Wine Spectator reports a yeast strain has been found that "produces lower-alcohol wine." The article got my attention because too many wines are marred in some way by high alcohol. However, too many wines are also ruined by residual sugar. So, I read the article.
Wineries have a vested interest in bringing down alcohol levels because wine is more heavily taxed once they cross a certain percentage. According to the TTB, over 14% alcohol by volume the tax rate moves from $1.07/gallon to $1.57/gallon. That's a significant jump.
There is leeway to adjust the number by choice, however. The Electronic Code of Governmental Regulations (a little less than halfway down the page in case you're the one person actually clicking these links) states that below 14% alcohol a producer has 1.5% leeway to claim a different alcohol. Above 14% the option reduces to 1%. So, if your wine tips the scale at 15% just label it 14% and pay the lower tax. If you're 15.1% you're out of luck or you need to lie. I am convinced that some zinfandel producers adjust up to make the wine seem more powerful and intense.
Anyway, other than that simple method to "reduce" your alcohol content, this yeast strain is another option.
"The yeast in question, Metschnikowia pulcherrima, was singled out from a pool of about 40 different species chosen for their ability to ferment sugar and produce ethanol under anaerobic conditions during four days of culture. But Metschnikowia pulcherrima, or AWRI 1149, achieved the greatest balance of lower alcohol and negative side effects." (Wine Spectator, from the article linked above.)
One of the side effects is ethyl acetate, i.e. smell of nail polish. I'll take fruit aromas with a little heat on the nose from alcohol over that any day.
Science can keep trying to dissect and fully understand the process of turning grapes into wine but I firmly believe there is some synergy and maybe even magic that will never be completely understood, and I like it that way. In the meantime wineries, if you want to lower your alcohol percentages, just do what the government allows. 14% pinot noir? Violà 12.5%. 15% chardonnay? No problem...abra cadabra, 14%! Now that's magic.