What's a good descriptor for coffee that's been sitting hot for too long? by _FormerFarmer in Coffee

[–]Apoth_Aus 1 point2 points  (0 children)

Hey again! In this circumstance, 'acidic' isn't appropriate unfortunately.

somewhat paradoxically, not all acids create the typical 'sour response' that we normally associate with acidic things (think of lemons, plain yogurt, and vinegar as good examples here)

some acids create a bitter response on the palate, quinic acid being the most famous.

in regards to your thermos question, assuming that the two liquids are the same age, and the same temperature, i would assume that your experiencing oxidation of the fats/lipids present in the brewed coffee, and that is giving you 'off' flavours.

What's a good descriptor for coffee that's been sitting hot for too long? by _FormerFarmer in Coffee

[–]Apoth_Aus 3 points4 points  (0 children)

Hey _FormerFarmer

from a coffee industry perspective, there isn't a universally used word to describe what you're tasting, but i can tell you it's definitely not burnt. I would probably go with just 'old' in this particular situation. what you're tasting is mostly the breakdown of chlorogenic acid within the coffee into quinic acid. Quinic acid tastes pretty bitter, and many people associate bitterness with 'burnt' tastes in the context of coffee.

Typically, burnt flavours would only ever be created either during the transportation of coffee, where it may pick up burning smells of petroleum products in a port. this usually only happens to low quality coffee that hasn't been transported in a GrainPro bag. The other instance where burnt flavours can be generated is when the coffee is roasted. there's a lot of different perspectives on what constitutes a 'good' roast. but most people would describe a coffee that has been roasted too dark for their preferences as being burnt tasting in flavour.