Adding Cold-Brewed Coffee to Your Beer

Ever try adding coffee to your boil or brewing some up then adding it before bottling or kegging your beer? Did you get a difficult-to-predict level of bitterness and acid bite? That’s because it was hot! If, instead, you want the taste and aroma of a delicious coffee (and the caffeine, too) in your beer without as much bitterness and bite, you can try to cold-brew it instead.

There are really two ways to cold-brew coffee for your beer. The first is to brew it in your fermentor. To do this, you’ll need to wait until primary fermentation has completed (to be safe, wait a couple days after all the bubbling has quieted down).

Then, you can add coarsely ground coffee beans directly to your secondary in a muslin bag. Be sure to sanitize the coffee (you can do this with some cheap vodka, but ditch the liquid before putting the beans into the secondary). The longer you leave it in secondary, the more likely you are to get astringent flavors and smells from the coffee, so it’s probably best to leave it in for one to three days.

Want to avoid the secondary and increased potential for astringent flavors? Cold-brew it and add it before bottling or kegging. To cold-brew coffee, you probably have everything you could need as a brewer. You’ll need a sanitized vessel that can hold 40+ oz (5 cups), sanitized water, sanitized beans, something (sanitized) to grind the beans with, and something to strain the beans out of the liquid with (e.g. a muslin bag).

The process is very simple (remember to sanitize):

1. Coarsely grind 8 oz of coffee beans. Put the coffee beans in a muslin bag. Put the bag of ground coffee in the vessel you’ve selected.
2. Add about 4 times as much water to the vessel as coffee beans, which translates to 4 cups in this case.
3. Cover your vessel with foil or plastic wrap, then throw it in the fridge for 12+ hours.
4. Pull the muslin bag of coffee grounds out. Let them drip for 15-30 minutes to get all the liquid out (a sanitized strainer would come in handy here). You might also want to extract as much of the flavor as possible by dipping it in one or two more times and letting it drip again.

Now, you have a nicely concentrated amount of cold-brewed coffee. All you have to do now is add this along with your priming sugar before bottling/kegging. This also has the added benefit that you can bottle some without the coffee, then add it for a specific portion of the beer. Two beers in one!

How much should you use for a 5 gallon batch? Consider starting small. Try half of the above recipe (about 2 cups) in the entire 5 gallon batch. Then, add 1 more cup to the second half (this is what it would taste like if you used all 4 cups of coffee in the entire batch). Drink the fourth cup of cold-brewed coffee.

One more added benefit to cold-brewing the coffee and adding it before bottling/kegging is that you see if you’re doing it right without destroying a batch of beer. Just do all of the steps mentioned except adding the coffee to the beer and taste the coffee to see if it’s any good. If it is, it should be good to put in the beer. You can also try adding a small amount to a beer you know is good to see if the flavors blend well (try adding 1.2 tbsp of the concentrate to a 12 oz bottle of porter or stout to get a roughly equivalent taste).

If you’re really concerned about sanitation or are too lazy to sanitize each piece of the cold-brewing equipment and ingredients, I suspect you can boil the cold-brewed coffee along with (or in a separate pot from) your priming sugar. This will likely change the taste profile somewhat, perhaps giving it a caramelized/roasted flavor but still less astringent than a hot-brewed coffee. Never tried it. Have you? Tell me of your experiment! I’ll give this a try soon to see how it turns out.

In summary, coffee doesn’t just have to be added to the boil. You can also cold-brew the coffee either in a fermentor or by itself, then add it before bottling/kegging. As with everything experimental, experiment!