Earth

As any self-respecting Frenchman (i.e. those who remain citizens of France and who pay their taxes) will tell you, the basis of a good wine is ‘terroir’, that mystical ‘je ne sais quoi’ that embraces the interaction of geography, geology and climate of a certain place with the grape vine’s genetics, and which is here interpreted as ‘earth’. And most of us are aware that were it not for the biochemical endeavours of microbes, wine would just be dilute, non-alcoholic grape juice. But now it seems that it is not just the ethanolic fermentative activities of Saccharomyces species (‘yeast’) that are important in the quality of the wine that results, nor the vineyard’s terroir, but there are also much smaller-scale microbial factors at work. Mathabatha Setati et al. report differences in the fungal flora present on grapes within the same vineyard. This myriad of microbiological forms plays a pivotal role in pre- and post-harvest grape quality and contributes significantly to the final aromatic properties of wine. They also found that small differences between vines, such as in temperature or sun exposure, could significantly alter the composition of the fungal community on grape surfaces. All of which adds even more mystery and mystique to the vintner’s art. So terroirists be warned! And if the thought of this has you stroking your beard in faux rumination: don’t! Or you might be unwittingly adding yet another fermentative fungus to the mix, as demonstrated by brewmaster John Maier, of Rogue Ales (Newport, Oregon, USA), who has used a yeast found ‘clinging to the bristles of his 34-year-old beard’ to brew a beer with a ‘mild, fruity aroma’. If this has given you a thirst for more plant-based drinks knowledge, may I put in a plug for Amy Stewart’s forthcoming book, The Drunken Botanist, ‘an exploration of the dizzying array of plants that humans have, through ingenuity, inspiration, and sheer desperation, contrived to transform into alcohol’. I’ll certainly drink to that!