Water Chemistry Beginner

[porter1974]

I just received the results of my well water report. I brought it to the LHBS to ask for some help. The guy there was really obsessed with residual alkalinity (RA). He helped me work through an equation that would have me add about 2.5 grams of gypsum per gallon of water to get the RA below 1. I put that amount into the brewer's friend software. Sure enough, it got the RA below 1 and the projected mash PH to about 5.4. However, the calcium and sulfates would be super high!

I decided to reduce the amount of gypsum to 7 grams and added 5 grams of calcium chloride to 9 gallons of water. This gets the mash PH to 5.59 and keeps the sulfates much lower. The RA is 83.7.

Do I care about RA?

And doesn't the smaller amount of gypsum with the calcium chloride seem to make more sense?

 

[ajdelange]

In fact you don't care about RA. It is a concept that was ginned up to aid in the comparison of brewing waters and was never intended for more than that but, as is often the case with home brewers, it was grabbed on to as a potential holy grail for people struggling with water chemistry. Disclosure: I have to take some of the responsibility for that as I widely advocated its use for purposes for which it was not intended. Many of the first generation calculators seem to put very high reliance on it. Modern ones don't even calculate it or, if they do, only do so because they think users will want to see it. It is still useful for comparing water sources. You will find, in the equations used by modern spreadsheets or calculator, terms that are similar to RA.

As to the questions about how much of which salt to use: that will depend on what is in your water, what you are trying to brew and what materials you are trying to brew it with. In general, approaching mash pH control through mineral additions determined by monitoring RA is not the way to go. If you fuller details about what you are doing advice will cascade down upon you.

 

[porter1974]

This is the grain bill I want to use. It's for an English style IPA:

10 lb - United Kingdom - Maris Otter Pale (74.1%)
1 lb - Torrified Wheat (7.4%)
1 lb - Victory (7.4%)
0.5 lb - United Kingdom - Dark Crystal 80L (3.7%)
1 lb - Corn Sugar - Dextrose (7.4%)

My water profile:
54 ppm calcium
9 ppm sodium
14 ppm magnesium
21 ppm chloride
6 ppm sulfate
162 ppm CaCO3

It's hard to get the PH low enough using salts without ending up with too much calcium or sulfates. I am trying to avoid boiling and decanting.

Ultimately, I came up with .1 lb of acidulated malt (.7%), 8 grams of gypsum, and 5 grams of calcium chloride.

That gives me 149 ppm calcium, 137 sulfate, 92 chloride, a mash PH of 5.54 and a RA of 33.

 

[cire]

This is the grain bill I want to use. It's for an English style IPA:

10 lb - United Kingdom - Maris Otter Pale (74.1%)
1 lb - Torrified Wheat (7.4%)
1 lb - Victory (7.4%)
0.5 lb - United Kingdom - Dark Crystal 80L (3.7%)
1 lb - Corn Sugar - Dextrose (7.4%)

My water profile:
54 ppm calcium
9 ppm sodium
14 ppm magnesium
21 ppm chloride
6 ppm sulfate
162 ppm CaCO3

It's hard to get the PH low enough using salts without ending up with too much calcium or sulfates. I am trying to avoid boiling and decanting.

Ultimately, I came up with .1 lb of acidulated malt (.7%), 8 grams of gypsum, and 5 grams of calcium chloride.

That gives me 149 ppm calcium, 137 sulfate, 92 chloride, a mash PH of 5.54 and a RA of 33.

You've probably come up with the best compromise you could. You water is ideal for English styles and liquor profiles. One problem is the inability obtain liquor treatments readily available in Britain plus avoidance of the higher mineral levels commonly used there in ales.

AMS is available from most homebrew shops and used at the rate of 3ml per gallon would reduce alkalinity to a level with typical UK salt additions would achieve suitable pH readings through the brewing process.