, as I calculated in #6, has an approximate buffering capacity of 345 mEq/pH. 60 mEq would, thus result in a pH increase of about 1/6 pH and 300 and increase of 1/3. You are just about where you want to be at 5.5. A mash pH of 5.67 would be bad and or 5.83 would be a disaster for your beer. The good news is that if you added that much chalk (and people used to do that) only about half of it reacts during the mash period but the rest reacts later and the result was a lot of ruined beer because as I said it used to be widely thought and published that one ought to have chalk in dark beers. If anything, most of them need a little acid but the notion that a dark beer needs alkali still persists to some extent.

I read post #9 of that thread which intends the mineral additions in the mash. Some of it is of course beyond my scope of water chemistry. I inquire based on the general info out there that high carbonates are good for darker beers. Maybe I should make sure my mineral additions are in the mash instead?

We've pretty much corrected the notion that stouts require tablespoonfulls of chalk in their water or their grist. We started by saying "Don't put chalk in your water it doesn't dissolve" and the proponents responded with "OK, then put it in your mash. The acids in the dark malts will dissolve it". In the first place they only dissolve a fraction of the chalk and in the second place those acids are needed to lower the pH of the base malt. Use them up dissolving chalk and there isn't enough available to get the base malt down to proper pH. Result: ruined beer not to mention that the undissolved chalk that escapes through to the kettle and fermenter keeps pulling the pH high. The yeast can compensate for this to some extent but we want their energies devoted to making ethanol and flavor compounds - not the acid necessary to neutralize all that chalk.

If I keep the sulfates and chlorides balanced somewhat for the stout but in the future aim to increase the mineral content for the bsda's I should dial back the sulfate to chloride and increase the carbonates, correct?

You should set chloride and sulfate to levels that give you the flavor effects you want. Only experiment can determine this for you. You should not increase the 'carbonates' (add alkalinity in any form) unless you make a test mash and measure a pH below say 5.4 at room temperature. With normal base and colored malts used in normal proportions this is unlikely.

I feel the carbonates hanging at 15 ppm are not enough to help the stout or my future bsda batches to accentuate the maltiness or does the sulfate/chloride ratio have more of an impact?

As noted in #6 you can get a pH of 5.5 or so with alkalinity at the level you reported. Increasing the alkalinity will only increase pH. This is not normally desirable. Most people would want to see a slightly lower pH but would accept 5.5 as OK. Sulfate/chloride ratio has no influence on mash pH (nor much of anything else) except through its effect on calcium content and that effect is, as pointed out in #6, small. Sulfate has an effect on hops. Chloride has an effect on body, sweetness, roundness. There are two degrees of freedom, not one. The ratio doesn't tell the whole story. You must specify one of chloride or sulfate as well in which case you might as well specify chloride and sulfate and not worry about the ratio.

 

[djbradle]

Thank you for taking the time to school me on these matters ajdelange. I really appreciate it. I'm thinking too objectively when the subjective aspect of taste and flavor are really what personally matters.