COFFEE · 6 MIN READ

Why Your Pour-Over Coffee Tastes Sour (and How to Fix It)

Sour, sharp, almost lemony coffee is one of the most common pour-over complaints, and it's almost never the beans' fault — it's a sign of under-extraction, meaning water passed through the grounds without pulling out enough of the compounds that balance out acidity. There are really only three variables that cause this, and checking them in order will usually find the culprit fast.

Check your grind size first

This is the most common cause by far. If your grind is too coarse, water flows through too quickly to extract fully — you get the bright, acidic compounds (which dissolve fastest) without the sweeter, heavier ones that develop later in the extraction. The fix is straightforward: grind noticeably finer and brew again. You're looking for a total brew time in the 2:30–3:30 minute range for a standard pour-over; if your coffee is draining in under 2 minutes, your grind is very likely too coarse.

Check your water temperature second

Water that's too cool extracts slower and less completely, which produces the same sour result as a too-coarse grind — this is why it's easy to misdiagnose one as the other. Ideal pour-over temperature is 195–205°F (90–96°C). If you're pouring straight off a rolling boil onto grounds, that's usually fine and actually on the higher, more-extractive end of that range. If you've let the kettle sit and cool for a minute before pouring, you may have drifted below the range without realizing it.

Check your ratio third

Too little coffee relative to water — a ratio like 1:18 or thinner — under-extracts in a different way: there's simply not enough coffee mass for the water to pull enough flavor compounds from, regardless of grind or temperature. A standard starting ratio is 1:15 to 1:16 (1 gram of coffee to 15–16 grams of water). If you've been eyeballing scoops instead of weighing, this is worth checking with an actual kitchen scale before troubleshooting anything else.

The fastest way to isolate which one it is Change only one variable at a time between brews. If you adjust grind, temperature, and ratio all at once and the coffee tastes better, you won't know which change actually fixed it — and you'll be back to guessing next time it happens.

What it means if adjusting all three still doesn't help

If you've dialed in grind, temperature, and ratio and the coffee is still sour, the more likely explanation shifts to the beans themselves — specifically, a very light roast. Lighter roasts are genuinely more acidic by nature (less roasting time means more of the bean's original organic acids survive), and no amount of brewing adjustment fully compensates for that if you personally find it too sharp. At that point, the fix isn't technique — it's trying a slightly darker roast of the same origin.