How much coffee for a coffee urn
Urns count in small cups. The Hamilton Beach 45-cup urn manual fills 6.4 liters for 45 cups, about 142 ml (4.8 oz) per cup, and calls for 225 g (2 1/4 cups) of ground coffee. That is close to 1:28 by weight, a lot weaker on paper than the 1:16 of a drip machine. A percolator urn cycles the water through the grounds many times, which is why the manual can call for less coffee per cup.
Coffee by urn size
Each cell shows grams, pounds and measuring cups of grounds. The 1:28 column is within a few grams of the manual (228 g against 225 g for 45 cups).
| Urn | Water | 1:28 (manual) | 1:22 | 1:18 (strong) |
|---|---|---|---|---|
| 30 cups | 4.3 L | 152 g 0.34 lb 1.5 cups | 194 g 0.43 lb 1.9 cups | 237 g 0.52 lb 2.4 cups |
| 40 cups | 5.7 L | 203 g 0.45 lb 2 cups | 258 g 0.57 lb 2.6 cups | 316 g 0.7 lb 3.2 cups |
| 45 cups | 6.4 L | 228 g 0.5 lb 2.3 cups | 291 g 0.64 lb 2.9 cups | 355 g 0.78 lb 3.6 cups |
| 50 cups | 7.1 L | 254 g 0.56 lb 2.5 cups | 323 g 0.71 lb 3.2 cups | 394 g 0.87 lb 3.9 cups |
| 60 cups | 8.5 L | 304 g 0.67 lb 3 cups | 387 g 0.85 lb 3.9 cups | 473 g 1.04 lb 4.7 cups |
| 80 cups | 11.4 L | 406 g 0.89 lb 4.1 cups | 516 g 1.14 lb 5.2 cups | 631 g 1.39 lb 6.3 cups |
| 100 cups | 14.2 L | 507 g 1.12 lb 5.1 cups | 646 g 1.42 lb 6.5 cups | 789 g 1.74 lb 7.9 cups |
Cups of grounds use the manual's own conversion of 100 g per cup. Loosely scooped grounds weigh less, so the gram column is the safer one if you have a scale. An urn "cup" is about 142 ml on this Hamilton Beach model and up to about 175 ml on other brands, so a 40-cup urn from another maker can hold more water than the table assumes.
Which strength to pick
1:28 is what the manufacturer prints. Other charts call for more: the urn chart on Talk About Coffee uses 3 cups of grounds for a 40-cup urn and counts an urn cup as 5 to 6 oz. That is about twice the coffee of the manual, roughly 1:20 to 1:24 depending on cup size.
If you don't know the crowd's taste, 1:22 sits between the two. For a 40-cup urn that is 258 g, about 2.6 cups of grounds. Write down what you used, so next time you can go up or down a step.
How much coffee for a crowd
A common planning rule is 1 to 1.5 urn cups per guest (from the same Talk About Coffee guide). The table plans for the high end, so there is enough for refills, and picks the smallest common urn size that holds it.
| People | Cups to brew | Urn | Coffee at 1:28 | Coffee at 1:22 |
|---|---|---|---|---|
| 20 | 20–30 | 30-cup | 152 g 0.34 lb | 194 g 0.43 lb |
| 30 | 30–45 | 45-cup | 228 g 0.5 lb | 291 g 0.64 lb |
| 50 | 50–75 | 80-cup | 380 g 0.84 lb | 484 g 1.07 lb |
| 75 | 75–113 | 2 × 60-cup | 573 g 1.26 lb | 729 g 1.61 lb |
| 100 | 100–150 | 2 × 80-cup | 761 g 1.68 lb | 968 g 2.13 lb |
| 150 | 150–225 | 3 × 80-cup | 1141 g 2.52 lb | 1452 g 3.2 lb |
| 200 | 200–300 | 3 × 100-cup | 1521 g 3.35 lb | 1936 g 4.27 lb |
Coffee is for the high end of the cups column. With more than one urn, split it evenly between them.
For a smaller group, a drip machine is easier. The coffee per cup table covers 1 to 12 cups.
Tips from the manual
- Use a coarse grind, or coffee ground for percolators. Fine grounds can overflow the basket and end up in the cups.
- Wet the basket before adding the coffee, so fewer small particles sift through.
- Fill at least to the minimum line (15 cups on the 45-cup model) and never past the top line.
- Plan on about one minute per cup of brewing time, so a full 45-cup urn needs about 45 minutes.
- If the coffee will sit warm for a long time, take out the basket and stem once it has finished, so the spent grounds don't make it bitter.
Source: Hamilton Beach 45-cup coffee urn use and care guide (PDF). Other brands have their own charts, so check yours if you still have it.