This isn't your average sherry vinegar. This Cepa Vieja from Vinagres de Yema has a mother vinegar that's been aged in an oak barrel for 40 years.
The Cepa Vieja is made from the harvest of Palomino grapes grown near Jerez, Spain. The vinegar is aged in a wood barrel or criadera. Each criadera contains vinegars with similar flavor characteristics but have been aged for different lengths of time. When the solera–the barrel with the oldest vinegar–is tapped for bottling, it is never fully drained. Instead, the remaining vinegar is then blended with vinegar from the next younger criadera, and so on through the series of bottles until the youngest is topped off with fermented must. The resulting flavor is slightly woody with a rich, smokey-ness.