Occurrence of the ribes odorant 3‐sulfanyl‐3‐methylbutyl formate in aged beers

2‐Sulfanyl‐3‐methylbutyl formate and acetate were synthesized without purification steps, quantified with a pulsed flame photometric equimolar detector, and characterized by comparison with commercially available 3‐sulfanyl‐3‐methylbutyl formate and acetate (retention indexes, mass spectra, odour descriptors, and intensities). Both formates exhibited a typical ribes flavour, in contrast to both acetates, which were much more piquant. The sensorial threshold of 3‐sulfanyl‐3‐methylbutyl formate was much lower (57 ng/l in beer, BE‐GC‐LoADS = 0.0006 ng) than those measured for the three other esters. Only 3‐sulfanyl‐3‐methylbutyl formate was perceived at the sniffing port in beer extracts. Concentrations up to 1230 ng/l were measured in pilot beers after 1 month at 20°C, although the compounds are rarely detected in commercial beers with highly oxygen‐protected bottling. Accelerated ageing in the presence of oxygen confirmed the key role of oxygen. Copyright © 2013 John Wiley & Sons, Ltd.