Brewing the perfect cup of coffee is both an art and a science. From the beans—choosing the right ones, storing and grinding them correctly—to the brewing method—pour over, French press or standard drip—coffee drinkers have a lot of decisions to make when crafting their cups. One choice that is equally important, albeit not quite as exciting as, say, selecting the proper roast, is choosing the right water.
Conventional wisdom will tell you filtered water is your best bet, but science says otherwise. According to a study by chemist Christopher H. Hendon in the Journal of Agricultural and Food Chemistry, minerals found in tap water can greatly enhance your cup of coffee.
Depending on where you live, the water from your tap could contain a different mix of minerals, such as magnesium or sodium, which will determine whether it is hard (high in minerals) or soft (low in minerals). When coffee, which contains a ton of natural chemicals and "over 1,000 aroma compounds," mixes with hard or soft water, the results can vary tremendously.
The "sticky" chemicals in hard water can greatly enhance certain roasts by drawing out flavor. Soft water, on the other hand, which is bereft of these chemicals, won't elicit as much flavor.
It's not as simple as "hard water extracts good flavor, and soft water doesn't," however. Hendon explains that not all hard water is created equal. For example, "while high bicarbonate levels are bad, high magnesium ion levels increase the extraction of coffee into water and improve the taste." In other words, living in an area with hard water doesn't guarantee a better cup. It all depends on the chemical makeup and how it will interact with that of your coffee beans.
Unless you're a serious coffee freak, you probably aren't going to dive into the nitty-gritty of determining both your tap water's and your coffee's exact chemical composition to ensure the ideal match. Where you can start, however, is looking up the type of water in your area and choosing coffee beans that are optimal for hard or soft water. Hendon tells Business Insider that high-end coffee roasters will be able to provide guidance.
To make it even easier, go local. If you seek out locally roasted coffee, Business Insider explains, you'll find beans that have been tested with the area's tap water and have thus been developed for your tap's chemical makeup.