I've spent the last week trying all the coal "brands" I can find around my area. Blaschak, Reading and "Mystery Coal" from one of the local retailers. I burned 100 pounds of each and really just observed the ash and burn temps. I didn't notice any real differences in the burn temps at what appeared to be similar "burns" but there were significant differences in the ash and fly ash produced. The Reading and the "Mystery Coal" (which I think is just Reading) seemed to burn about the same with the same ash and similar fly ash buildup on the glass, etc. Ash was mostly tan in color. The Blaschak was different. First of all it it was slightly larger pieces than the other coal. This may sound weird, but it "sounded" different than the other coal when I scooped it and dumped it in the hopper. It sounded like it was "ceramic" or glass where the other coal sounded more "dead"...does that make any sense at all?
The ash was much more red than the other coal and there was less unburnt coal in the pan. The flyash seemed about the same, easily cleaned off the glass with a wet paper towel. The first coal I had was 150 pounds of this stuff from a dealer in Ovid, NY... a buddy loaned me a few bags to get started. I did not like this coal as compared to the others. Lots more ash (tan), flyash was a pain to get off the glass, etc.
I know this isn't very scientific, but from my observations, I think I'm going to go get 500 pounds of the Blaschak to burn. Seemed to me to be the best of the bunch. I suppose that each bag of even the same bag could have different characteristics depending on how it's blended and where it came from. Correct or not?