If you reside in a region with hard water, consider purchasing a small bottle of mineral water to use to prepare a single cup of coffee. After that, brew another coffee in the same manner, but this time with standard tap water. Anyone who has ever compared the two, from a seasoned coffee taster to an inquisitive novice, has been astounded by the quality difference. Let’s find out with Helena.
Water is an important component of a cup of coffee, accounting for roughly 90% of the volume of espresso and 98.5 percent of a cup of filter coffee. If the water doesn’t taste good, to begin with, the cup of coffee won’t either. And if the chlorine is detectable, the subsequent cup of coffee will be awful. A simple water filter jug with active carbon (such as a Brita filter) will often remove unwanted flavors, but it may not yield the ideal water for brewing coffee.
During the brewing process, water serves as a solvent, extracting the flavors from the coffee. This is where the water’s quality comes into play, as hardness and mineral content can have a big impact on how the coffee brews.
The amount of limescale (calcium carbonate) dissolved in the water is measured by water hardness, which is determined by the bedrock in the area. When you heat water, limescale comes out of the solution and forms a chalky white buildup over time. Those who live in locations with hard water experience the hassles of limescale in kettles, showers, and washing machines.
The hardness has a big impact on how hot water and ground coffee interact. Harder water appears to alter the rate at which the coffee’s solubles dissolve, essentially altering the way the coffee brews chemically. To make a broad statement, it appears that a modest level of harness is preferable, but anything from mild to hard water brews coffee poorly, yielding a cup deficient in nuance, sweetness, and depth. Additionally, having soft water is essential if you use any type of coffee machine that heats water, such as an espresso machine or a filter coffee maker. Limescale buildup will cause a machine to malfunction quickly, and many manufacturers will consider using hard water to void the warranty.
Aside from a good flavor and just a little hardness, there isn’t too much else we want in the water, but the relatively low mineral content is desirable. Manufacturers of mineral water are required to list the mineral content on the bottle and it is usually described as the total dissolved solids (TDS), or the ‘dry residue at 180°C’ (365°F).
THE PERFECT WATER
The Specialty Coffee Association of America (SCAA) publishes suggested guidelines for the perfect water for coffee brewing. The table below offers a summary.
If you want to understand the quality of your domestic water supply, contact your water supply company or look on its website, as most are obliged to publish data on the content of their water. If you can’t find this information, buy a water-testing kit from a pet shop (sold to test the water in fish tanks), which will give you accurate readings of the key elements.
CHOOSING A WATER
Although all of this information may appear to be overwhelming and complicated, it can be simplified as follows:
- Use tap water if you reside in a region with soft to moderately hard water, but filter it first to improve the taste.
- If you reside in a region with moderate to very hard water, bottled water is the best option for brewing coffee right now. Choose bottled water that is near to the aforementioned goals; supermarket own-brand waters have a lower mineral concentration than big-brand waters. While bottled water is not ideal, if you want to get the most out of your coffee, you must use water that is acceptable for brewing.