What's the Best Water for Coffee?

There are two key ingredients that go into making a good cup of coffee: ground coffee beans and water. You can add milk and sugar to taste, but the coffee beans and water you use to brew your coffee have a huge influence on its taste. Would something like a berkey water filter have a postive impact on the taste?

How Important is Water in Brewing Coffee?

It may come as a surprise to learn that the water used in the brew is very important and can significantly affect the taste, meaning the difference between an ordinary cup of coffee and a great cup of coffee. With the wide variety of coffee beans sourced from all over the world, we are spoiled for choice when it comes to finding a coffee that has a flavor that most suits our palate. But it is not only the coffee beans, or how they were roasted, ground or brewed that influences the flavor of coffee.

Okay, so water is an important factor to consider if you want to brew a great cup of coffee, but what type of water is best? Spring water or rain water? Distilled water, softened water or reverse osmosis? Filtered water? How do you choose? Lets narrow it down by looking at the components in water that affect the taste of your coffee, which will give us a better idea of which impurities we need to get rid of.

Now, most of us would probably assume that the less impurities water contains, the tastier the coffee will be. But this is not necessarily the case. Studies have shown that dissolved minerals, such as magnesium and calcium, present in water helps to extract the flavor from ground coffee beans, and the mineral composition of the water used to brew coffee can ultimately affect the flavor of the coffee in various ways.

Balance is Key

Tweaking the water used to brew coffee by adding minerals can prove tricky, as these minerals also contribute to limescale buildup on the kettle elements when hard water is boiled, which can end up reducing heating efficiency and even damage your equipment. On the other hand, using soft water that lacks these minerals can result in flat, bland coffee that lacks body. To achieve the best results when brewing coffee, it is clear that you need to find a balance between the two.

Plus a Sprinkling of TDS

TDS, or total dissolved solids, is a term used to describe all the elements dissolved in water, including the minerals that make water 'hard'. TDS is measured in parts per million (ppm) using a TDS meter. Water with TDS levels of 50 ppm is typically considered to be soft water, while water with TDS levels of 180 ppm is considered hard. According to the Specialty Coffee Association of America, the optimal TDS levels for brewing coffee is 150 ppm (150 mg/l), with levels ranging between 75 to 250 ppm considered acceptable.

So hopefully you now have a clearer understanding of what TDS is, how to measure TDS levels in your water, and how important it is when it comes to coffee. However, it's not quite that simple, as not all dissolved solids are equal when it comes to bringing out the flavor of coffee. The coffee's taste will be significantly influenced according to the type of hard minerals present. Studies suggest that positively charged cations can be particularly beneficial in contributing to the flavor of coffee.

Calcium and Magnesium

Both calcium and magnesium are common in tap water around the US, with calcium (which is responsible for limescale problems) typically being more prevalent. It has been suggested that both these minerals have a positive influence on bringing out the flavor of coffee.

Sodium and Potassium

Sodium tends to occur in tap water at higher concentrations than potassium. At low concentrations, sodium and potassium can both contribute to the sweetness of coffee. However, too much sodium, which is also a component of salt, can make coffee too salty. The Speciality Coffee Association of America recommends 10 milligrams of sodium per liter water used to brew coffee.

Copper and Iron

Copper and iron are metals that can leach into water from water pipes as the water flows through them. If present, these metals can give coffee an unpleasant metallic taste. It is best to filter them out.

Is Alkaline Water Good for Making Coffee?

Well not necessarily! The Speciality Coffee Association of America recommends that the pH (alkalinity or acidity) of water used to brew coffee should be between 6 to 8, with 7 (neutral) being ideal.

Carbonate, Bicarbonate and Hydroxide ions that influence the pH of water used for brewing coffee can also combine with other dissolved impurities and form scale. High levels of bicarbonate have also been found to impair the flavor of coffee.

Chlorine

According to the Speciality Coffee Association of America chlorine levels should be zero, and the acceptable range is also zero, meaning water used to brew coffee should be chlorine-free. They also suggest that water should be odor-free, although that seems pretty obvious as you wouldn't want to detract from the full-bodied aroma of freshly brewed coffee.

Sulphates

The presence of sulphates in water used to brew coffee can be problematic. Sulphates can accentuate the bitter flavor of coffee, and when it combines with calcium (calcium sulphate) it can lead to a hard crusty scale forming inside your coffee brewing equipment.

What Water Do You Use For Coffee?

Ideally, you are wanting to use water that has a mineral content that is not too low, nor too high; has a neutral pH and that is free of chlorine, sediment and odor-inducing elements. So which is the best water to use when brewing coffee?

Bottled Water?

While some coffee connoisseurs suggest bottled water is the holy grail, that is a rather impractical, expensive and not very environmentally-friendly way of getting the perfectly brewed cup of coffee. Aside from the monetary and environmental cost associated with using bottled water for coffee, bottled water typically tends to be either very rich in minerals or very low in minerals, making it either too hard or too soft for the perfect cuppa.

Reverse Osmosis Treatment?

Water treated by the process of reverse osmosis is forced through a fine membrane that removes all impurities, including minerals, from the water. While reverse osmosis is recommended for making espresso, it is not recommended for brewing coffee. The reason being that espresso machines use a different process and do not require minerals to bring out the flavor of the coffee in the same manner that brewing coffee does.

Carbon Filters

Carbon filters are capable of removing a wide range of contaminants, including sediments, heavy metals, chlorine and chloramines that are widely used in the disinfection process, and other contaminants that give water a bad taste and odor. But more importantly, while they remove the bad impurities, they do not strip minerals from the water. This means that the minerals that play an important role in drawing out the flavor from coffee are not removed. Meaning you will have a rich tasting cup of coffer that is full of flavor rather than being disappointed with a bland cup of coffee that lacks flavor and body.

Water Filters for Coffee Makers - An Addtional Filtration Method

An additional solution that can enrich the taste of our coffee is the use of water filters for coffee makers. Using a water filter also significantly reduces the frequency of descaling the coffee maker, which reduces maintenance time and potentially costs.

However, you should remember to replace those internal filters depending on the frequency of use of the coffee maker itself. It is usually recommended to replace it after about 8 weeks (2 months), however many manufacturers indicate the optimum time to use one filter. Today, a large number of coffee makers automatically signal that the filter has worn out and should be replaced.

Verdict

According to The Coffee Brewers, the flavor lies mostly within oil inside the coffee beans. These flavors are released into the water when the ground coffee beans are brewed. When preparing coffee (as apposed to espresso) the coffee grounds are steeped in boiling water. The heat together with the minerals present in the water both play an important role in extracting the flavor from the ground coffee beans. Once the steeping process is complete, the ground coffee beans are strained or filtered out, leaving the delicious beverage we call coffee.

Is purified water good for making coffee?

In order to appreciate a full flavorsome cup of coffee, there must be minerals present in the water used in the brewing process. So, purified water with a mineral content of 150-200 mg/l is recommended to effectively extract the flavors from the coffee. Soft water, lacking in minerals, such as distilled or RO water, will produce a bland and flavorless cup of coffee.

Carbon filters are arguably the best solution for delivering high quality purified water suitable for brewing the perfect cup of coffee. Carbon filters will remove all the impurities that negatively impact the flavor of coffee, while retaining the minerals that are essential for bringing out the full flavor of the coffee roast.