Wrong brewing temperature
The optimum brewing temperature is 88 to 92 degrees Celsius. Only then can the coffee aromas develop optimally. If your coffee tastes too bitter, then the set brewing temperature is too high. If your coffee is acidic, increase the temperature because the water is too cold.
Bad water quality
Whether your coffee tastes good or bad depends not least on the quality of the water used. A good mineral water is best because it is usually lower in limestone than in tap water. Alternatively, you can descale the tap water with a water filter before use. It may also be that the coffee tastes bland and can not develop flavor if the water used is too soft. The remedy here is to gently pour a very small pinch of salt into the water.
Of course, it is much more convenient to buy coffee already ground, because that saves time. However, ground coffee in the air loses its flavor after only a quarter of an hour. If it has to be ground coffee, then you should buy it only small quantities and consume in a short time. Especially important: always store your coffee in an airtight container. Incidentally, contrary to popular belief, coffee does not have to be stored in the refrigerator. On the contrary, coffee in the fridge can even accept the unwanted flavors of the food next to it.
After three to six months, coffee beans have lost much of their flavor. Buy only as much fresh coffee as you consume in a short time and not in stock.
Coffee from the discounter
Very cheap coffee has mostly been produced by the rapid roasting process. Because the coffee beans are roasted in huge drums within a few minutes at very high temperatures, the beans on the outside are brown, but inside almost raw. For the coffee to develop its full aroma, the beans must be roasted slowly and at lower temperatures. Of course, this procedure is much more complex and explains in part the higher price. But you will be rewarded with a coffee that does not taste burnt or over-acidifies your stomach.
Wrong coffee blend
If you want a stable crema on your coffee, then a pure Arabica coffee is not optimal. Better is, for example, a good Stimuli coffee, which contains a balanced proportion Robusta beans.
Too much or too little coffee powder
If coffee tastes bitter, then usually too much coffee powder was used. Eight to nine grams of coffee powder is the right dosage for a cup of coffee. If you want to cook several cups at a time, take a little less per cup. It is best to use a coffee measure that is normally calibrated for seven grams and overfill it easily – this will give you the optimum amount of coffee powder.
A wrong degree of grinding causes the coffee powder either too long or too short in contact with the water. If the contact time is too long, then your coffee will taste bitter. Too short contact time leads to a rather acidic coffee. For bitter coffee, you should set the grind a bit coarser, so that the water can run through the coffee powder faster. Finer coffee powder, however, increases the contact time with the water.