The bloom is when the foundations meet the recipe. Foundations gives you the why; here's the how-much and the how.
How much water to bloom with
The standard advice is "twice the coffee mass" (30g of water for 15g of coffee). That works for most fresh light-medium roasts. Two cases where you'd change it:
- Very fresh roast (under 7 days off-roast): bloom with 3x. Fresh coffee outgasses dramatically and a tight 2x can leave dry spots if the bed swells fast.
- Older roast or naturally low-CO2 (months past roast, or some processed coffees): 1.5x is enough. There isn't much gas to release; the wait is mostly to let water reach the dry grounds at the bottom of the bed.
How long to wait
30–45 seconds is the standard. Watch the surface, not the clock:
- Bubbles rising aggressively → still degassing, wait longer.
- Surface starts to crack or dry out → too long, you've lost wetness.
- Steady, slow bubbles → ready to pour.
A bloom that goes much past 60s is fighting you — either you over-bloomed (too much water relative to coffee) or your grind is so coarse the bed is already draining.
Should you stir or swirl?
Three options, increasing in agitation:
- Nothing (just pour and wait). Lowest extraction. Used when you want the cleanest, most acidic cup.
- Swirl (rotate the brewer). Even saturation without disturbing the bed. The most common middle path.
- Stir (push a spoon through the grounds). Highest agitation. Boosts extraction noticeably. Used when the cup tastes under-extracted with the same coffee, ratio, grind, and time.
The stir adds 1–2% extraction yield in a typical V60 brew. That can be the difference between sour and sweet, or balanced and over-extracted, depending on where you started.
When the bloom isn't working
If the bed sits dry — visible patches, no bubbles — you didn't pour enough water, or your kettle stream missed parts of the bed. Either way, the brew is already compromised.
If the bed pulses bubbles but the water has already drained through (you can see the bottom of the brewer), your grind is too coarse for a meaningful bloom. Tighten the grind or reduce bloom water.