Nickolas Bokulich and his colleagues at the University of California, Davis, analysed the microbes on 273 samples of must – the crushed grapes from which wine is made. These came from eight wineries across the four major growing regions in California in 2010 and 2012. Just as wine flavour varies by region and grape type, so do the microbes present. Lactic acid bacteria was most common in Napa and on Zinfandel grapes. These bacteria can spoil wine by causing "mouse urine" flavours, or improve it by turning malic acid into lactic acid, which adds tanginess. Zinfandel grapes also had larger populations of yeasts that improve the "complexity" of wine. To read more, click here