The solera system for aging is typically used in wine, brandy, and vinegar. It works by blending small portions of contents from barrels aged at different intervals. The finished product is a mixture of ages and the average age gradually increases over time and the process continues. Half of the contents of the barrels are poured out for bottling while the rest is left to age and blend with the next batch, increasing in age slowly over time, but making well-aged products very rare.