Charcoal-fired coffee is actually a synonym for coffee produced under a coffee roasting method in Japan.
Originally refers to the Japanese roasting of coffee, the use of traditional charcoal fire as a heat source, a long period of small fire slow roasting to get a strong sense of bitterness, caramel and tobacco flavor of charcoal roasted coffee beans, this charcoal roasted coffee because of its non-acidic, scorched bitter and mellow feeling and named.

Is there a difference between charcoal-fired coffee and black coffee?
Based on the above description of charcoal-fired coffee, it can be concluded that pure charcoal-fired coffee itself is one of the black coffees.
Charcoal-fired coffee is black coffee, and black coffee is not only a kind of charcoal-fired coffee.
This is a relationship of inclusion and inclusion.
Black coffee contains charcoal-grilled coffee with other additive-free coffees.
The difference between charcoal-fired black coffee and charcoal-fired/carbon-fired three-in-one coffee
Charcoal-fired black coffee refers to charcoal-fired pure coffee without any additions: it can refer to charcoal-fired coffee beans, charcoal-fired coffee bean milling powder, and instant pure coffee powder made of charcoal-fired coffee beans.
Of course, you can add any favorite condiment to your charcoal-grilled black coffee, such as milk, sugar, milk balls, or other beverages.
The so-called charcoal-fired three-in-one coffee on the market is actually the taste of instant coffee, and its raw materials are instant coffee powder + creamer + sugar, and other flavor substances may be added for Titian. So it's not really charcoal-fired coffee at all!
Unless you feel that you should go to a "brain processing factory", don't say that so-and-so's charcoal-fired three-in-one coffee is authentic...