My coffee has suddenly gotten worse - why is that?
Most common causes: new bean batch, clogged or dull grinder, calcified machine, changed water, or beans over 6 weeks old. Always check only one variable at a time.
Why that is
If coffee tastes different from one day to the next, even though you haven't changed anything, something has changed anyway — just not consciously. Coffee is a system of many variables, and any of them can tip the taste.
Cause 1: New bean batch. Even the same roast from the same roaster can differ slightly from batch to batch. The harvest fluctuates, the processing varies, the roast profile is adjusted. If you open a new bag and the coffee tastes different, that is often the reason. Solution: slightly readjust grind size and ratio.
Cause 2: Grinder dirty or dull. Coffee oils and fines accumulate in the burrs. After weeks without cleaning, they change the particle distribution and release rancid aromas. Solution: clean grinder with cleaning pellets or a brush, check the burrs.
Cause 3: Machine calcified. Limescale in the boiler changes the water temperature and flow. A calcified espresso machine brews unevenly and often too hot. Solution: descale according to manufacturer's instructions.
Cause 4: Water changed. Waterworks change the treatment seasonally. A new water filter or an expired filter cartridge changes the mineral content. Solution: measure water hardness and check filter.
Cause 5: Beans too old. Coffee noticeably loses aroma starting about 4–6 weeks after roasting. The delicate fruity and sweet notes disappear first, leaving bitterness and woodiness. Solution: buy fresh beans and pay attention to the roast date.
Cause 6: Ambient temperature. In summer, the grind size can effectively change because heat expands the grinder mechanism. Solution: correct grind size by half a step.
Proceed systematically: Always change only one variable at a time. First check the most obvious causes (age of beans, cleaning status of the machine), then the subtler ones (water, grind drift).
In practice at Green Wall Coffee
At Sophienstraße 27, we hear this question regularly. Our checklist for guests: check the roast date on the bag, clean the grinder, descale the machine. Often one of these three measures already solves it.
You'll find us at Sophienstraße 27 in Berlin-Lichtenberg, Monday to Friday 8am–5pm and Saturday 10am–5pm.
Further reading
In-depth article: How to Make Perfect Espresso
Related questions:
- What is underextraction and overextraction?
- Why does my coffee taste bitter?
- Why does my coffee taste sour?
Also relevant:
- Why does the coffee from my fully automatic machine suddenly taste bad? — Super-Automatic Machines
- How can I tell if coffee has gone bad? — Freshness & Storage
All questions in this topic: Problems & Troubleshooting