Oak can be a source of a wide variety of sweet elements. Untoasted wood supplies a coconut influence (whiskey lactone), usually subliminal, which lifts out varietal fruit aromas. This compound is rich in French forests where sessile oak species (Quercus petraea or Q. sessiliflora) predominate, such as those of Alliers, Vosges, and Argonne. Alternatively, toasting can enrich vanilla, toffee, and sometimes sweet coffee elements. The flame converts cellulose to cellobiose, an exotic sugar that can feed Brettanomyces.
