Rick, how do you tell if that valve is closing? I have had trouble swallowing capsules of supplements because it feels like they're jamming up in my esophagus, and not going into my stomach right away. If I don't leave several minutes between each capsule, it's uncomfortable and I wonder if I'm doing any damage. I actually sprinkle everything I can onto food or into drinks to avoid the problem, but some like magnesium citrate are too bitter for that.