Water profile when cold-steeping

[Michael_K]

Going to brew a RIS in the next few days. I would add some chalk to my mash to up my Calcium and bicarbonates, but I'm going to try cold-steeping the dark grains and adding them straight to the primary before pitching.

My water is low in Ca and HCO3, but I'll only be mashing the lighter grains. So what do you think - should I add chalk or not? Thanks!

 

[ajdelange]

Usually I need to see particulars of water and grain but when the question is 'should I add chalk' I don't need to as the answer is 'No' irrespective of the situation. If you want to ask 'what should I do instead' then we'd need to see what your water is like and what your proposed grist is composed of.

 

[Michael_K]

Sure @ajdelange. First my water:
Ca - 27
Mg - 7
SO4 - 59
Na - 39
Cl - 18
HCO3 - 83

Grist for a 2.5 gallon batch:
Mashing
5 lb Canadian Pale 2-Row
1.1 lb Light DME
0.5 lb Crystal 15L
0.5 lb Dark Crystal 80L
0.25 lb Biscuit
Cold-steeping
0.25 lb Chocolate
0.13 lb Roasted Barley

So what should I do instead?

 

[ajdelange]

You've got quite an assortment of malts there and as I have no specific data about the actual lots of the actual brands you are using I have to make what I hope are reasonable guesses as to the properties of those malts. Doing so the answer I come up with is 'nothing' i.e. you should get a mash pH of near 5.5 without withholding the roast grains and without adding alkali. If you do withhold the roast grains the mash pH will be higher. In complicated cases like this it is definitely best to perform a test mash and measure the realized pH.

 

[Michael_K]

OK, thanks for your help. I am still just getting my feet wet with the whole water chemistry stuff, so I appreciate your insight.