Water is extremely important for tea and the lower the tds in water, the better a cup of tea tastes. But how about coffee? Is water as important for coffee as it is for tea? We asked Bjorn Aarts, coffee expert and owner of his own coffee-roasting factory.
“Water is pretty important for coffee. Coffee exists after all 98 percent from water. Water must be clean, free from heavy metals and have chlorine and a limited hardness.”
“At home I make my coffee manually. I filter tap water to a tds of 0, so 0 ppm. Then I add tap water to gradually increase the number of ppm to the level that is ideal for the type of coffee that I want to make. I am currently working on a coffee that is ideally drunk with water at 75 ppm. So I first filter the tap water to 0 ppm and then add tap water until 75 ppm.”
“The cleaner the coffee, the cleaner the water must be. But with less clean coffee you need heavier water. In terms of tds you can state that clean coffee should be brewed with water with a tds of 0, but then we talk about the top coffee of the world, which is only 1 promille of total production worldwide. Most coffee is not clean and is ideally drunk with water with a tds of 50-125 ppm.”
“The recipe for a good coffee depends first and foremost on it mouthfeel; the harder and therefore fuller the water, the fuller the mouthfeel. In addition, the degree of extraction is important for the recipe. How much coffee do you extract from the beans? Minerals and especially magnesium and sodium bicarbonate can help in this process.”
“So to make the ideal coffee, I first mix filtered water and tap water to get the correct ppm and then I might add magnesium and sodium bicarbonate to obtain the right extraction degree of the coffee. This sounds like a lot of work
for a nice cup of coffee, but if you know that at an auction a kilo good coffee costs between 100 and 150 euros, then you want your coffee as good as possible.”