QUESTION: Why does my coffee taste sour? I’ve been sampling expensive coffee brands lately and buying high end beans. I’ve noticed that several of them have a kind of sour taste to them. Is that correct? – Matthew S
ANSWER: An overly sour cup of coffee is a terrible thing to taste. If you can manage to stomach it just for the caffeine boost, sour coffee is an awful way to start out your day and it might not sit too well on your stomach either. There are several causes for sour coffee, including improper brewing techniques, under-extraction, bad grinding consistency, overly coarse grounds, and bad coffee beans.
In order to fully answer the question, we’ll take a look at the reasons that could be contributing to your sour joe, and give you some pro tips on how to make sure you never brew another sour batch of coffee again.
A sour note isn’t necessarily a mark of a bad cup of coffee. Some coffee, especially light roasts, have a tendency to have a pleasantly sour note. I suspect this is what’s happening with your sour coffee, because you said that you’re buying more expensive coffee beans. However, there is a big difference between a sour cup of coffee and a pungently sour cup of coffee. Trust us, you will know the difference when you taste it.
A sharp note of citrus can be an excellent feature of a top notch brew. Sourness is a characteristic of acidity, which is always present in coffee, but more prevalent in light roasts. Some roasts have an acidity level which is more forward than others, and some can even leave a sour aftertaste without being unpleasant. However, when sourness overpowers your cup, something is wrong. It is time to investigate, and find out what is causing the sourness,
Sometimes, sour coffee can be caused by bad coffee beans. Some under-roasted coffee beans can carry a sharp, sour note, and coffee beans that are old, or improperly packaged, can be incredibly stale, which can lead to a bold, citrus-heavy flavor and aroma. However, more often than not, the culprit of sour coffee is a flaw in the preparation technique.
Many of the most common brewing mistakes that can lead to sour coffee is under-extraction. Under-extraction can be caused by a variety of different things, including insufficient water temperature, inadequate brewing time, uneven coffee grounds, and coffee grounds that are too coarse. The ideal water temperature for brewing coffee is 203 degrees Fahrenheit, which is just under boiling level. However, anywhere between 195 and 205 will do the trick.
If you don’t allow your coffee enough time to brew, it may come out weak or sour. If you don’t get the water hot enough for the extraction, it may come out weak or sour. If your grinder produces a weird, choppy, uneven grind with big chunks floating around and other areas ground to a fine powder. The variation in grind size can result in an inconsistent brew.
Issues with your grinder can also lead to under-extraction, and a sour brew. Coffee that is ground too fine can cause over-extraction, whereas coffee that is ground too coarsely, can lead to under-extraction. An uneven grind can also cause a sour brew. To avoid uneven grounds and to achieve a more precise grinding, pick up a burr grinder. Burr grinders are not incredibly expensive, nor are they hard to find, but they are far and away, the most superior choice when it comes to selecting a grinder for your home coffee station.
Burr grinders crush the coffee beans uniformly to a coarse or fine consistency based on the setting, which can be set anywhere between extra fine and extra coarse depending on your needs and preferred brewing technique. Blade grinders, on the other hand, use sharp, spinning blades to shave the coffee beans. The friction caused by the slicing can heat up quickly, which can burn the grounds before you get a chance to brew them. Blade grinders also have a tough time achieving a consistent grind size.