Start at 15 : 250
Fifteen grams of coffee, 250 ml of water just off the boil. Bloom for 45 seconds.
Cup one — too fast?
If the draw-down finishes before 2:30 and the cup tastes thin and sour, grind finer.
Cup two — too slow?
Past 3:15 and bitter? Go coarser. By cup three you are there.
