I have a cob that I rotate with my briar. I have been using the dr grabow filters with it, and while the filter does its job, it doesn't take long for it to become soggy with moisture at which point it is similar to trying to draw from a bowl that was packed too tightly. Normally, I replace it when this happens. however, the other day i was caught out and about without an extra filter. So I simpy removed it and smoked filterless. After the bowl was finished I attempted to remove the stem and discovered that it had grown very tight. I assumed the shank had swollen from moisture accumulation so I let the pipe rest for quite some time (about a week) before smoking it again. the condition improved but only slightly. should I be concerned? should I always use a filter for this type of pipe?