My guess is that it was stacked where it was rained upon. This happens to me, with my own firewood, when I use stuff which I haven't had tarped. As long as it isn't rotten, it should straighten out okay. Tarp your firewood. Also, if you can do it, stack a fair amount near where you will burn it (inside). If it is stacked near your fireplace, it will dry out faster yet.

If I'm correct, your wood will begin to burn more normally within a week.

George
Tahlequah, OK

We use old wood all the time and it isn't a problem. Some woods just burn hotter than others and have different qualities...some harder and some softer. People who use wood cook stoves, often select the wood to use for how how or prolonged they want their fires. I don't know a lot about it just voicing a few thoughts.

I think both of your comments are accurate. I think the wood was stored uncovered, but now that it's drying out, it's burning a lot better.