The bloom pour has one job: wet all the grounds so the CO₂ can escape.
The amount
Two to three times the coffee weight. 15 g of coffee wants 30 to 45 g of water.
Too little and part of the bed stays dry, which defeats the purpose entirely — and the dry part contributes nothing to the brew.
Too much and water starts passing through, which means you are brewing rather than blooming.
The duration
30 to 45 seconds. Watch the bed rather than the clock: when it stops swelling and the surface begins to sink or crack, the gas is out.
Very fresh coffee blooms hard and may need the full 45. Coffee over a month old barely blooms and needs no more than 30.
Should you stir
Yes. A gentle stir or swirl during the bloom does more for evenness than any pour technique afterwards. It guarantees every particle is wet.
Some people use a spoon; a swirl of the whole dripper works and disturbs the bed less.
Does it work in immersion
Yes. In a French press, add just enough water to wet the grounds, stir, wait 30 seconds, then fill. It measurably improves evenness.
When to skip it
Coffee more than two months old has nothing left to degas. Blooming it just cools the brew.
The freshness signal
A bloom that barely moves is telling you the coffee is old. That is useful information.
Last reviewed 8 August 2026