- Spring 1996 "Update" Newsletter Article -
Report focuses on hydrogen sulfide in wine
From CATI Publication #960401
Copyright © 1996. All rights reserved.
A pair of scientists at California State University, Fresno's Viticulture and Enology Research Center (VERC) has taken a new approach to solving an old, yet persistent problem in the white wine industry-the formation of hydrogen sulfide.
In spite of new and improved winemaking practices, "the problem [of hydrogen sulfide] has defied solution," stated enology professor Carlos Muller in explaining reasons for addressing the issue. Hydrogen sulfide's characteristic odor, reminiscent of rotten eggs, can be detected at levels as low as 20 parts per billion (ppb) in white wines, and can be the cause of a quick rejection by consumers, he noted.
In a new approach focusing on the acidic properties of white wine, Muller, along with winemaker and associate professor Ken Fugelsang, is studying a chemical compound that is not normally seen as a precursor of H2S.
"White wine is also acidic; this provides ideal catalytic conditions for the interaction of acetaldehyde and hydrogen sulfide for the formation of 2,4,6-trimethyl-1,3,5-trithiane, a cyclic thioacetal that has been postulated by us as a source (perhaps the primary source) of post-bottling hydrogen sulfide."
The researchers have conducted trials recreating the conditions they believe result in formation of H2S. And sensory examinations have indicated their hypothesis is correct.
The pair will present details of their work at seminars later this year. Specifics of the project also are available in a new research publication produced by CATI. It is entitled "Post-Bottling Hydrogen Sulfide: 2,4,6-Trimethyl-1,3,5-Trithiane As a Source." To obtain a copy, see the publications order form on Page 7.{ page top }