A Craft Beer & Brewing Magazine reader recently asked us the following question:
My last beer has a sharp harsh bitter finish to it. It’s not a hoppy flavor but tastes more like a harsh tea or overdone coffee finish. What did I do wrong?
I’ll cover two possibilities. Based on your description, the most likely cause is excessive tannins, though it is also possible you used an excess of grains from the “harsh zone,” which I’ll describe in a minute.
Tannins are a form of polyphenol that naturally occurs in malted grains and is derived primarily from the grain husk. During the mashing and lautering process, some tannins are extracted from the grain husks, although in most cases the tannin level remains below the flavor threshold that most people can detect.