Advanced options
Ratios are by weight: 1:16 means 1g coffee to 16g (=16ml) water. Scales beat scoops because beans vary in density, but a level tablespoon of ground coffee is ~7g when improvising. Adjust strength with the ratio, adjust bitterness/sourness with the grind: finer and longer extracts more.
What The Coffee Ratio Calculator Works Out
- Coffee: water divided by the ratio, so two 250ml cups at 1:16 is 500ml of water and about 31g of coffee. Brewing by weight replaces the heaped-scoop lottery with repeatability; a level tablespoon of ground coffee is about 7g when improvising, but beans lie: a scoop of dense light roast holds more coffee than a scoop of puffed dark.
- Water: cups x 250ml, just off the boil at 92C to 96C. The speciality consensus band runs 1:15 (strong) to 1:18 (mild), with 1:16 the crowd-pleasing centre.
- Grind and time: ratio sets strength; extraction sets flavour. Grind size and contact time govern how much dissolves: under-extraction reads sour and thin, over-extraction bitter and hollow, so adjust grind before ratio, finer for sour and coarser for bitter. Cafetiere coarse-and-four-minutes, pour over medium-and-three, cold brew coarsest-and-overnight.
- Cup size and custom ratio (advanced): a 350ml mug or a 150ml cup changes the dose in proportion, and any ratio from 1:10 (cold brew concentrate) to 1:20 can be entered directly.
- Brew from your dose (advanced): work backwards from the grams of coffee left in the bag to the water that matches your ratio.
- Cost per cup and bags a month (advanced): grams per cup x the bag price per gram. A GBP 6 bag of 250g makes about 16 cups at 1:16, roughly 38p each, and two cups a day gets through about four bags a month.
- Yearly coffee spend (advanced): the home figure against the same cups at a cafe price (GBP 3.40 is a typical 2026 flat white), which is the quiet reason the ratio habit funds its own equipment drift and still saves money.
- Bloom water (advanced): for pour over, twice the coffee's weight in water poured first and left 30 seconds to de-gas is the one ritual with a measurable payoff. Freshness, filtered water and a burr grinder come before any further hardware.