Brewing Water and Yeast
There is a misconception that our brewing water has to have calcium in it in order for the yeast to grow. Fortunately, your brewing water does not need calcium in it for the yeast to prosper. Read on to learn why.
Like most organisms, yeast evolve to survive in the environment they are given. In the case of brewing yeast, they are evolved to thrive on the conditions that malt wort provides. Fortunately, malt provides the big 3 nutrients that are the building blocks of life: carbon, nitrogen, and phosphorus. In addition, malt provides calcium and magnesium that are critical for yeast metabolism. In fact, there is more than enough calcium and magnesium supplied by the malt to adequately nourish the yeast. Therefore, our brewing water doesn’t have to include calcium or magnesium ions in it to keep our yeast happy.
However, there are reasons that you might want calcium in your brewing water. The most important reason is to help remove oxalate from your wort. Oxalate is a component in beerstone and in kidney stones. So, removing oxalate from your wort can help keep both your brewery and your ‘plumbing’ clean. 40 ppm calcium in the mashing water is typically sufficient for oxalate removal.
Another reason to include calcium in your brewing water is to aid yeast flocculation. While aiding yeast flocculation is of less concern when brewing lagers, it is an important factor in getting ales to clear in a reasonable amount of time. 50 ppm calcium is recommended in the overall brewing water to help ales clear better, but less calcium is OK for lager brewing.
The final reason that you may want calcium in your brewing water is to add flavor ions such as sulfate and chloride. In the case of delicate pale lager styles, including somewhere around 20 ppm calcium in your water can be useful in delivering enough sulfate or chloride to add enough flavor to avoid the beer from tasting bland.
While there are reasons to include calcium in your brewing water, you don’t have to worry about your yeast having enough to perform well. So, it’s OK to skip calcium salts in your water…your yeast will still perform.
