Odorant Polyfunctional Thiols Issued from Bottle Beer Refermentation

Bottle refermentation, which imparts beer effervescence and resistance against infection and oxidation, is also known to improve flavor profile and stability. Some stale off-flavors exhaled by aldehydes are known to be reduced into alcohols. Yeast esterases can also affect beers’ fruity character by hydrolyzing esters. In this work, the polyfunctional thiol contents of beers submitted or not submitted to bottle refermentation were compared. A specific pHMB thiol extraction was applied and the extracts analyzed by GC-MS, GC-PFPD, and GC-olfactometry (AEDA). A large number of sulfanylalkylalcohols, sulfanylalkylacetates, and sulfanylalkylcarbonyles were produced during bottle refermentation.