As shown by the results, biologically aged wine is a poorer acetification substrate than is young (unaged) wine. Previous work by our group revealed that, although acetic bacteria can use various sources of nitrogen, they tend to use l-proline,l-leucine, l-methionine and ammonium preferentially for acetification in some media (Álvarez-Cáliz et al., 2012; Maestreet al., 2008; Valero et al., 2005).