How sotolon can impart a Madeira off-flavor to aged beers.
4,5-Dimethyl-3-hydroxy-2(5H)-furanone or sotolon is known to impart powerful Madeira-oxidized-curry-walnut notes to various alcoholic beverages. It has been much studied in oxidized Jura flor-sherry wines, aged Roussillon sweet wines, and old Port wines, in which it contributes to the characteristic "Madeira-oxidized" aroma of these beverages. No scientific paper describes how sotolon might be involved in the Madeira off-flavor found in aged beers. The specific extraction procedure applied here allowed us to quantify this lactone in 7 special beers, at levels sometimes well above its threshold (from 5 to 42 μg/L after 6, 12, 18, and 24 months of natural aging, while unquantifiable in fresh beer). Investigation of spiked beers led us to highlight the key role of pro-oxidants and acetaldehyde. Addition of ascorbic acid without sulfites should be avoided by brewers, as the former would intensify sotolon synthesis. Acetoin, a beer fermentation byproduct, also emerged as possible precursor in beer when combined with serine.
Unité de Brasserie et des Industries Alimentaires, Earth and Life Institute ELIM, Faculté d'Ingénierie biologique, agronomique et environnementale, Université catholique de Louvain, Croix du Sud, 2 box L7.05.07, B-1348 Louvain-la-Neuve, Belgium.
Caroline
C
Scholtes
Unité de Brasserie et des Industries Alimentaires, Earth and Life Institute ELIM, Faculté d'Ingénierie biologique, agronomique et environnementale, Université catholique de Louvain, Croix du Sud, 2 box L7.05.07, B-1348 Louvain-la-Neuve, Belgium.
Sabrina
S
Nizet
Unité de Brasserie et des Industries Alimentaires, Earth and Life Institute ELIM, Faculté d'Ingénierie biologique, agronomique et environnementale, Université catholique de Louvain, Croix du Sud, 2 box L7.05.07, B-1348 Louvain-la-Neuve, Belgium.
Sonia
S
Collin
D000093:Acetoin / Q000737:chemistry; D001515:Beer / Q000032:analysis*; D005285:Fermentation; D005421:Flavoring Agents / Q000737:chemistry*; D005663:Furans / Q000737:chemistry*; D006801:Humans; D009812:Odorants / Q000032:analysis; D010084:Oxidation-Reduction; D013649:Taste
D005421:Flavoring Agents; D005663:Furans; C054511:4,5-dimethyl-3-hydroxy-2(5H)-furanone; D000093:Acetoin
aging; beer aroma; oxidation; sotolon