Retrieve dry wood ashes from a source of combustion and pass them through a sieve, leaving only the powder.
Part a: Mix 50ml of Water with 15g of sugar to dilute the sugar
Part b: Mix 100ml of water with 10g of agar agar.
Part c: Mix 100ml of water with 60g of wood ashes and 3g of calcium propionate.
Once each mixture is hydrated mix parts a and b together in a pot on the stove. When it starts to boil, then incorporate part c (the biochar/ashes mixture) and wait until it boils again. Put in moulds and wait to dry.