Can some coffees just exhibit sour characteristics when over-extracted? I've been playing around with a Kenyan I have that was under whelming from the beginning. I figured why not mess around. I wouldn't be surprised if it was a bad roast, as it has always had a bit of vege / earthy / bean like taste to it.

So the question is, are some coffees prone to also taste sour (and potentially bitter) at the same time? I have extracted the day lights (22-23%+ ey) out of a few cups and while its a tad drying, its mostly orange juice.

Just curious. I am always trying to learn more about what I am tasting.

Yes.

Poorly roasted/ under roasted coffee will still peel paint off a bumper and abuse your tongue at high extraction levels. You're just extracting more unpleasant compounds and acids. And certainly not unheard of with a dense Kenyan that accentuates these features.

Interesting! In fact, I cracked open a few beans and the roast is definitely not even. Not remotely so.

What I also find odd is that its seems to be somewhat common from "well known" roasters. Matt Perger commented that the vast majority of roasters roasting light are under-developing. I know that is not exactly quantified, but I feel like I am wasting my money on a crap shoot.

Yes! Most definitely. I compare that with extracting lemons. The more you extract the more sour it becomes

I've experienced this as well with some Kenyan coffees. No matter the extraction level, I would get an unpleasant sour grapefruit taste. I've since had some great Kenyans, but those experiences have made me a little wary of them.

I've experience this with some other coffees too. I certainly makes it hard to understand what you are tasting when historically sour means under and bitter means over!

Its taken me years to get here, but I think I am starting to realize its common to get some lack luster roasts.

Sorry I'm bumping this thread but I agree with you and I don't particularly understand it.... Meaning, roasters are trying to push the envelope and roast very lightly to maintain origin flavors, but many times the coffee ends up being very difficult to extra properly, OR the roast just wasn't good. While I love a proper city/city+ roast, I'm really getting burnt out on sour and pretty gross cups, while wasting my $ at the same time. I'd rather have a bit darker bean that extracts easier while still having great flavors, but none of the underextraction or underdevelopment.

Dont be sorry for bumping. I think this is a relevant issue especially for newer people like myself. We read and hear all over that sour is the mark of under extraction, but in reality, not always. On one hand that makes coffee more confusing, but on the other less confusing!