Issue link: https://read.dmtmag.com/i/590181
7 0 V I N E YA R D & W I N E RY M A N A G E M E N T | N o v - D e c 2 015 w w w. v w m m e d i a . c o m + Volatile sulfur compounds produce a range of off- odors, but also can add interesting complexity to wine. + Most winemakers try to avoid reduction, because its effects are mainly negative. + Scientists and yeast companies have created new yeast stains that maintain desirable characteristics, yet don't produce H2S. + The sulfate reduction sequence isn't the only source of H2S in wine. High levels of elemental sulfur in the must can also cause reduction problems. AT A GLANCE ne of the most interesting of all wine faults is reduction. Reduction is caused by the pres- ence of undesirable volatile sulfur compounds, which include hydrogen sulfide, mercaptans (also known as thiols), thioesters and disulfides. These compounds are a real problem for winemakers because they produce a range of off-odors. What makes reduction particularly fascinating as a wine fault is that, in certain contexts and at cer- tain levels, volatile sulfur compounds also can add interesting complexity to wine. For example, there's the struck match/flinty note, caused by a mercap- tan, that is proving very popular in many Chardon- nays. And there are the polyfunctional thiols that are important in the passionfruit/grapefruit aromas that work so well in the context of Sauvignon Blanc. Nor- mally, though, winemakers will seek to avoid reduc- tion because it is negative most of the time. And when it's bad, it is horrible. New Yeasts for Reduction Management Researchers and suppliers introduce low hydrogen-sulfide-producing strains O BY DR. JAMIE GOODE