C-40 will ferment almost completely out, given time. I *have* had luck with very dark homemade candi syrup adding unfermentable sweetness to a couple of sours (this is also how Faro is made, though that's normally blended and served immediately) but you probably don't want to go that route with a kriek.
"I can't believe how many people think Air Lock is pronounced Hydrometer." -BigKahuna
"If you gave me a beer with placenta in it without telling me I would kick you in the nuts." -ODaniel
"We be in a big hurry for dope beer with much alcamahol and flavor, quality, balance, and aroma don't matter. We just wantz to be druck, u know?" -Yooper