It does not matter how slow I am going to smoke that, at the end of it, I always a dottle at the bottom of my bowl, which I hate. I have noticed, though, that some mixtures, if properly dried, leave much less residue than others. Say for example Nightcap or Durbar. On the other hand, some VaPers, such as the Elisabethan Mixture, which I love, will leave more dottle even if properly dried. I usually leave my tobacco tin open for 24 hours before smoking, and depending what mixture, it could be more, but I can never get rid of the insidious dottle at the bottom of my bowl.