Microbial Dynamics in Sour–Sweet Wine Vinegar: Impacts on Chemical and Sensory Composition

The most known and traditional vinegar is the one that is made from wine. For its production, the grape must undergo alcohol fermentation and the posterior oxidation of ethanol to acetic acid. Yeasts and acetic acid bacteria (AAB) carry out the biochemical processes in sequence. The process of wine acetification can be achieved by slow traditional processes (the Orléans or French methods) or by a quick submerged industrial process. High-quality vinegar is usually produced by traditional methods using oak casks, once the wood allows the continuous aeration of the acetic bacteria culture. Sour–sweet vinegar presents a balance of both bitter/sour and sweet flavors. The sourness typically comes from acetic acid, while the sweetness can come from the type of fruit or the amount of sugar present at the end of vinegar production. In general, sour-sweet vinegar has a more complex and nuanced flavor profile compared to regular vinegar, which is often simply sour. One kind of vinegar produced by wine acetification where yeasts and bacteria co-exist and produce savory vinegar is traditional balsamic vinegar (TBV), from Italy. In Spain, fortified sherry wine has also been used for vinegar production. In Portugal, some wine companies have produced port wine vinegar since 2018. These three distinctive vinegar products have in common the sweetness that can be found, well balanced with the acetic acid sourness. In this review, we analyze the sour-sweat wine vinegar process, bearing in mind the possible interactions between yeasts and AAB that occur during vinegar production and considering the symbiotic or competitive features of a diverse microbiota.