Slow Pour brew guide
Why is my coffee sour or bitter?
Sour coffee is under-extracted: the water didn’t take enough from the grounds, so grind finer, or brew hotter or longer. Bitter coffee is over-extracted: grind coarser, or brew cooler or shorter. Weak or strong is the ratio: change the amount of coffee.
Sour, sharp or thin
The water didn’t take enough out of the coffee. The bright acids dissolve first and the sweetness comes later, so a short or weak extraction tastes sour and finishes quickly.
- First: grind one step finer
- Then: brew a little hotter, just off the boil
- For a press or immersion: steep 30 seconds to a minute longer
- For espresso: grind finer, or let the shot run a little longer
Bitter or harsh
The water took too much. The heavy, bitter and woody compounds come out last.
- First: grind one step coarser
- Then: brew a little cooler (let the kettle rest a minute)
- Pour more gently: hard pours stir up fine particles
- For a moka pot: take it off the heat sooner and cool the base
- For espresso: grind coarser, or stop the shot sooner
Weak or watery
Strength is mostly the ratio. Use a little more coffee for the same water: going from 15 g to 16 g for 250 g of water makes a clear difference. If it’s weak and sour, grind finer too.
Too strong
Nothing is wrong with the brew: add a little more water next time, or top up the cup with hot water. If it’s strong and bitter, grind coarser too.
Flat, hollow or no sweetness
Often the beans are stale, or the brew was uneven, with some coffee overdone and some underdone. Check the roast date (a few days to a month old is best), grind just before brewing, and make sure every grain gets wet at the start with a good bloom and a swirl.
Dry or astringent
That furry, drying feeling usually means too many fine particles were stirred up, or very hot water on a long brew. Agitate less, pour lower and gentler, grind a step coarser, and rinse the paper filter well.
Drains too slowly or too fast
For drippers, the time is a clue. Too slow: the grind is too fine or the fines have clogged the paper, so grind coarser and pour more gently. Too fast: grind finer, and pour into the middle rather than down the paper.
One change at a time
Change only one thing between brews, and change the grind first. Then you learn what each change does, and when you find a cup you love you know how to make it again.
Questions
Can coffee be sour and bitter at the same time?
Yes. That usually means an uneven brew: some grounds over-extracted and some under. Improve evenness first: a better grinder, a full bloom, a gentle swirl and an even pour.
Does dark roast taste bitter?
Darker roasts are more bitter by nature and extract faster. Brew them a little cooler and coarser.
Is sour coffee the same as acidic coffee?
Not quite. Pleasant acidity is bright and fruity, like a good apple. Sourness is sharp and unpleasant, and it’s a sign of under-extraction.