What is black garlic?
Garlic is fermented anywhere from 15 to 90 days, resulting in the cloves turning black and turning a sticky jelly like texture. The taste is sweet and syrupy with hints of balsamic vinegar. You can use the cloves as you would use roasted garlic,
Because of its delicate and muted flavors, a considerably larger amount of black garlic must be used in comparison to white garlic in order to achieve a similar level of intensity. Additionally, black garlic cannot be used in place of white garlic. If a garlic flavor is desired in addition to the flavor of black garlic, then fresh garlic must be added.
Unlike the vegetable from which it is made, white garlic, black garlic has a very subtle and muted flavor that is easily overpowered.
Partial credit: https://en.wikipedia.org/wiki/Black_garlic