The Path Is Clear

A few months back I mentioned that I was planning to start brewing lager. Even though I still haven't gotten around to doing it, the decision to start has actually been quite beneficial to my brewing knowledge. It has resulted in some experimentation which has greatly increased my knowledge of the finer points of the brewing process. The main aspects of brewing I have been studying up on recently are water chemistry and mash ph, which are of course very closely linked. My main sources of knowledge have been the braukeiser wiki and the "Key Concepts in Water Treatment" document by Tony Wheeler, available from here. I also purchased a Hanna pH meter, and have learned to calibrate it correctly (it helps that I work with lab people). Here are some key concepts i have come to terms with (all based on Melbourne water supply - largely lacking in all ions important to brewing, with addition of about 75ppm Calcium plus some other ions):

1. Mash pH varies quite considerably with grist composition - darker grists produce lower ph mashes
2.  Very light grists produce mashes with pH (far?) above the desirable range of 5.2-5.4 (My recent Kolsch)
3.  Average grists producing copper coloured mashes just about hit the pH 5.4 mark. (My recent APA)
4.  Not adding gypsum as part of calcuim addition negatively affects hop character in medium to highly hopped beers. (Harsh hop character in my Brakspear Special with no gypsum addition, did not seem to affect hop character of my Rebel Rising Red, which had moderate hop levels and also received no gypsum)

Extrapolating from 2&3 above, it's possible that very dark grists may cause the pH to drop below 5.2. Wheeler claims it's better to be too low than too high, so we'll have to wait and see if this is an issue or not. I've got a Beamish clone coming up soon that will test this out.

Based on these findings, this is what I aim to change from now on.

1.  Measure pH with well calibrated meter FOR ALL BREWS.
2.  Add lactic acid to mash water for lighter coloured grists to get pH level in desirable range.
3.  Add gypsum to bring SO4 ion level into the 100-150ppm range for all hoppy beers. I just did this with my American Pale Ale and I'm keen to see how it affects the hop character. I may push even higher for the sake of experiment later on.

I should explain that I have always treated my water with about 1.5tsp of Calcium Chloride and 1tsp gypsum, but never really tried to understand why I should do this. I had a vague (and correct) idea that I definitely needed to add Calcium to my water, but didn't know any more than that. In the end I convinced myself that gypsum probably wasn't that important, but the first hoppy beer of my production line where it wasn't used had a very noticeable harsh hop character. Perhaps from something else, but I will experiment to see if it is from lack of gypsum.