Selecting and PreparingYour Fruits
A hundred years ago, there were many more varieties of fruits grown than today. Commerce has favored the select few that suit the distribution system, and these are not necessarily the ones with the best flavors. If you have the land, the time, and the inclination, many heirloom varieties are available. There is even a society called the North American Fruit Explorers that encourages this sort of historic preservation. Go to nafex.com to see what they’re all about.
Most of us have to be content with the common cultivars. Blending different varieties together can deepen flavors. Mixing sour cherries with black sweet ones, for example, provides a blend of color, depth and acidity resulting in a much better beer. Black and red raspberries can be mixed with synergistic results. One could even add an altogether different fruit—blackberries added to cherries, for example—to a similar end.
Fresh juice may be used, although simply pressing out the juice loses a great deal of flavor and tannin in the skin. Macerating whole or puréed fruit for a few weeks in the secondary will extract some of this skin character. Sometimes a combination of whole fruit and juice can be used.
Cherry pits provide a layer of complex almondy aromatics that really adds to a beer. Raspberry seeds will also add flavor, although they may be a little bitter. Limiting maceration to two weeks for raspberries will keep the pitty bitterness low.
I prefer to work with frozen fruit, as the cellular structure has been disrupted, allowing the flavors and sugars to work their way into the beer quicker than with fresh fruit. I believe freezing lightens the microbial load a bit, although it is by no means a pasteurizing process.
The secondary is the best time to add fruit, as the beer is less vulnerable to spoilage at this point, and the level of out-gassing is lower than in the primary, which means less scrubbing away of aromatics.
Fruit will add a little fermentable sugar to the brew. Cherry juice is between 12 and 22 degrees Brix (which is a percentage measurement like degrees Plato). Raspberries offer just a fraction of that. So the amount of fermentables contributed by fruit to beer is relatively low.
The Beer Basis
Don’t forget the beer underneath it all. You want a brew with flavors and aromas that will harmonize with the fruit, as well as stand up to the strong flavors that may come with it. As always, the highest quality malt should be used. Medium-colored malts from Munich to dark crystal seem to go best with fruits, but dark beers such as stouts and porters are also possible. For these, I would recommend German Carafa malt, as it is processed for a soft, smooth taste.
Hopping is usually present only for balance, as high hop levels often interfere with fruit flavor. By all means, break this rule if you think you have reason to do so. Spices may be used to deepen flavors—cassia or cinnamon added to bring out the cinnamon-like aroma of Montmorency sour cherries, for example.
There is no preferred way to go with yeast. Ale or lager yeast can be used with equal success. At the end of primary fermentation, you can add “wild” Belgian lambic or sour brown cultures which will slowly but surely add their magic to the brew.
These beers will take time. A couple of years for aging is not unusual—again, think wine. Be aware that some of these fruit sugars tend to ferment very slowly, so delay bottling for several months to avoid over carbonation. I assure you, it will be worth the wait.