Rant: That whole "light roast has more caffeine" thing is getting out of hand

My buddy Mike, who works at a shop in Portland, spent 10 minutes at a cupping last week trying to convince me that dark roast is basically decaf, and it hit me how people latch onto one fact and run with it without actually measuring anything by weight.

2 comments

2 Comments

spencerfisher1mo ago

My buddy Sarah ran into this same thing at a local coffee meetup here in Denver this past weekend. Some guy was going around telling everyone that light roast is basically a caffeine bomb and dark roast is like drinking hot colored water. Sarah actually had a scale in her bag from a baking class, so she pulled it out and weighed out 20 grams of each roast from the same bag of beans. She brewed them both the same way and handed him two cups blind, and he couldn't tell which had more kick. It was pretty funny watching him squirm when the dark roast actually tested out with a tiny bit more caffeine by weight because it's denser. People just love repeating that fact without ever thinking about how they're measuring their coffee scoop vs. actually weighing it.

avery_foster311mo ago

That 20 gram test is solid, but what nobody talks about is the roasting date. I get beans from a local roaster in Austin called Texas Coffee Traders, and I noticed their light roasts lose caffeine way faster than dark roasts as they age past two weeks. Something about the chemical breakdown during roasting might lock in the caffeine better in dark roasts over time. So if you're buying coffee from a grocery store shelf that's been sitting there for months, the light roast could actually be weaker than dark roast even by volume. It adds another layer to why that old caffeine myth doesn't hold up.