Chlorogenic acids have an impact on the bitter taste later on. Chlorogenic acid degradation products make up 60 – 70 % of the bitter taste in coffee. With up to 13% in raw coffee, these polyphenols play an essential role in the formation of all kinds of flavour-and-taste-active compounds in coffee.

Is coffee actually bitter?

They start to break down. And here's the thing: while chlorogenic acids are responsible for the bitterness in coffee, they aren't actually bitter. ... So light to medium roasted coffees are likelier to taste less bitter and yet still contain those classic coffee aromas and flavours that we know and love.

What is the bitter taste in coffee?

Bitter coffee comes down to two things: (1) bad beans and (2) bad brewing. If you buy low-grade, robusta species, or super dark roast beans—I'm sorry—but there's nothing to be done there. Low-quality coffee just tastes bitter, which is why we suggest buying specialty-grade beans (the highest quality grade).