Three or four years ago i found at those places called "Zum Mitnehmen" a bag of particular grill "charcoal".
I put the "..." because they look like small stones and i assumes they are made from something else than wood (perhaps volcanic magma?).
They light up very hard, but they are very efficient from the heating perspective.
However, i dont know the producer and the name of such a product.
Does anyone has any idea about such kind of "charcoal"?
Thank you