5 things that help with a V60 pour-over that drains too fast and comes out thin and sour

When a V60 drains fast, every instinct says grind finer. But most grinders below about £300 produce a significant fines fraction, and going finer increases that fraction exponentially. Those fines clump, clog unevenly, then release all at once — a fast drain in patches while the rest of the bed barely sees water. The sour-thin combination is textbook under-extraction, but not from coarseness; it's from channelling. A coarser grind that produces a steady laminar flow extracts more evenly than a fine grind with a chaotic, lurching drawdown. To compensate for the reduced surface area, add 1–1.5 g to your dose.

The standard advice to rinse the paper is really about pre-heating the brewer — but almost nobody actually waits long enough. A cold ceramic or glass V60 sitting on a cool worktop will pull 5–8°C out of your brew water the moment it makes contact. That lost heat collapses extraction before the grounds have had any time with the water: acids come out fast at low temperatures, the heavier compounds that give coffee body and sweetness barely dissolve. The thin sourness you're tasting is partly the cup telling you the brewer was cold. This is worst in winter or if your dripper lives on a stone countertop.

The bloom stage is where channelling is born, and most people skip the one step that actually prevents it. Dry clumps of coffee survive the bloom pour and sit like tiny breakwaters, letting water rush around them rather than through them during every subsequent pour. A quick stir with a chopstick immediately after bloom water goes in — not violent, just enough to wet every particle — breaks those clumps apart before extraction begins. This is especially important with very fresh coffee, where CO2 is actively pushing water away from dry patches, but it matters even with coffee a week or two off roast.

Holding the kettle 20–25 cm above the slurry creates a jet that punches through the coffee bed, bores a channel down the centre, and gives water a low-resistance path straight to the drain. The same pour speed from 5–8 cm above the surface disperses energy across the slurry instead of driving it into a single point. Lower height means less turbulence, the bed stays packed and even, and water has to move through coffee rather than past it. Pouring more slowly at height helps a little; pouring low helps a lot more.

Sour and thin together almost always mean the sweeter, heavier compounds never dissolved — and those compounds require heat. Many of the molecules responsible for sweetness and body only become soluble above 93°C. If you're brewing a light or medium-light roast at 90–92°C (common if you let the kettle sit for a minute after boiling), you're leaving most of what makes that coffee good sitting in the grounds. Increasing temperature is the highest-leverage single variable for under-extracted light roasts, and it costs nothing to try first.