... except that solera aging has been with us for around 500 years. Primer: solera is a Spanish word, actually a name for the barrel (or series of barrels) used to age a variety of liquids both alcholic and non-alcoholic: sherry (originally - hence the Spanish etymology), wine, madeira, beer, whisky, rum, vinegar, and brandy. What makes this different from other barrel aging (aside from the fact that solera barrels or "vats" tend to be enormous) is that anytime a liquid is drawn from the barrel, a sizable percentage is left in to age with the next filling. This means that over time - and some producers have been doing this for decades - you have a very complex, very rich, very old liquid that is unlike anything you get from single-barrel aging and maturation. It's basically old and new all at the same time, like a 1964 Mustang running with modern enhancements.