Apr 10, 2009|

From Chris in Michigan

Dr. Brew,
I own a restaurant in Traverse City, Michigan, and use city water (which tastes very good). Yesterday I was given a sales pitch for a water softening system, and one of the points they made was about coffee. The salesperson said that if I brew coffee with soft water I can use less coffee, and it will stay fresher longer. When I asked my coffee roaster about it, he said both points were wrong, and that over- softened water can lead to brewing problems with the grounds. What is the truth and what is the fiction here?

Chris Girrbach



Quality water is a key ingredient, from your pizza dough to every beverage you serve. The quick test of your water supply is as simple as clarity, odor & taste.

If you see impurities, smell odors or the taste is offensive, don't use it for consumption. I suggest contacting your local municipality and asking for the water report for your city. They can answer many of your questions. A drip brewed cup of coffee is between 98.5 & 99% water and 1% coffee flavoring can not hide the chlorine that is placed in our water to make it potable and safe to drink. A basic water filter for sediment reduction and activated charcoal (taste & odor) will take care of most concerns. Generally, a softener system may be recommended when the mineral content is above 7 grains (1 grain = 17.1 mg/L) hardness. The most common minerals, calcium & magnesium (lime scale) can cause scaling issues within your equipment. Brewing standards of the Specialty Coffee Association of America (SCAA) recommend water in the range of 3 -6 grains (50 to 100 mg/L) for brewing coffee with the drip method.

The process of removing minerals (generally calcium & magnesium) alters the composition of dissolved solids in your city tap water by ion exchange. Tap water is passed through a resin bed charged with salt (sodium). As the calcium and magnesium ions are attracted to the resin, sodium ions are released. This alteration of the water aids in equipment maintenance by reducing scale, although it can have a detrimental impact on the coffee brewing process. The sodium ions combine with the carbonate and bicarbonate ions in the water and create a coating effect on the ground coffee particles and on the filtering media. This can result in an overflow of the filter media within the funnel. Softened water also inhibits the extraction phase of the coffee brewing process by extending brew contact time as the filter media seals over.

Should your primary brewing system be espresso, then you may want to consider a softener for that supply line. You want as little mineral content as possible for the steam tank and pressurized brew system. Do not install on your ice, soda fountain or drip coffee brewer. A previous blog post, "Soft Response", may provide additional information for you.

Happy Brewing,
Dr. Brew


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