Overview
- Experts now advise targeting roughly 3–6 °dH hardness—about 4 °dH as a guideline—because coffee is ~99% water and mineral balance steers flavor.
- In many German regions the tap water is harder than ideal (examples range from about 8 °dH in Bremen to around 22 °dH in Saxony-Anhalt), so users should check local values via lookup sites or test strips.
- Built‑in or table filters that reduce calcium and magnesium improve taste and slow scale buildup, offering a low‑cost first step before any hardware upgrade.
- Brew with cooler water—about 94 °C for espresso and up to 96 °C for filter—and adjust machine settings since factory temperatures are often set too high.
- Routine cleaning and descaling, including removing oils from grinders and brew groups, prevent rancid flavors; avoid fridge storage and keep beans airtight, dry and away from light, while filter‑machine ‘aroma’ modes can further boost extraction.