Few ingredients rouse greater passion than the addition of fruit to a beer. Many people are strongly opposed to fruit in their ales and lagers. Heck, the Germans enacted the Reinheitsgebot literally outlawing the addition of "foreign" ingredients, such as fruit, in their beer. Many guys won't even touch a beer if there is any indication of added fruit, as if drinking "fruited" beer is equivalent to drinking a Zima. Beer brewed with fruit additions at either the end of the boil or during secondary fermentation can add take a beer and add another layer of complexity. I think a critical point of a decent fruit beer is that it should be a beer with fruit, not the other way around. Meaning if it just tastes like alcoholic fruit juice then it ain't worth brewing or buying, but if the fruit enhances or adds another aspect (e.g. added acidity or sourness) to the beer then it can be a welcomed addition.
To experiment, I recently brewed a Belgian Brown ale and split it, one half of the batch remained untouched and the other half was racked onto several pounds of sour cherries for a month. The result was definitely interesting, the two beers didn't taste like they were brewed in the same kettle. The untouched brown (or brune or bruin) was more viscous, malty, and sweet with some moderate hop bitterness on the back end. The "cherried" version was tart, with a thinner body (and not surprisingly a lower final gravity), and ended with a blend of hop/fruit bitterness. To be quite honest I enjoy the regular brown more, but I think this was a cool experiment. Next time I think I will blend in some sweet cherries.
Several years ago I brewed a west coast style pale ale and added grapefruit to the secondary fermentation. The fruit really enhanced the natural citrusy taste of the cascade and centennial hops that I used. Thinking back to that beer makes me wonder, why I haven't tried this combination again, perhaps a future brew.
A commercial beer brewed with fruit that I think is worth a try is Dogfish Head's Aprihop.
-HolzBrew
