Good catch, @akitchen 
I hate dealing with blocks and stack/heap issues, so it might be easier to make this a method that just takes klazz of recognizer it looks for and have it do the enumeration inside the method. E.g., 
-(void)pinch {
  [self recognizeAllGesturesMatching:[UIPinchGestureRecognizer class]];
}
-(void)recognizeAllGesturesMatching:(Class)klazz {
  for (UIGestureRecognizer *recognizer in self.gestureRecognizers) {
    if([recognizer class] == klazz) {
      [recognizer recognize];
    }
  }
}