Cocoa Husk Affect on Mash pH

[jwelch1103]

I'm in final preparations to brew a Chocolate Milk Stout beer. Finally tweaked the grain bill to get an acceptable predicted mash pH. It just occurred to me I do not know the affect, if any, that cocoa husks in the mash may have on the mash pH.

Does any one have any first hand knowledge pertaining to this issue?
If not first hand knowledge then any other ideas what may happen?
Rumors, innuendo, etc?

Grain bill for a 14 Gallon batch:
27 Lbs Simpson's Golden Promise EBC 3.9
5 Lbs Pale Chocolate Malt EBC 585
3 Lbs Patagonia crystal 190 Malt EBC 374
1.25-1.5 Lbs Cocoa Husks

going to aim for a 1.25qt/Lb mash

 

[bitteritdown]

Cocoa husks have a pH of about 5.8 which is alkaline with respect to a normal mash pH of 5.2-5.4. This might be ok in a stout with enough acidic roasted grains in the mash. Entering them into a water calculator as a grain with base malt color or very light caramel/crystal would probably be appropriate.

 

[ajdelange]

The appropriate thing to do would be to "mash" a few Oz in say a quart of warm deionized water and measure the pH. This is the DI mash pH, pHdi. Then add a small amount of acid with thorough stirring and a good wait (20 min) and measure the pH again. This measurement, pHacid is then used in the formula

a = mL_of_acid/((pHdi - pHacid)*Oz_of_husks)

to calculate the buffering of the husks. Only use enough acid to reduce the pH relative to pHdi by about half a unit. Use a dilute acid such as 10% phosphoric or lactic which has been diluted 1:9 with DI water. If you know the strength of the acid you can then calculate the mEq/pH•Oz or mEq/pH•kg which is the way we usually specify the first buffering term. This would be of interest to others here.

You then use your regular program with everything but the husks to determine how much acid is needed for the grains. Finally calculate

mL = (pHdi - pH_desired)*a*Oz_of_husks_in_mash

to determine the mL of acid required for the husks. If you did the test with diluted lactic, for example, and determine in this final calculation that you need 102 mL of the diluted acid clearly you should use 10.2 mL of the concentrate rather than preparing 102 mL of the diluted.

 

[jwelch1103]

The appropriate thing to do would be to "mash" a few...

Thank you for this info.