Dottle

Dottle is the wet and sour-smelling mass of unburned tobacco found at the bottom of a tobacco pipe. Dottle is produced for a combination of two reasons. One; the smoker is a wet smoker, that is, he pushes a considerable amount of saliva down the stem and into the bowl. Two; the tobacco being smoked is excessively moist. Puffing too fast can also be a factor depending on the humidity of the tobacco. The foul liquid that collects at the bottom of a pipe results in gurgling and can be accidentally sucked up. Pushing a pipe cleaner down the stem can remedy this problem to a point.

Dottles are generally considered troublesome because they lessen the time one may spend smoking a bowl. Dottles can also give a sour taste to the smoke as it is approached by the hot ember. If dottle is not promptly removed after smoking, the pipe may eventually give a foul taste to any tobacco smoked in it. When this happens, pipe sweetening is required.

Some pipes are designed to specifically lessen or prevent the formation of dottle and excessive moisture. The most common are the calabash pipe and the Dry System pipes made by Peterson.

In the Sherlock Holmes stories, Sherlock had a habit of drying out all the dottles from the day's pipes on a corner of his mantlepiece  to be smoked the following morning.