Wednesday, December 25, 2013

Adjusting water hardness and pH of a beer mash

I had the opportunity earlier this week to work at my brother-in-law Chris's microbrewery, and it was a blast.  The day before that we had stopped by and he showed me around.  It was amazing to me that they had started from nothing not too long ago (< 1 year), and now they had a row of fermenters, grain mill, and several other pieces of equipment whose names I don't know, but I know what they do from home-brewing experience.  What was exciting for me personally was that a lot of the technology and equipment was familiar to me from grad school!  I studied surface science: how Nickel metal can catalyze chemical reactions.  We used steel chambers under ulta-high vacuum, and so we had lots of pumping systems, cooling systems, pneumatic systems, and the chambers were connected to gases via steel lines.  All of this is present at the brewery as well other equipment.  Anyway, it was great to "see some old friends" as we used to say when we'd see a familiar piece of equipment in a different setting.

The main thing we worked on was investigating the pH (acidity) of the mash.  A general recommendation is that the pH of the mash should be in the range 5.1 to 5.4 but Chris had consistently been measuring it to be 5.7.  Not a huge problem, but in the quest for better beer it seemed like a good idea to figure out what was going on.  We started discussing on the way there.  The city water was reported as being pH 8, and Chris had a pH meter and had made measurements at various locations by sampling the water there and under various conditions.  We decided to do something similar, write it all down, and then try a mini-mash and see if by adding some salts and/or phosphoric acid we get the pH into 5.1 - 5.4 range.

Edit:  pH is important because it affects the enzyme activity during the mash, and the yeast activity during the fermentation: