Water is generally considered “soft” if it contains 0-60 mg/L of dissolved minerals, specifically Calcium and Magnesium.
A review of New Westminster’s water quality report for November 2011 indicates that the level of dissolved Calcium and Magnesium, combined, is about 1.3 mg/L
After inquiring with Metro Vancouver, I discovered that the alkalinity as CaCo3 (Calcium Carbonate) of the water coming to New Westminster ranges from 6.3 to 11.1 mg/L. If we take the average of 8.4, we can Calculate the bicarbonate level:
(8.4/50) x 61 = 10.25 ppm HCO3 (Bicarbonate).
What does that mean? We have very soft water with low alkalinity.
Compare with Pilsen, Czech Republic, famous for it’s classic Pilsener Lager, Where the HCO3 concentration is only 3 ppm “The very low hardness and alkalinity allow the proper mash pH to be reached with only base malts, achieving the soft, rich flavour of fresh bread.” (Palmer 2006, How to Brew)
Like in Pilsen, our Bicarbonate levels fall in the range of 0-50 ppm, which is ideal for pale, base malt-only beers.
If you’ve been making great beer without worrying about all this, then great! Continue to do so! But be aware that there are options for changing your water chemistry in order to better suit certain styles of beer.
According to Papazian (The complete Joy of Homebrewing 3rd edition, 2003), “If your water contains less than 50 ppm of calcium, then the addition of 1 to 4 teaspoons (4-16 g) of Gypsum will aid the fermentation process.” Gypsum is Calcium Sulfate. 1 teaspoon of gypsum in 19 L of water will increase the concentration of Calcium ions by 64 ppm and sulfate ions by 153 ppm.
Adding sulfate can add a “crispness’ to hop bitterness (Palmer 2006)
On the other hand, Gypsum will also LOWER the pH. Because the alkalinity of our water is already low, I wonder if this is a good idea. Especially If you’re making a dark beer. Adding lots of roasted malts will lower the pH of the mash further. Calcium Carbonate or Sodium bicarbonate (baking soda) can be used directly in the mash to raise pH by adding alkalinity.
Playing with the alkalinity can be a slippery slope (pun intended). In the end, it really doesn’t have to be this complicated. Relax. Don’t worry. Have a homebrew.