Could use a little help

[monkeyman1000]

Hello, I am planning on brewing a small batch of a dark mild that is under the recipe section on here. The original brewer was Orfy. I will be treating 3.12 gallons of RO water. My grain bill is 31 oz of Marris Otter ( 3 SRM ), 8 oz of Crystal 60 and 2 oz of Chocolate ( 508 SRM ). I started with Bru'n water and my additions came out to be 0.8 grams of CaSo4, 1.5 grams of CaCl2 and 6.2 ml 10% Phosphoric acid for a room temp mash pH of 5.41. I put the same values in Brewer's Friend but the predicted room temp mash pH was 5.11. Usually these two are pretty close. Which one should I go with? Thanks in advance

 

[Hermit]

I used BF for this one an hit my numbers. That recipe has a lot of c60 and that is quite acidic. Kai did the BF calculator and this page. Check out where c60 falls in the graph.
http://braukaiser.com/wiki/index.php?title=Mash_pH_control
This was one of the brews I could do well with my pH 10.7/8 water before I knew what water chemistry was.

 

[ajdelange]

I calculate 5.08 based on some assumptions about how the malts you are using compare to malts I have measured.
Looking over the proton budget it appears that a major contributor is the calcium - not because you are using so much per liter but because you have a very loose mash (5 qts/lb).

 

[monkeyman1000]

Thanks for the feedback. Looks like I will cut back on the Acid or take it out completely.

 

[ajdelange]

You'd have to do more than that. Assuming Maris Otter to have a DI pH of 5.62 (and we've seen reports that it is something like that) with buffering characteristics similar to other light malts you would, in order to get a pH of 5.4, need to
1) Eliminate the calcium hardness altogether
2) Eliminate the phosphoric acid
3) Eliminate the black malt
4) Use no more than 0.4 lb of the 60L (assuming that your 60L is close to the one I measured).

We assume that you would not want to do #1 as you would then have no vehicle for sulfate and chloride. Assuming that you want to keep those at the levels in your post you would, to attain 5.4, need to:

1) Reduce the liquor to 1 gal (1.8 qts/lb)
2) Eliminate the phosphoric acid
3) Eliminate the black malt
4) Use no more than 0.25 lb of the 60L (11%)

Or, you could keep all the original malt amounts and the very loose mash if you eliminate the phosphoric and add 1.4 grams of sodium bicarbonate. At the more reasonable 1 gal mash water you could get by with 0.77 grams of bicarbonate (this assumes that the calcium salts are also scaled back by 1:3.12).

 

[monkeyman1000]

Thanks for the advice AJ. I do a full volume BIAB so that is why my mash is so thin. I have both baking soda and some pickling lime I could add to the mash to bring up the pH. Would one be preferred over the other?

 

[ajdelange]

I suppose the bicarb is a little easier to deal with as it is limited in how high it can carry you in pH and might be easier to obtain but it will, in the amount needed for the loose mash, add 33 mg/L sodium to your beer. To do it with lime would add 26 mg/L calcium to your beer.

 

[monkeyman1000]

Ok, thanks again for the help. I picked up the supplies today so I will see how it goes.

 

[monkeyman1000]

So I ended up using .25grams of baking soda, .15 grams of pickling lime, 1.5 grams of CaCl2 and .8 grams of Gypsum. Everything else is the same as my original post. The average of three samples taken at 60 minutes was 5.54. BF predicted 5.43. I'm happy with what I got. Thanks for the help.