What affects wine quality? The answer to this question isn’t so simple. A number of different factors, from the age of the vine’s rootstock to the vineyard’s climate, can dramatically impact how a wine tastes and how long it will last in your cellar. If the winemaker starts off with underripe, poorly grown grapes, then the resulting wine won’t taste elegant or refined, even if the producer ages the wine in the finest French oak. To invest in the highest-quality wines on the market, it’s a good idea to understand some of the growing techniques that affect wine quality, including climate, vine age, soil composition, pruning, weather, and harvest dates. By considering each of these factors as you shop for collectible wine, you’ll learn how to identify the best wines from the top producers–and be able to pick out unlikely gems from lesser producers as well.