The First Ingredient
Better Water Equals Better Product
by David Beeman
photographs by Ness/ Pace Studio
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If you are just becoming familiar with the chemical reactions in espresso extraction and brewing, you may already know that the makeup of the water you use is your best ally or your worst enemy. The quality of the beverage and the maintenance of brewing equipment for performance and longevity depend on this water. There is considerable research in water chemistry for the specialty coffee and tea industry; however, there remains much less understanding about how to produce the right kind of water for brewing coffee and tea.
The Secret to Success
It is not our purpose here to cover the subject of water formulation and coffee extraction in any depth, but rather to emphasize that controlling the "ingredient quality" of water is often the most overlooked yet necessary fundamental when it comes to expert brewing, infusing and taste standardization. In plain language, controlling your water is the secret to your success in this industry. As the science of water moves forward, what we know for sure is that we can all end our day with a better cup of coffee or a better cup of tea.
Too Little or Too Much of a Good Thing?
Some water treatment systems remove most everything from the water. Correct treatment allows predetermined and precise amounts of minerals to remain where necessary, to achieve an excellent beverage. It is important not just to have a filtering system, but also to have a system that is configured to achieve consistency and standardization, regardless of the geographical water source. In some locations that have too little mineral content to begin with, it may even be necessary to add minerals to achieve expert formulation.
Analyze this!
Consider your source water and be aware of potential source waters' fluctuations. Geography, seasons and weather will affect your water. Water quality (what is in the water) can vary seasonally and regionally. Chlorine, the amounts of total dissolved solids, total hardness, alkalinity, pH, magnesium and iron are all critical to quality formulation in one way or another. For the most part, total dissolved solids (TDS) are charged ions that have been dissolved by contact with water. Typical dissolved solids in tap water are salts comprised of calcium, magnesium, sodium, potassium, etc. Since most of the ions are charged, the TDS content can be measured with a special conductivity meter. It is always best to have your source water analyzed by a lab so you will know your baseline water source. Consistent water testing throughout the year is money well spent.
Coffeehouse owners can adopt water formulation parameters established by experts in the field to achieve their store brand taste standard. They know to sample the city water (initially and periodically) and have it analyzed for the factors that affect coffee extraction and tea infusion (explained later).
Total dissolved solids is a measure not only of hardness, but of all the dissolved compounds in the water.
Easy to Miss the Subtlety
Remember, just as coffee varies considerably from one source to the next, so it is with water. In fact, every water supply is unique because it comes in contact with different air and soil and receives different municipal treatments. Less than one percent of the water flowing out from municipals is destined for consumption. With so much water literally poured down the drain, cities find it economically challenging to use treatment processes that produce top-quality drinking water. However, super-pure drinking water is not what we are after here. Tap water is never pure or without dissolved solids and sediment. Other than the sediment (which must be filtered out), the TDS is the starting point. Expert knowledge of the reactions involved in coffee extraction and tea infusions can produce that truly great coffee and fine pot of tea.
Water contains many chemical compounds in an infinite variety of combinations and concentrations. Some of these materials, if present in relatively large amounts, can cause unusual tastes, odors and colors. Some measured in parts per billion may cause taste distortions. These are called dissolved, or soluble, materials because they form so intimate and complete a mixture with the water that even filtration cannot separate them. These compounds in smaller amounts, measured in parts per million (ppm), comprise or contribute to a number of characteristics about water that experts look for in order to formulate it for that great cup of coffee or tea. That chemistry includes a desired range of TDS, total hardness, pH (acidity) and alkalinity. It goes without saying that chlorine (used by the municipalities to disinfect the water) is corrosive to equipment and certainly not wanted in the cup. Iron is harmful to equipment and adds bitterness to the cup.
This All Begins to Make "Sensations"
In addition to being the vast majority of the beverage, water affects the release of specific flavor-producing substances. Which flavor components are ultimately extracted will depend upon the interaction of the solvent (the water) and the solute (the coffee or tea) and the temperature at which the brewing or steeping process occurs. The coffee liquor comprises liquids, gases and dissolved solids. The gaseous substances emerge from the liquid surface as aromas, while the more solid substances often sink to the bottom of the cup.
