Building Water for Coffee Brewing

Water is essential in coffee making. It is not only the main ingredient but also the solvent that helps dissolve the coffee beans. It is worth noting that different types of water will react differently to the same ground coffee. As a result, the tastes and textures will differ. This is important to a homebrewer, who wishes to extract and enjoy the best possible taste from the coffee. To a professional coffee brewer, even more so.

The right type of water will ensure that the extracted taste always matches the intended coffee experience. In this article we will discuss how water is measured, how brewed coffee is measured and how you can prepare your own amazing water at home.

Total Dissolved Solids (TDS)

TDS stands for “total dissolved solids”. It is a measure of the total dissolved substances in a water solution. It is measured using a refractometer or a TDS meter in ppm (parts per million) or mg/L. To make the perfect coffee, you need water that has a TDS level of 50-150 ppm. If the TDS of the water is too high it endangers the balance and clarity of the coffee. On the other hand, a very low TDS would make the coffee brewed taste “flat. Furthermore, the TDS level of the bicarbonate present in water should not exceed 75 ppm.

TDS in coffee

TDS also reflects the level of the extraction of coffee. In simpler words, the TDS level of extracted coffee helps us understand what percentage of coffee has been extracted and thus, how concentrated (strong) or dilute (mild) the coffee is. This percentage is referred to as the “Extraction Yield”. According to popular belief, coffee tastes best with an extraction yield of 18-22%. Moreover, 25% is considered to be where the cut off value starts for specialty coffee. The higher the TDS, the stronger the coffee. As an example, Americano has a TDS value of 1-2%. In comparison, Espresso, a much stronger coffee, has a TDS value of 8–12%. The TDS level of coffee can also be increased using the following ways.

• Increasing the coffee to water ratio.
  • Using more quantity of coffee than water will yield a stronger coffee and a higher TDS.
• Using a finer grind.
  • Finely ground coffee will increase surface area making the coffee stronger. Regular sand-like textured coffee grounds will produce a higher TDS than using sea salt textured coffee grounds would.

Importance of minerals

A common term used to characterize water is total hardness, which simply means how packed with minerals the water is. Minerals help in extracting flavor from ground coffee. The two most important minerals are Magnesium and Calcium. Calcium gives a creamier flavor and texture while Magnesium increases sweetness. The collective measurement of these two minerals is called total hardness. Another type of hardness that should be known is carbonate hardness. This is the ability of the water to neutralize the acids present. An optimal 2:1 ratio of total hardness to carbonate hardness should be present to make flavorful balanced coffee. The minerals also help in maintaining the pH of the water between 6 and 8.

How to make coffee water at home

The most readily available water at home is tap water. Where it may taste good on its own, it is not always suitable for brewing coffee. Water best for making coffees can rarely be found in nature; therefore, it has to be man-made. Even bottled water that does not contain the ideal amount of TDS. This water can be made easily at home by adding specific amounts of certain minerals to pure water or water that has been treated with the process of reverse osmosis (RO). The most suitable RO water should have a TDS level between 5-8 ppm.

The minerals we need are Magnesium from Epsom salts, Bicarbonate from baking soda, and Calcium Chloride. These minerals can be found in food-grade off-the-shelf products.

To create the most suitable water for brewing a perfect cup of coffee, add the following little by little to RO water while testing with a TDS-meter.

• 33 ppm of baking soda
• 17 ppm of Epsom salt
• 22 ppm of calcium chloride

Pro tip: A major tip for the ideal brew is to avoid boiling your water. You should take the water off the stove or out of the kettle just before it boils. Fully boiling the water can deoxygenate it, making it less effective for brewing.

Lastly, if you feel that making your water by following a recipe is too much of a hassle, you can easily buy a mineral supplement. Products such as Third Wave Water can be mixed in to either reverse osmosis water (or distilled if RO is unavailable) to achieve the desired TDS level for a wondrous cup of coffee.