2-ACETYL-1-PYRROLINE
FROM SPARKLING · the brioche note from yeast aging
The fresh-bread aroma: basmati rice, pandan leaves, jasmine rice, and the bottom crust of any baked loaf all share it. In wine and beer it appears during yeast autolysis: dead yeast cells slowly release the molecule during long aging on the lees. Champagne's signature brioche note is acetyl pyrroline doing the work; a tank-method sparkling without lees aging doesn't develop it.