conditioning
Dry hopping
Add hops to beer after fermentation, without heat, to extract aroma compounds while adding essentially no bitterness.
What is actually happening
- Hops in the boil lose their aroma. Heat isomerises alpha acids, which is what IBU measures and where bitterness comes from. It also drives the volatile aroma compounds off with the steam. This step is drawn only to be left behind — dry hopping happens nowhere near it.
- Hops added cold, after fermentation. At 10–20°C there is nothing to isomerise and nothing to boil the aroma away, so the contribution is aroma and flavour rather than bitterness. Added during active fermentation instead, yeast enzymes release bound aroma compounds — biotransformation, which shifts a hop’s expression rather than replacing it.
- Removed after a few days. Most extractable aroma is in the beer within two to five days, and longer contact starts pulling grassy, vegetal character instead. The costs are real: oxygen pickup, harsh hop burn at high charges, and hop creep, where enzymes carried in on the hops break down dextrin and restart fermentation.
Without heat there is no isomerisation, so the contribution is aroma and flavour rather than IBU. Contact time is short by design — most extractable aroma is in the beer within a few days, and longer contact begins pulling grassy and vegetal character instead.
Adding hops during active fermentation lets yeast enzymes release bound aroma compounds, particularly thiols. That is biotransformation, and it shifts a hop’s expression rather than transforming it.
The technique carries three real costs: oxygen pickup unless carefully managed, harsh hop burn at high charges, and hop creep — enzymes carried in on the hops breaking down dextrin and restarting fermentation.
Typical conditions
| Temperature | 10–20°C |
|---|---|
| Duration | 2–5 days |
| Scale | Used at both homebrew and commercial scale |
Ranges, not targets. These describe what is usual across the styles and breweries that use this step, and a value outside the range is a decision rather than an error.
What goes wrong here
Risks rather than certainties. This step does not cause these faults; getting it wrong can.
- Grassy — A green, grassy note from extended contact with dry hops or from hops dried badly at harvest.
- Oxidation — The universal ageing fault: oxygen degrades beer into papery, cardboard-like staleness, and dulls everything that made it good.
- Overcarbonation — Too much dissolved CO₂, from over-priming, incomplete fermentation before packaging, or contamination.
- Diacetyl — A buttery compound with a very low threshold — normally a sign of rushed fermentation, but traditional at trace levels in some Czech lagers.
Styles where this step is decisive
- New England IPA
Hazy, soft and intensely aromatic: tropical and stone fruit hop character with deliberately low bitterness and a full, juicy body.
- American IPA
The defining modern craft beer: intense citrus, tropical and resinous hop aroma over a lean malt base, finishing firmly bitter.
- West Coast IPA
The dry, clear, aggressively bitter interpretation of American IPA, built on pine and grapefruit with the malt stripped right back.
- Session IPA
IPA hop intensity at a strength you can drink several of — lean, dry and aromatic, with the malt kept minimal.
- Double IPA
IPA scaled up: more strength, more hops and more bitterness, while staying dry enough to remain drinkable.
- Black IPA
An IPA with dark malt for colour and a light roast edge, keeping full citrus and pine hop character.
- Red IPA
An IPA built on caramel and amber malt, where toffee depth sits underneath full American hop character.
- White IPA
A hybrid of witbier and IPA: wheat and Belgian yeast spice underneath American hop aroma.
- Belgian IPA
American hop intensity fermented with expressive Belgian yeast, producing pepper and fruit alongside citrus and pine.
- Cold IPA
A lean, dry IPA fermented with lager yeast at higher temperature, using maize or rice to strip body and expose hop aroma.
- Milkshake IPA
A hazy IPA with lactose and fruit added for sweetness and a fuller, creamier body.
- India pale lager
A lager hopped at IPA intensity: clean cold fermentation carrying bright American hop aroma and firm bitterness.
- American pale ale
The beer that defined American craft brewing: clean pale malt under bright citrus and pine hop character, balanced rather than extreme.
- British golden ale
A modern British cask style: pale, crisp and citrus-hopped, developed to win drinkers back from lager.
- Alcohol-free IPA
An alcohol-free beer built around heavy dry hopping, since hop aroma is added after fermentation and survives the process intact.
Questions
Does dry hopping make beer more bitter?
Barely. Bitterness requires alpha acids to isomerise, which requires heat. A heavy dry hop can contribute a small amount of perceived harshness — hop burn — but that is a different sensation from iso-alpha-acid bitterness and does not register as IBU.
Why did my dry-hopped beer over-carbonate weeks later?
Hop creep. Hops carry amylase enzymes that break down dextrin the yeast could not ferment. Any remaining yeast then ferments the new sugar, producing extra CO₂ in the package. It also regenerates diacetyl, which is why some heavily dry-hopped beers develop a butterscotch note after packaging.
Related steps and concepts
- Whirlpool hopping — The hot-side aroma technique.
- Hop creep — The refermentation risk.
- Biotransformation — What happens when it is done during fermentation.
Also at the conditioning stage
Barrel ageing · Blending · Cask conditioning · Cellar conditioning · Conditioning · Freeze concentration · Lagering
See the whole process in order on how beer is made.
Last reviewed 2026-08-16.
Evidence
What BeerHQ knows about this, and how. Every statement carries the state of the evidence behind it rather than being presented flatly as fact.
Hops carry amylolytic enzymes that break down dextrins the brewing yeast could not ferment, so heavy dry hopping can restart fermentation in the package — lowering final gravity, raising alcohol, generating additional carbon dioxide and regenerating diacetyl.
Backed by a source
Sources: Journal of the Institute of Brewing; For the Love of Hops — print