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Cold brew concentrate for a party

Concentrate suits a holiday crowd because nothing sits on a warmer and guests mix their own glass. Enter your guest count, the glasses each person drinks and how strong you mix it. You get fl oz of concentrate, bottles to buy or fill, and the grounds if you brew it yourself. For hot coffee, see how much coffee for a party.

Plan your concentrate

Concentrate to have ready
320 fl oz

That is 10 bottles of 32 fl oz for 80 glasses of 8 fl oz. Each glass is one part concentrate to 1 part water or milk, so you also need about 320 fl oz of water or milk.

Brewing it yourself at 1:4: 4732 g (10.43 lb) of coarse grounds steeped in 18927 ml of water.

Examples at 2 glasses each

Four guest counts with 8 fl oz glasses, a 1:4 concentrate and one part water for each part of concentrate. Click a guest count to load it into the form.

Concentrate, bottles and coffee by guest count
Guests Concentrate Coffee to brew it
10 guests 80 fl oz
3 bottles
1183 g
2.61 lb
20 guests 160 fl oz
5 bottles
2366 g
5.22 lb
40 guests 320 fl oz
10 bottles
4732 g
10.43 lb
75 guests 600 fl oz
19 bottles
8872 g
19.56 lb

Stronger and weaker mixes for 20 guests

The same 20 guests with 2 glasses of 8 fl oz each, changing the concentrate and the dilution. A stronger concentrate or a weaker mix means fewer bottles. Glass strength is grams of coffee to grams of all the water used, including the water the grounds held back. A 1:4 brew mixed 1:1 comes out at 1:6. It is the same figure as in the dilution table.

Concentrate and coffee for 20 guests by brew ratio and dilution
Brewed, then mixed Concentrate Coffee Glass strength
1:4 brew, 1:1 water 160 fl oz
5 bottles
2366 g 1:6
1:4 brew, 1:2 water 107 fl oz
4 bottles
1577 g 1:8
1:5 brew, 1:1 water 160 fl oz
5 bottles
1577 g 1:8
1:5 brew, 1:2 water 107 fl oz
4 bottles
1052 g 1:11

Where the numbers come from

One published serving to compare with: Industry Beans suggests a 1:4 ratio of concentrate to water and gives 30 ml of concentrate with 120 ml of water for a classic cold brew. That is a weaker mix than the default here, which is one part water for each part of concentrate. Set the water field to 4 to match it. On the glass strength scale used above, that mix reads about 1:12 if you brew the concentrate at 1:4 (4 + 4 x 2 = 12). The same page uses 30 ml of concentrate per cocktail, about 1 fl oz, which helps if you also serve espresso martinis.

The rest is my own assumptions, so change the inputs if your party differs.

  • Two 8 fl oz glasses per guest. Cold drinks go down fast and people come back for a second. Use 1 for a short event and 3 for an all-afternoon one.
  • The glass size is the drink without ice. Ice takes room in the glass but adds almost no liquid until it melts, so buy it separately.
  • Grounds keep twice their weight in water. That is why a 1:4 brew gives back half its water as concentrate. The gallon page uses the same assumption. Your yield varies with the grind and how hard you squeeze the filter.
  • Bottles hold 32 fl oz, the size of a quart jar. Round up, because the last bottle is the one that runs out at the end of the night.

Making it ahead

A concentrate brewed at 1:4 needs a coarse grind and a long steep. For a party it is easiest to make it in two or three jars the day before, strain them and combine. The grams above are the total, so divide them by the number of jars. The cold brew page has the steep time and grind.

Set out the concentrate with a jug of water, a jug of milk and a bucket of ice, and let guests pour to taste. If most guests will add milk, set the water field to 2 or 3 so the base stays strong. A small second batch from decaf grounds covers the guests who want it.

Unsure how many guests drink coffee at all? The party planner uses event planning shares of 40 to 60 percent, which you can use for the guest field here.

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