Using Municipal Tap Water
For all the bottled water people drink, you'd think your tap water is gruesome, foul-tasting stuff teeming with dangerous creatures ready to kill you. A great achievement of the modern era has been the clean and safe water supply. Beats schlepping buckets from a foul well.
Can you use your municipal water for brewing? In almost all cases the answer is yes, but it might take adjustments to perfect. Excepting soft water styles, only skip the tap where you have high iron or copper concentrations. As long as the water is drinkable, you can use it. With a filter, some salts, and a little distilled water you can easily hit your mark.
Know Your Water
To start, you need your water's composition. Your standard mineral levels affect the adjustments you make. The Environmental Protection Agency mandates annual water analysis reports from suppliers. These reports are always available to the public.
The report covers your area's water sources, mineral content, bacterial loads, and disinfection and safety processes. Keep a copy with your brew library. To find your report, search online for your water company's name and “water report.”
The water district's report provides general water knowledge for your area. To gather more information in a brewer-friendly format, you can purchase testing kits from your local hardware store, but for the most accurate information, send your water out to a testing lab. Ward Labs shows you how to gather a sample.
With your report data in hand, water additions cease being mysterious. Recipes often list water additions. Once you're comfortable with water chemistry, treat those instructions as guidance. The brewer is suggesting water effects. Some recipes, even if they don't list them, assume you know a few baselines. Dark beers do best with more alkaline water. Hop-forward beers sing more with sulfate, whereas pale lagers want low alkalinity waters with more chloride.
To hit a critical water profile, reduce the amount of ions in your water by diluting or starting with distilled water. See “Reducing Bicarbonate Water” for more information on that technique.
Adding Water Salts
Your store carries powdered minerals to bump your water to the target. None of these are pure elements such as calcium or sodium, but are instead safe and common mixtures. When you plan additions, remember you're changing multiple ions at once.
Purveyors sell “Burton Water Salts,” a mix of potassium chloride, Epsom salts, and gypsum. Proponents say X teaspoons per five gallons perfectly emulates Burton on Trent water. Don't buy the hype! Figure out the correct amount of water salts to add to achieve Burtonesque levels from your water.
The table below shows how many ions come from adding one gram of each salt to five gallons of water. Add that amount to the known quantity of ions in your water.
For instance, your water has 100 ppm of calcium and 25 ppm of chloride. Adding one gram of calcium chloride to five gallons yields water with 114 ppm of calcium and 50 ppm of chloride. The real tango comes in balancing the ions. Add gypsum to increase the calcium in the mash and suddenly the sulfate is through the roof.
If the addition is too much for you, brewing software programs contain water profilers to aid your efforts. Also check online for websites that help calculate needed additions. Most of these additions are targeted for the mash.