Stalled Coffee Brews
A stalled brew is a percolation coffee brew whose drawdown becomes much slower than intended or nearly stops before the water has passed through the coffee bed. Pour-over brewers are especially sensitive because flow depends on the permeability of both the grounds and the filter.
The most common cause: fines migration
Very small coffee particles can move downward during pouring and lodge in filter pores or dense regions of the bed. This lowers permeability and increases hydraulic resistance. A grinder that produces many fines, especially with a dense light roast, can make the effect more pronounced.
Grind size
A grind that is too fine increases resistance throughout the bed. Going coarser is often the simplest fix, but a stalled brew is not always solved by changing the average grind size if the real problem is an unusually large fines fraction.
Agitation can move fines
Heavy stirring, aggressive swirling, high-energy pouring, or many pulse pours can redistribute particles. Agitation can improve saturation, but too much can drive fines toward the filter and slow the later drawdown.
Other causes
- Filter seated poorly against the brewer
- Airlock or blocked bypass paths in some brewer designs
- Very deep coffee beds
- Clogged reusable filters
- Excessively large dose for the brewer
- Paper filters with unusually low permeability
How to troubleshoot systematically
Keep dose and water constant, reduce agitation, and try a modestly coarser grind. If the brew still stalls, compare a different filter and examine grinder performance. If one coffee stalls much more than another at the same setting, bean density and brittleness may be changing the particle distribution.
Do not chase drawdown time alone
A slow brew can still taste excellent, and a fast brew can extract poorly. Use drawdown as one diagnostic alongside flavor and extraction consistency.
Watch: Troubleshooting a Bad Pour-Over
James Hoffmann’s pour-over troubleshooting video demonstrates practical adjustments when a brew is running badly, including situations where grind and drawdown are outside the expected range.
Our published and draft brewing library includes deeper coverage of fines and drawdown behavior. Browse brewing equipment and explore the coffee glossary.
