Matching the Fruit to the Coffee
Usually when I’m designing these beers, I already have a coffee in mind, which helps me to lay out the fruit profile. It helps to experience the coffee in different ways to get the full range of the varietal. Obviously, an espresso and a cold brew of the same coffee will have very different characteristics—but this will help you get a better idea of what fruits are possible with each coffee varietal.
It’s always helpful to talk directly to the coffee roaster about the coffee and get their take on the tasting notes.
The coffees that tend to be more berry- and sweet fruit–forward pair naturally with softer fruits, such as blueberry, boysenberry, or even sweeter citrus such as Valencia orange. I find that really vibrant, citrus-forward coffees pair well with more intense fruits—usually raspberry or passion fruit.
The Not-Too-Acidic Base Beer
I like to think of the fruit as the bridge between the sour base and the coffee. If you’re able to use fruits that complement the notes of the coffee, it helps to wrap all the ingredients into a nice, concise package. For softer, sweeter fruits, I generally add about one pound of fruit per gallon of beer (about 120 grams per liter). For more intense, acidic fruits I use about half that.
Using a sour base beer that isn’t overly acidic helps to create more harmony in the product. In some cases, this can require blending in some non-soured beer to get the right balance. If the beer is far too acidic, it complicates the palate and makes for an intense and confusing combination.
Using the Coffee
When I’m using fruits and a coffee that I know are a sure combination—such as Ethiopian coffee and darker berry fruits—I’ll use anywhere from one to two pounds of coffee per barrel of beer (about 2.6 to 5.2 ounces per five gallons, or 74 to 147 grams per 19 liters). My ratio is 50 percent whole beans to 50 percent very coarse ground; I’ll first steep the whole beans in the beer for 36 hours, then I’ll remove the beans and steep the coarse-ground coffee for no more than 32 hours.
I aim for direct bean-to-beer contact to get all of the flavor and aroma necessary for each beer—but there are times that adding cold brew after steeping the coffee is needed for a finishing touch. I always add the cold brew to taste, right before packaging and carbonation. It’s important to try to remove as much oxygen from the cold brew as possible; gently bubbling CO2 into the cold brew for a few minutes before adding it can pay dividends for product stability.
Using whole beans provides so much aroma—think fresh-roasted coffee in a bag—without a terrible amount on the palate. This is a great tool to use when you don’t want to overly complicate the flavor of the beer, but you want to provide a nice coffee aroma with minimal flavor. I generally use mostly whole beans if the combination of fruit and coffee is a little on the cavalier side and I want to give myself room for adjustment.
Using coarse grounds provides a lot of flavor on the palate—touches of earthiness if you go heavy—and a nice, roasted, coffee-ground aroma. Using coarse-ground, it’s really important that you don't over-steep the coffee. My rule of thumb is absolutely no more than 42 hours. Generally, it’s a maximum of 36 hours on whole bean and a maximum of 32 hours on coarse-ground. Leaving the coffee on the beer too long can give you off-flavors ranging from pepper skins, mushroom earthiness, and mint/herbal tea flavors.
When using fruit combinations, I like to use a vibrant fruit and a softer fruit. Obviously, something like passion fruit packs a ton of tartness, so I would pair it with something like mango to provide a complementary sweetness that can help boost the coffee without distracting from the overall beer.