The creation of a high quality wine is a combination of science and art, as a wine maker uses their vast base of knowledge, augmented by their intuition and tastes to create the best wine they can. Of course, it's aided by a bit of luck, as even a master can only do so much with poor materials (or a poor vintage, in this case).
The quality of the wine depends on the quality of the grape. Good growing conditions, skilled care in the vineyard, and the ever elusive terrior play a role, before the wine maker has a chance to work their magic.
A skilled wine maker knows what to do with that grape, what to do to bring out its natural aromas and flavors, and how best to turn the simple juice into a complex wine.
The details about a high quality wine can be argued, but for us it boils down to complexity in the glass. A good wine will be flavorful or refreshing, but a truly great wine will bring layers of flavor and encourage you to sit and contemplate the glass.
There is constant arguing about whether anyone can actually tell the difference, with studies supporting both sides. This week we had a chance to run our own informal test: two bottles of Californian Cabernet Sauvignon with drastically different price points. Shared with family, we gave them a taste of each and asked for their thoughts. The results followed our thesis, but it still wasn't universally agreed which was the better wine. In this case, we know who was wrong (the one who disagreed with us!). But it does go to show that all that really matters is what you enjoy!