What makes coffee bitter?
Coffee is a complex chemical soup, and many of its chemicals, including some that produce astringency rather than bitterness, and even some acids, have been implicated in the perception of bitterness.
Bitterness also depends on variables including the coffee variety; how it is processed and roasted; the brewing method, temperature and time; and even the chemical content of the water.
Some of the possible chemical culprits include quinic, chlorogenic, caffeic, citric, malic, lactic, pyruvic and acetic acids; 5-hydroxymethylfurfural; methyl furan; furfuryl mercaptan; trigonelline; pyrazine; thiazole; quinoline; phenylpyridine; and caffeine itself.
Man, this begs the question---how can anybody enjoy drinking this concoction; especially when all these intangible factors come into play, plus the fact that it seems to have more chemicals in it than Lindsey Lohan out on a binge.
I'll tell you my secret to the perfect cup of coffee---5 tbsps. of sugar. I've never had a bitter cup of coffee in my life. Sugar, the great equalizer. (of course I don't do this anymore with the diabetes, now the great equalizer is Diabetic Sweet)