For the first time, I adjusted the water chemistry for my Shakespeare Stout Clone. In reviewing the water report for Vancouver I saw that our water is generally good for homebrewing but a couple of items (called "contaminants" in the report) were weak.
Sulfate (SO4) was 2 to 12 ppm (parts per million) and homebrews want 10 to 50 ppm for light lagers and light beers and 30 to 70 ppm for ales and darker beers.
Calcium (Ca) was 12 to 38 ppm and homebrewing needs 50 to 150 ppm.
Magnesium (Mg) also was a little weak at 6.2 to 11 ppm with homebrews needing 10 to 30 ppm.
Simply adding gypsum (CaSO4) and epsom salts (MgSO4) corrected these issues. Plugging the numbers into BeerSmith's water chemistry tool told me I needed ½ tsp. of epsom salts and 1 tsp. of gypsum for the right balance.
Both of these I had on hand so the fix was simple.
My son, Cody said that his father-in-law routinely adds gypsum to his homebrew kettle down in Roseburg, Ore., probably for the same reason.