Those huge chunks of ice that are in your drink…
House made shrubs and custom or small-batch bitters are just some of the ingredients that craft cocktail makers are using to add flavor to their drinks. One other popular technique that I’m coming across more and more often is barrel aging cocktails. I’ve seen bars offer both spirits that are aged in-house and complete cocktails that are aged. Wines need to be aged because the juice needs to ferment and the flavors need time to develop. When it comes to cocktails, though, they are usually aged just to give them a different flavor profile and pull in notes of caramel, vanilla and (of course) actual oak from the wood. Different types of barrels and different treatments of the wood will impart slightly different flavors.
If the bar is working with large batches of a drink or spirit, aging can be done in a large oak barrel. If they are working with smaller quantities, it is much more likely that they are using oak chips or an infusion spiral to generate that flavor. The aging process can take anywhere from a few days to a few weeks, depending on the type of barrel or infusion stick used (newer barrels impart flavor much more quickly than previously used barrels) and the amount of liquid you are trying to age (a barrel full of liquid will take longer than a jar with a stick in it).
When aging cocktails, ingredients like fresh juice or soda will be omitted before aging. Juices can go bad – unless the bar is doing a very fast aging – and sodas will lose their potency. Spirits, bitters and even shrubs are fair game for the process and will form the base of a barrel aged cocktail, with additional juices or garnishes added just before serving.