People from all over the world subscribe to the biochar Google Group, biochar.groups.io. Knowledge and experience and education vary widely therein, as in most online groups, but many of the best minds on the subject tend to drop a line or two. Among such company, I find it most useful to just sit back and read. But once in awhile, something gets said that stimulates me to respond.
More than once, someone on this list has stated that biochar is not charcoal. I am a copy editor as well as a biochar maker and instructor. Definitions are very important in both realms, and I knew that these folks were not distinguishing biochar and charcoal correctly.
In eighth grade we learned about subsets. All members of subsets are members of the superset, but not so in the reverse. For example, every square is a rectangle.
Likewise, all biochar is charcoal. Charcoal is defined as the solid product of biomass pyrolysis. Not all charcoal qualifies as biochar, but all biochar qualifies as charcoal.
Take the charcoal that you buy in bags for your barbecue, for example. No one cares about expelling soot and tar from barbecue charcoal; they are what impart the characteristic barbecue flavor to the stuff on your grill. That’s why the wood from which it is made is printed on the package. If we were to pyrolyze the same wood for biochar, a high percentage of the impurities would be removed, and our food might not taste as good. Differences in process temperature and residence time are what create the different results, not to mention the species composition and tolerance for moisture.
There is definitely a distinction that needs to be made, but it is not between biochar and charcoal. The difference is between what can properly be called biochar and every other kind of charcoal. Biochar cannot be said to be other than charcoal, but many solid residues of pyrolysis can be said to not be biochar.
I finally went ahead and said all this to the group. I predict that the matter will not go away, because for many of them, there is biochar to be sold, and in marketing, distinctions are more important than facts.