I had purchased these coals to use with a Bakhoor burner. I used a electric grill to heat the coals and within a few minutes I saw the bottom red. It took about 8 - 10 minutes for it to heat all the way through. Typically with my circular coals they would produce a lot of smoke and burn through fast. These cubes burned slow and I had minor smoke. When I placed Oud pieces on it the aroma was well produced. Glad I came across these.