The Batch Brewing Formula
Brewing for a crowd is just the golden ratio scaled up. Multiply the number of cups by your cup size to get total water, then divide that water by your ratio to get the coffee. A millilitre of water weighs about a gram, so twelve 240 ml cups make 2880 ml of water, and at 1:16 that needs about 180 g of coffee. This works for any drip machine, airpot, or large French press, and it takes the guesswork out of doubling or tripling a recipe for a meeting, brunch, or event.
Batch Brew Chart (at 1:16)
Coffee and water for common cup counts, using 240 ml cups:
| Cups | Total water | Coffee | Tablespoons |
|---|---|---|---|
| 4 | 960 ml | 60 g | 11 |
| 8 | 1920 ml | 120 g | 23 |
| 12 | 2880 ml | 180 g | 34 |
| 20 | 4800 ml | 300 g | 57 |
| 30 | 7200 ml | 450 g | 85 |
Scaling Up Without Losing Quality
Ratio holds steady as you scale, but a few things change with volume. Very large batches can taste slightly strong, so nudging toward 1:17 is fine for big urns. Use a grind matched to your brewer, keep the water just off the boil for drip and airpots, and serve within thirty to sixty minutes; coffee left on a hot plate scorches and turns bitter, so an insulated airpot beats a warming burner. For events, brew in stages rather than one giant pot so the last cup tastes as good as the first.
Frequently Asked Questions
How much coffee for a pot of coffee? Multiply cups by cup size for total water, then divide by your ratio; 12 cups at 1:16 is about 180 g.
How much coffee per cup? Around 13 to 16 g per 240 ml cup at standard strength.
What ratio for batch brewing? 1:16 is standard; go to 1:17 for very large batches that can taste strong.
How long does brewed coffee stay good? Best within 30 to 60 minutes; hold it in an insulated airpot, not on a burner.