About

Extraction yield in coffee brewing is governed by the mass ratio of dry coffee grounds to water. The Specialty Coffee Association (SCA) defines the "Golden Cup" standard as a ratio of 1:16.67 (approximately 55g/L), targeting a Total Dissolved Solids (TDS) between 1.15 - 1.35% and an extraction yield of 18 - 22%. Deviating from optimal ratios produces under-extracted (sour, thin) or over-extracted (bitter, astringent) cups. This calculator applies method-specific ratios accounting for immersion time, grind surface area, and pressure variables. Note: results assume water at 92 - 96°C and a standard atmospheric pressure of 1atm. Altitude, water mineral content (50 - 150ppm TDS recommended), and bean roast level will shift ideal parameters.

Formulas

The fundamental brew ratio expresses the mass relationship between dry coffee grounds and brewing water:

W = C × R

where W = water mass in g, C = coffee mass in g, and R = ratio factor (the "N" in 1:N).

Inversely, to derive coffee from a target water volume:

C = WR

For multiple servings:

W_total = C × R × S

where S = number of servings. Strength adjustment modifies R within a bounded range: R_adj = R_base × (1 + k), where k ∈ [−0.3, +0.3]. Unit conversions: 1oz = 28.3495g, 1tbsp coffee ≈ 5g, 1cup water = 236.588ml.

Reference Data

Brew Method	Ratio (Coffee:Water)	Water Temp	Grind Size	Brew Time	Yield per Cup
Pour-Over (V60/Chemex)	1:16	93 - 96°C	Medium-Fine	3 - 4min	237ml
French Press	1:15	93 - 96°C	Coarse	4min	237ml
AeroPress	1:12	85 - 92°C	Fine-Medium	1 - 2min	200ml
Espresso	1:2	90 - 96°C	Very Fine	25 - 30s	36ml
Cold Brew	1:8	Room/4°C	Extra Coarse	12 - 24hr	237ml
Moka Pot	1:7	100°C (boiling)	Fine	4 - 5min	60ml
Drip Machine	1:17	92 - 96°C	Medium	5 - 6min	237ml
Turkish/Ibrik	1:10	100°C	Extra Fine (powder)	2 - 3min	90ml
Siphon/Vacuum	1:15	92 - 94°C	Medium	3 - 5min	237ml
Percolator	1:17	92 - 96°C	Coarse	7 - 10min	237ml
Clever Dripper	1:15	92 - 95°C	Medium-Coarse	3 - 4min	237ml
Kalita Wave	1:16	92 - 96°C	Medium	3 - 4min	237ml
Nel Drip	1:14	88 - 92°C	Medium-Coarse	3 - 5min	200ml
Vietnamese Phin	1:6	96°C	Medium-Coarse	5 - 7min	120ml
Lungo	1:3	90 - 96°C	Fine	45 - 60s	60ml

Frequently Asked Questions

Higher water temperature increases the rate of soluble extraction. At 96°C, more bitter compounds (chlorogenic acid lactones, phenylindanes) dissolve faster, while at 85°C, extraction favors fruity acids. If you brew with water below 90°C, consider decreasing your ratio by 1-2 points (e.g., 1:16 → 1:14) to compensate for reduced solvency. Cold brew uses a drastically lower ratio (1:8) precisely because the 12-24 hour steep time at low temperature replaces thermal energy with contact time.

The SCA Golden Cup standard (1:16.67) targets drip/pour-over methods where gravity drives water through a bed of medium-ground coffee at atmospheric pressure. Espresso operates at 9 bars of pressure forcing water through a compact puck of finely-ground coffee in 25-30 seconds. The extreme pressure and fine grind extract soluble compounds far more efficiently per unit of water, so a 1:2 ratio (e.g., 18g coffee → 36g liquid) achieves a TDS of 8-12%, compared to drip's 1.15-1.35%. These are fundamentally different extraction regimes.

Grind size does not change the mass ratio but dramatically affects extraction yield at that ratio. Finer grinds expose more surface area, increasing extraction. Using a pour-over ratio of 1:16 with an espresso-fine grind will over-extract, producing bitterness. Conversely, coarse grinds with the same ratio under-extract. Each method's recommended grind size is calibrated to its ratio and contact time. The calculator assumes you are using the grind size appropriate for the selected brew method.

Dark roasts are more porous and soluble due to extended Maillard reactions and caramelization. They extract faster and yield more dissolved solids at the same ratio. Reduce the ratio by 1-2 points for dark roasts (e.g., 1:16 → 1:17 or 1:18) to avoid over-extraction. Light roasts are denser and less soluble - increase the ratio by 1-2 points (1:16 → 1:15 or 1:14) or raise water temperature to 96°C. Use the strength slider in this calculator to make these adjustments.

The SCA recommends brewing water with 50-150 ppm total dissolved solids, ideally around 150 ppm with a calcium hardness of 50-175 ppm CaCO₃. Distilled water (0 ppm) under-extracts because mineral ions (particularly magnesium and calcium) act as extraction catalysts bonding to flavor compounds. Hard water (>250 ppm) over-extracts and adds metallic or chalky tastes. The brew ratio calculator assumes water within the SCA-recommended mineral range. Adjusting mineral content can shift your effective extraction by ±2% yield.

Ratios scale linearly for mass. If 1:16 means 15g coffee to 240g water, then 150g coffee to 2400g water is mathematically correct. However, large batch brewing introduces variables: uneven water distribution over a large coffee bed, heat loss during extended brew times, and channeling. For batches above 1 liter in pour-over, consider increasing the ratio by 0.5-1 point (1:16 → 1:16.5) and using a coarser grind to maintain even flow. The servings multiplier in this calculator handles the linear scaling.