Fruit Beers: How Much Fruit?

I recently decided to brew a cherry dunkelweizen in the near future. Seems like a good springtime beer; some cherry tartness should be a nice complement to the banana- and clove-like yeast esters and likewise balance the sweet malts. I scribbled out a sound base recipe for a dunkelweizen without too much trouble (see below). Now I just have to figure out how much cherry to use. And this is where I hesitate. Brewing with fruit is not something I do often. How much cherry flavor is appropriate in the finished beer? Furthermore, how much fruit is appropriate in a beer in general?

I usually have trouble with qualitative analysis of fruit beers. For example, consider an extremely overstated raspberry beer. One that both smells and tastes like fresh raspberry and nothing else. I like raspberries, so I may enjoy drinking it. But is it well-made? Not really. I can buy some raspberry juice or wine and accomplish the same effect. So while it may be a decent beverage, it is not an impressive beer. Balance is typically the hallmark of a world class brew, and these "fruit-bombs" are anything but balanced. But then the issue becomes the definition of "balanced." I think I've established that the base beer should at least be detectable, but at what proportion of base beer to fruit is the beer balanced? The usual axiom for spiced beers is that if the drinker can identify the spice, then it's too much (the cardamom in Stone Vertical Epic 07.07.07 comes to mind). Fruit beers, though, seem to have a different standard; they require more fruit presence. After all, eating plain blueberries is commonplace, but I don't know anyone that will eat a spoonful of straight coriander (dares aside).

Hanssens Oudbeitje, a nice fruit lambic
made with Strawberries.

Then there are lambics. These traditional spontaneously-fermented beers are usually musty and sour, and frequently include fruit to add a little bit of balance and complexity. Because of the strong flavors involved, lambics can get away with more fruit than other styles without becoming overwhelming. It's still possible to have too much, though. Most products from Brouwerij Lindemans are far over-the-top with fruit. Try a Lindemans Kriek and a Cantillon Kriek (both lambics with cherries) side-by-side and decide which one is better executed.

After all of this, I still haven't answered my initial question. The fruit in a fruit beer should be identifiable, but not overwhelming. There's still a lot of room for play between the extremes. I'll call this the zone of "open to interpretation." As for my cherry dunkelweizen, I think I'll choose the conservative route with the fruit. Present, but toward the background. We'll see how it goes.

Oh, and for the curious, here is the base recipe for the dunkeweizen:

68% wheat malt
25% dark Munich malt
3.5% chocolate wheat
3.5% Special B

~10 IBU worth of Mt. Hood hops for bittering only. Weihenstephaner yeast. Cherry (amount TBD) in secondary.

Cheers,
--Joe