John Palmer has a good section or how to read your water report. Good news if you live in an area with soft water, you will have control over the mineral levels in your brewing water. If your water is hard, dilution with distilled or RO water may be required. Now you only have to figure out how much of what to add to your water to get from where you are to where you want to be. In order to adjust the ion levels in your water, the minimum you'll probably need are food-grade gypsum, measuring spoons or a scale that measures in grams and a way to calculate the various ion levels. The old-school triple beam scales are expensive, but you can get the digital version for about twenty bucks.
When trying to figure things out, I was frustrated by seeing "CaSO4" in one place, "Calcium Sulfate" in another and "Gypsum" somewhere else. Turns out they're all the same thing. Depending on your water and what you're trying to accomplish you may need all the items in the water chemistry set:
|Water Salts and Their Ions |
|Household Name||Scientific Name||Formula||Weight|
|Chalk||Calcium Carbonate||CaCO3||40% Ca||60% CO3|
|Calcium Chloride||Calcium Chloride||CaCl2||27% Ca||48% Cl2|
|Gypsum||Calcium Sulfate||CaSO4||23% Ca||56% SO4|
|Epsom Salts||Magnesium Sulfate||MgSO4||10% Mg||39% SO4|
|Table Salt*||Sodium Chloride||NaCl||40% Na||60% Cl|
The weights in the table above are important because the ions you add for water treatment can only be added in pairs. You can't just add one type of ion to the water at time... much as I would like to. In order to add Soduim (Na) you will also have to add Chloride (Cl) when you use table salt. Gypsum will give you Sulfate as SO4 and Calcium (Ca), so if your Calcium is too high and your Sulfate is still too low you may also need to use Epsom Salts to bump up the Sulfate without increasing Calcium. But then you have to worry about your Magnesium level. This can make the calculations somewhat complex.
Some homebrew software will help you with the calculations. If yours doesn't there are plenty of free download-able and online tools, or you may find that you like one of the freebies better. I like the spreadsheets available from EZWaterCalculator and John Palmer. Both Palmer and EZWater have US and Metric versions, but you'll need to scroll to the bottom of the page and look for the tiny links on the Palmer site. Watch out on the Palmer spreadsheets. He hasn't protected the cells, so you can easily wipe out a vital calculation.
One real advantage for EZWater is the availability of some third-party videos that show you how to use the tool:
Brew Water Chem - Part 1
Brew Water Chem - Part 2
Brew Water Chem - Part 3
Skip the first four minutes if the first video (intro and how to order water analysis) unless you couldn't get a report locally.
You can also find several online tools. I prefer the Brewing Water Chemistry Calculator from Brewer's Friend, but you can also find calculators at Power's Brewery, ProBrewer, and Brewer' s Lair. Brewer’s Friend is nice because it warns about minimum and maximum levels for each ion, and reports how the ion concentrations impact the flavor. Based on on of the replies, I took a look at Bru'n Water and it looks very promising. I haven't had time to do anything more than download it and open it up (it's an Excel spreadsheet) but it appears to be very thorough, and covers more aspects of brewing water chemistry than any other single tool.
The Quickie Water Chemistry Primer is handy for understanding some of the issues involved, regardless of what tools you use. And John Palmer has some great information, including the only place I've been able to find a conversion chart between grams and teaspoons for everything you might want to add. My parting advice is don't worry if you can't match a water profile exactly; and if you're going to be off, undershoot rather than overshoot.
 Ray Daniels, Designing Great Beers, 1996