You’re Using Water That’s Too Hard
A filter brew made with quality beans and the right water has a pleasant, bright juiciness. If you’re struggling to achieve this, the issue might be your water—specifically, its carbonate hardness (KH). The ideal KH for filter coffee is 40–80 mg/l CaCO₃ (ppm). If you use water with significantly higher hardness (such as tap water), your coffee will taste flat, and the differences between various coffee varieties and processing methods will be blurred. Everything will end up tasting “more or less the same.”
There are several possible solutions:
1) Filtration
Filtration can remove a significant amount of impurities and hardness, but you will still be dependent on the quality of the source water. If your water is extremely hard (500 ppm or more), filtration likely won’t be enough. You can check your local water hardness levels online.
2) Bottled Water
The easiest solution is to find bottled water that meets the recommended parameters. Check the label for the HCO₃⁻ value, as bicarbonates are the biggest contributors to alkalinity. Ideally, this should be no more than 80 mg/l.
3) Reverse Osmosis with Remineralization
Reverse osmosis removes nearly all minerals from water, and remineralization allows you to add back only those necessary for coffee brewing. However, this is a costly solution and is generally impractical for home use.
4) Lotus Minerals
Lotus minerals are added to distilled water, allowing you to customize your water composition—adding only the minerals you need in the right concentrations to make your coffee taste its best.
You’re using the wrong grinder
This one is simple: don’t use blade grinders that “chop” the coffee. Instead, use grinders with flat or conical steel burrs for a consistent grind.
You’re using low-quality coffee
You can’t make a great filter brew from bad beans—no matter how hard you try. That’s why you should always buy coffee from local roasters who prioritize quality. Like us.