4.2 Water Chemistry Adjustment for Extract Brewing
Some brewing books advocate the addition of brewing salts to the brewpot to imitate the water of a famous brewing region, like the Burton region of Britain. While some salts can be added to extract-based brews to improve the flavor profile, salts are more properly used to adjust the pH of the mash for all-grain brewing. Water chemistry is fairly complex and adding salts is usually not necessary for extract brewing. Most municipal water is fine for brewing with extract and does not need adjustment. So, if you are brewing from an extract recipe that calls for the addition of gypsum or Burton salts, do not add it. The proper amount of a salt to add to your water depends on the mineral amounts already present and the brewer who published the recipe probably had entirely different water than you do. You may end up ruining the taste of the beer by adding too much. Just leave it out; you probably won't miss it.
However, if in the course of time after you have brewed several batches of the same recipe and have decided that the beer is somehow lacking, there are three ions that can be used to tweak the flavor. These ions are sodium, chloride, and sulfate. Briefly, sodium and chloride act to round out and accentuate the sweetness of the beer, while sulfate (from gypsum, for example) makes the hop bitterness more crisp. You need to know and understand the initial mineral profile of your brewing water before you start adding anything to it though. Too much sodium and sulfate can combine to produce a very harsh bitterness.
Water chemistry becomes even more important for all-grain brewing. The mineral profile of the water has a large affect on the conversion of sugars from the mash. Water reports, brewing salts and their affects are discussed more in Chapter 15 - Understanding the Mash pH. I suggest you read that chapter before you add any salts to your extract brewing.
Here are the main points to remember about water for extract brewing:
If your water tastes good, your beer should taste good.
Many odors will dissipate during the boil, but some bad tastes need to be removed via filtration or water treatment.
The addition of salts when brewing with extract is not necessary, and is not recommended until you have gained experience with the intended recipe.