- Author: Milton E McGiffen
The Biochar Journal (https://www.biochar-journal.org/en) had a fairly detailed article on whether to use weight or volume when measuring biochar:
It is a tricky subject, as in ag we often think in terms of pounds per acre. But with biochar, the weight probably includes water and ash. Both of which have their value -- wetter biochar tends to be less dusty, and ash often includes potassium and other nutrients. But if you are looking for just biochar, anything else adds to the shipping cost.
I would rather get as much information as possible when buying and using biochar. In our experiments we have gone to noting dry weight, wet weight, and density. With that information you can convert between volume and weight.