Kaiser
Well-Known Member
This may be going to far for most, but last weekend I brewed a recipe that I hadn't brewed in a while and was wondering about the residual alkalinity that I should aim for to get to a pH between 5.4 and 5.5. When I weighed out the grain I also used my gram scale to weigh out a 1oz (30g) version of the grist. I ground that up with a coffee grinder and mixed it with distilled water at the targeted mash thickness and at about 75F. I then tested the pH of that mash and found that it was 5.51.
If I wanted to get to 4.5 I needed to lower the pH by about 0.6 units. And since each ppm alkalinity as CaCO2 changes the pH by about 0.0018 pH I needed to lower the RA by 33 ppm as CaCO3. Distilled water has an RA of 0 and therefore my RA target was -30..-35 ppm as CaCO3.
I did this and low and behold my mash pH ended up at 5.46 (+/- 0.02).
This might be too much geekery for many but I actually liked this idea of determining the RA target. I could have also found an RA that would get me close based on previous beers with a similar grist and then prepared to correct it in the mash but I like the idea of not having to be in a rush during mashing.
I also mashed with cold water for the test mash. It seems that the result was in line with the actual mash but I'm not sure if this will be true for all types of grain. Roasted grains may not "dissolve" properly in cold water and making a hot test mash would have been too much hassle for me.
Kai
If I wanted to get to 4.5 I needed to lower the pH by about 0.6 units. And since each ppm alkalinity as CaCO2 changes the pH by about 0.0018 pH I needed to lower the RA by 33 ppm as CaCO3. Distilled water has an RA of 0 and therefore my RA target was -30..-35 ppm as CaCO3.
I did this and low and behold my mash pH ended up at 5.46 (+/- 0.02).
This might be too much geekery for many but I actually liked this idea of determining the RA target. I could have also found an RA that would get me close based on previous beers with a similar grist and then prepared to correct it in the mash but I like the idea of not having to be in a rush during mashing.
I also mashed with cold water for the test mash. It seems that the result was in line with the actual mash but I'm not sure if this will be true for all types of grain. Roasted grains may not "dissolve" properly in cold water and making a hot test mash would have been too much hassle for me.
Kai