What’s Really Inside Hops? A Brewer’s Take on the Chemistry That Shapes Your IPA
If you love IPAs and think you already know everything about hops, think again. Understanding what’s really inside hops — and how those compounds behave during brewing — can completely change the way you design and experience hop-forward beers.
Let’s break it down.
From the Lab to the Fermenter
It all started in the late 1800s, when a chemist named Chaston Chapman began analyzing hop oils. He thought he had figured it all out. Spoiler: he hadn’t. Thanks to modern tools like gas chromatography, we now know there are hundreds of aroma compounds in hops — many of them interacting with each other in ways we’re still trying to fully understand.
And here’s the kicker: a lot of what matters most happens after the boil — in the fermenter, during dry hopping, or even during biotransformation. So yes, hops are about more than just bitterness.
Acids, Oils, and Aromas: The Hop Trinity
Let’s start with the basics:
-
Bittering acids: Alpha acids like humulone give you bitterness through isomerization. But beta acids and their oxidized forms can bring a rough bitterness or even astringency if they’re not handled right.
-
Essential oils: These are the sexy compounds that bring tropical, citrus, floral, resinous, or herbal notes — depending on the hop and the conditions. Compounds like linalool (floral/citrus) and geraniol (fruity/floral) are just the beginning. Then there are thiols like 4MMP, known for their passionfruit or blackcurrant punch, that can shine when yeast enzymes free them up during fermentation.
-
Hop formats: Not all hops are created equal. T90 pellets, cryo hops, CO2 extracts, fractionated oils, or whole cones each behave differently. Choosing the right one isn’t just about availability — it’s about understanding what kind of character you want to build into your beer and how to extract it efficiently.
The Real Takeaway
There are no shortcuts to incredible hop flavor. But there’s a lot of science you can lean on. By understanding the chemistry inside each hop — and how those compounds interact during your brewing process — you can make smarter choices, create more expressive beers, and avoid common pitfalls.
If this kind of deep-dive into hop science sparks your curiosity, I highly recommend reading The New IPA by Scott Janish. It’s a goldmine for brewers who want to dig beneath the surface and build better beers from the inside out.
📘 Recommended reading: The New IPA by Scott Janish (2019)