Recently tried out a Java Log, a firelog made from compressed coffee grinds.

Pros:

Excellent survival heat source.

Burns hot for a full 2+ hours.

Quiet. No crackling.

Doesn't pop out embers like burning wood.

Very little ash.



Cons:

Expensive at $6-7 each.



I imagine you could make these yourself. The problem would be compressing the grinds enough to get keep the form and have a long burn time.