Today I burnt a hotter and larger fire than normal in my masonry heater (Temp-Cast 2000). When I went outside I was surprised to find the smoke from the chimney was very black and smelled like coal. Normally the smoke fom the heater is very minimal. I had some creosote build up from burning a load of wet wood earlier in the season and the only thing i could figure was the smoke was from some of the creosote burning. Otherwise everything seemed fine and I don't think i had a chimney fire. Any one have any other ideas?