The flavor of coffee is an extremely complex balance of many individual flavor qualities and sensations. Many of the flavor compounds that are appreciated in the beverage would be unacceptable in isolation or in too great a concentration. In most sensory literature, taste qualities are classified according to how they are perceived. Gustatory sensations are perceived by the taste buds (sour, sweet, salt, bitter) on the tongue and around the mouth. Olfactory sensations, perceived by the olfactory lobe at the top of the nasal cavity, are classified as "aromas" and "fragrances." Other mouth sensations (body, smoothness, temperature) are tactile experiences.
The flavor experience of coffee is more than the sum of these categories. Still, they can be useful in discussing how the various flavor components of coffee are extracted during the brewing process.
Physical Traits of Water and What Can Be Done
Understanding the composition of your source water will lead you to the correct steps you need to take to create the best water for representing your product. First, how does the source water look and smell? Smelly (odor), cloudy (turbidity) and over-chlorinated water most often can be controlled by carbon filtration. Iron in your sample water requires oxidation reduction followed by sediment filtration. Moderate mineral content is your goal and is necessary for enhanced extraction. Artificially low TDS may be corrosive and will have an astringent flavor quality. Remember that your digital brewer's controls may require at least 20 ppm to operate and maintain optimum performance.
High TDS or high hardness is equally undesirable, reacting adversely with the beans resulting in a salty taste and/or a clouded taste. Under high TDS or problem water conditions, experts often recommend reverse osmosis (R/O) as one of the steps in formulating your water. R/O effectively removes minerals. Later, "reformulation" allows re-introduction of desirable minerals to obtain optimum TDS levels. (See map on page 44.)
Hard, Harder, Hardest
Hardness is all about certain mineral levels found in your source water. Usually, calcium and magnesium should be considered carefully. While the right amount of calcium reacts to create beneficial flavors, high calcium will require more equipment maintenance. Magnesium hardness will have a negative effect on flavor profiles. Water's pH, total alkalinity levels and hardness react with one another to create or lessen scale potential. A pH of eight or more will increase scale. Calcium loses its solubility and falls out of solution as the water is heated. In espresso machines, this means plugged tubes and a scaled boiler, and in brewers, the heating elements usually become scaled, increasing recovery time and energy usage. The scale acts as a coating or barrier in the machines that reduces their optimum heating performance. Realize that over time, the machines will fail if the scaling issues are not controlled.
Remember an optimum level of calcium needs to be determined for excellent coffee flavor extractions and tea flavor profiles. Magnesium has a negative impact on flavor and causes black scaling and a rotten egg taste. It is therefore incumbent upon the retailer to become knowledgeable about his preferred flavor profiles and how these flavors can be achieved through water treatment, thereby protecting his brewing machinery investment.
pH (percent Hydrogen Ion) and Alkalinity
The pH measures the concentration of H+(hydrogen) or OH-(hydroxide) ions in solution. Measuring pH in a liquid can be compared to measuring a room's temperature. You will know how hot or cold the room is, but the temperature won't tell you how much heat would be necessary to make the room warmer. Using the comparison of heating a room, you could attempt to lower the pH of a liquid by adding an acid (akin to raising the temperature of a room by turning on the furnace). But, the added acidity would be consumed by total alkalinity (just as the heat initially generated would be absorbed by the volume of cold air in the room before any warmth would be felt).
What Price Success?
Owners also should expect water systems to help protect their investment. The longevity of espresso machines and coffee brewers, so critical to a shop's operation, are a direct result of controlling scale or calcium buildup on heating elements as well as controlling other contaminants. Constant, vigilant investment in the proper and timely replacement of consumables in the water formulating system via an ongoing maintenance program is cheap insurance for protecting the more expensive equipment downstream.
David Beeman is founder and chairman of Cirqua® Customized Water™. Research provided by Cristina Knapp. Comments on this article may be sent to comments@freshcup.com.
Water and Tea
