Most wineries keep their excess wines down in a cave underground because caves provide the ideal temperature and humidity levels to allow the wine to sit for months (or even years). However, most wineries don't show you this part of the operation. Rombauer Vineyards, just outside of St. Helena, does let you see this. We didn't get a full tour (that is only for people who reserved in advance) but what we could see was really interesting. Rows and rows of wine barrels just waiting to age and be delicious. We learned a lot from our tour guide about how much work it takes to make a barrel of wine - did you know it takes 8 gallons of water to make a bottle of wine from start to finish?