Fault
Grassy
A green, grassy note from extended contact with dry hops or from hops dried badly at harvest.
Also called hay, lawn clippings, vegetal hop.
What it tastes and smells like
Where it may be expected
A light grassy edge is common and accepted in very heavily dry-hopped beers, where it comes with the territory of large hop loads. Pronounced lawn-clipping character is a fault in any style.
Intensity and context decide. In the styles below a restrained version of this can be part of the character; the same character running past that is still a fault there.
If you are drinking it
A grassy note is a brewing choice gone slightly too far rather than spoilage. Harmless.
Not a safety issue. Beer’s alcohol, hop compounds and low pH make it inhospitable to organisms that cause illness.
What causes it
| Cause | Stage | How often | Who can act |
|---|---|---|---|
| Very long dry-hop contact, particularly at warm temperatures. How long is too long is less settled than brewing guidance suggests — published trials have found continued contact still doing useful work at four days — so this is recorded as a risk that rises with time rather than as a deadline. | conditioning | most common | brewer |
| Hops kilned inadequately at harvest, retaining chlorophyll character. | raw materials | occasional | brewer |
If you are brewing it
- Brewer: Limit dry hop contact to roughly three to five days, then remove the hops or transfer the beer off them. (prevents)
Where in the process this comes from
Steps that can produce this fault when they go wrong. Each links to what the step is for and how it is controlled.
- Concentrated lupulin products — Use hop products from which most of the leaf material has been removed, concentrating the resin and oil that carry flavour.
- Dry hopping — Add hops to beer after fermentation, without heat, to extract aroma compounds while adding essentially no bitterness.