Water: Your Best Ally or Greatest Enemy?

By Ted Riggs, Riggs Water Service LLC

"In the coffee business, water can be our best ally or our worst enemy. Water can add to, or subtract from the quality of a cup of well-prepared coffee. It is important to acknowledge the effect water can have on the performance and longevity of brewing equipment.” - David Beeman, 2011

Truer words are rarely spoken. Water: it does a lot of things. It washes our clothes. It provides an environment for fish to live in. It helps make our lawns nice and green. It puts out fires. In the winter, when it freezes and falls from the atmosphere it allows us to participate in the art of catching cold and going broke while rapidly hurtling downhill to nowhere at great personal risk. Water does a lot for us and it’s pretty amazing we have all the water we need right at our fingertips wherever we need it. It is no insignificant achievement that provides you with a constant supply of clean, drinkable water at a constant pressure and volume wherever you want it…as long as you keep paying that bill.

Although the water sent to businesses and homes must meet specific safety standards for consumption, understand that less than one percent of all tap water is consumed. The great majority of municipal water is used for commercial and industrial purposes. The question of the flavor quality of the water you receive is just not a very high priority for your local municipal water supplier. Instead it is up to you, the consumer to treat the water to your own liking.  A little understanding of water processing could go a long way towards having friendlier water for your equipment and the bottom line.

Fortunately for us, much detailed study and trial…the heavy lifting so to say… in regards to coffee brewing has been going on for 50 years or so. Understanding the quality of coffee goes back to the 1950’s when MIT chemistry professor E. E. Lockhart conducted surveys to determine American preferences. The fundamentals of coffee brewing now known are critically important to the coffee industry. The widely known and used tools and resources like the Coffee Brewers Handbook and the Coffee Brewers Control Chart were based primarily on Prof. Lockharts’ scientific research when he was acting director of an organization called the Coffee Brewing Institute.

The science of coffee brewing and the understanding of water and its role in the process of brewing/extraction has become quite refined in our day and there is much info available that we can benefit from. The SCAA publication The Water Quality Handbook – Second Edition is an excellent resource. If you are in the industry, whether on the equipment tech side or on the coffee shop/café owner side, you need to read it.

The water quality parameters that we should keep an eye on to get the best out of our water in regards to equipment maintenance and product quality are:

  • Total Dissolved Solids (TDS)
  • Water (calcium) Hardness
  • Chlorine
  • Total Alkalinity

Here are some stated water quality standards from within the industry. They will vary a little depending where you are getting them from.

The SCAA Standards:

  • TDS: target standard, 120 – 150 ppm (parts per million), adequate standard, 75 – 250 ppm;
  • Hardness: 3 – 4 gpg (grains per gallon), adequate standard, 1 – 5 gpg;
  • Chlorine: 0, just ZERO;
  • Total Alkalinity: at or near 40 ppm., adequate standard, 10 – 100ppm. 
  • Brewing coffee or espresso with softened water is not recommended.

The National Coffee Association (NCA):

  • Always brew with cold, filtered or bottled water.  Do not use distilled or softened water.


  • Manufacturer of Brewing Equipment
  • TDS: Target 150 ppm. Acceptable range, Below 300 ppm.
  • Water Hardness: Target, 3 – 6 gpgAcceptable range below 18gpg. 
  • Water should never be artificially softened.

Armed with this info the next question may be: "So, now how do we get our water there?" To decide on what might be the best solution for any operations water needs a water test will give that answer. Water quality is highly variable from location to location. Not only that but mineral content of waters can vary from season to season. So testing your water once may only give you a moment in time look at what's in your water but this baseline test will give you an idea of how much and what type of processing your water could need to bring it into a specific range of constituents. Compare test results to standards.

Some locations may have relatively good water whose problems can be solved with a simple filtration system. Remember that water filters (except those specifically marked water softening) do not remove water hardness. Other locations may have more serious problems that will require special solutions. There are those who are convinced that water softeners and reverse osmosis systems with phalanxes of water filters of different types and sizes upstream and downstream must be employed to strip everything out of the water and then add their own brand of "secret sauce"—select hardness minerals—back into the water with a peristaltic pump to hit those specific TDS/hardness water numbers right on the money. Others employ systems to strip everything out of the product water...and leave it out.

Of course a part of the process of selecting a water system will always include financial considerations. A shop owner must ask themselves, "do we really need all of these filters and all this expensive equipment to get the water we need?" Another consideration is that all carbon filters must be maintained and replaced regularly. Carbon filters are rated for how many gallons for how many gallons of water they can effectively treat before the process is exhausted. As we use carbon filtration to remove the oxidizing ability of chlorine in the water, bacteria can build up within the filter.

Now all bacteria is not necessarily harmful. Indeed, bacteria is in everything, everywhere (unless you live in a cleanroom) however it is prolific in its ability to multiply so it must be kept in check. Want some real equipment problems? Try not changing out those carbon filters for a couple of years. Save a few bucks on filters, spend that and much more on removing bacterial slime from your brewer and espresso machine tanks and internal water passage ways.  

Not all coffee equipment manufacturers list specific water quality standards in their literature or on their websites. The more you look into water quality parameters for coffee brewing from different sectors of the industry the more you will realize they are all about the same and all very close to if not right on the SCAA Gold Cup Standard numbers.

Another thing you will notice...on a consistent basis...is the statement "Never use distilled or softened water for brewing." There is more than one reason for this but one of the biggest ones is sodium softened water and very low TDS waters will cause an extended brew time and over extraction of the grounds resulting in an astringent, bitter tasting brew. Another thing about very low TDS waters is that the electronic level probes inside of water storage tanks will have difficulty in their ability to sense the presence of water if the water is below 20ppm TDS. "Invisible" water will of course lead to overflowing.

This now takes us to one of the big issues between water and coffee equipment tech service. A service tech may notice significant buildup of white solids on the spray heads or heating elements of brewing equipment or even worse the espresso machine or brewer clogs up and stops working altogether. Dissolving of calcium and magnesium in natural waters makes water hard, and this is responsible for scaling, liming and other obnoxious mineral deposits on brewing equipment. So...just remove the calcium and magnesium from the water and our lives will be much easier, right? That answer would be NO. What we must deal with here is a TRADE-OFF.

How do we get our water to be the best for our coffee products flavor while processing the water in such a way that it causes the least damage to our equipment? Way, way back in the day this was known as the $64,000 question. One does not want to remove all the hardness chemicals from coffee brewing water. Calcium when balanced with chlorides and bicarbonates as well as sulfate in the water chemically react with our ground coffee beans to create the best flavor extraction. Excessive calcium causes scale build up in equipment and so a balance between coffee flavor and equipment maintenance must be determined...in other words a trade-off.

Our approach should be one of balance. The point is much study and research has gone on over the past years to provide us with an educated approach to achieve that balance. Use it to improve your product quality or ignore it and continue to pay the price poor water quality can cost.