I wanted to share something I found about mash ph with the community. Perhaps it is common knowledge, but to me it was a significant forehead slap.
I’ve been struggling for quite some time with mash ph not matching the ph predicted by brewing software. The difference is as much as 0.3+ in some cases. While this may not affect the finished beer in a significant way, it’s enough of a difference that I have spent time checking equipment and recipes and water alkalinity and acid concentrations and … Basically questioning what I am doing.
A recent experience with an unexpected rise in ph during the boil pointed to one of the additives. That led me to question and check the affect of some mash additives on the ph. What I discovered was for an 8 gallon full volume mash, the ph of the mash water before dough in dropped from 6.4 to 6.0 by the addition of 1/4 tsp of Brewtan-B and 2.5 g of OxBlox. Oxblox contains Brewtan-B is I understand correctly. I knew that Brewtan-B is an acid but never thought that the small amount used in the mash would drop the ph that much.
At any rate I adjusted the amount of acid based on that finding and pretty much hit the predicted value.
If you are using these in the mash, and assuming the brewing software is accurate enough that you don’t need to confirm, beware.
I have also noticed Brewtan B, OxBlox, along with ‘normal’ salts such as CaCl, and Gypsum in combination drops the pH considerably in RO water due to no/low buffering capacity.
MoreBeer states Oxblox 3D has minimal impact on pH but may lower pH levels by 0.2-0.4 in both the mash and the finished beer.
I like the brewing software out there (I’ve used Bru’n water, Beersmith and Brewfather) but I’ve not found any way to account for this in those three. I could have missed it …
Buffer capacity is key. If the water you use has a low residual alkalinity a very slight addition of base or acid can swing the pH quite a lot. Adding a bit of baking soda raises the pH, but it does improve the RA. Read the chapter on water in John Palmer’s How to brew, very informative!
Happy brewing,
Mark van Bommel
