I think that would be a good binder, not sure if the pine smell would go away. I would not want everything to have a pine taste.

I don't really care about the finish, as long as its black and heats up the air.  

 If you're concerned about taste/smell, all of my suggestions are terrible. 😅 

 Lol. I love pine smell, just don't think apples would pair with it. This would need tested first 

 Just rubbing charcoal over the surface would darken it enough to make a significant difference in temperature.