Growing Grapes:
Grapes grow on vines. There are many different types of grapes, but the best wine grape is the European Vitis vinifera. It is considered optimal because it has the right balance of sugar and acid to create a good fermented wine without the addition of sugar or water. It has been said that the wine is only as good as the grape; a poor winemaker can ruin good grapes, but a good winemaker isn't going to make great wine from inferior grapes.
Now before I say anything else about grapes, let me point out an error I have made in drafts of this document (and for all I know it may persist--proofreading is an art). That is the difference between "varieties" of grapes and "varietals." The word "varietal" means "of or pertaining to a variety." Types of grapes are "varieties." Wines made from a single variety are varietal wines. So, for example, a 100% Cabernet Sauvignon wine is a varietal. The cabernet sauvignon grape, zinfandel grape and merlot grape are varieties of grapes. (Of course, don't be confused that, for example, United States law allows a wine to be labeled Cabernet Sauvignon so long as it has at least 75% of that variety of grape. Now, is that clear?)
Vines start producing grapes about three years after planting; a useable crop after five years. They reach their prime in terms of crop yield between ages ten and thirty. Vines can grow for a hundred years, though production is reduced as they get older. However, reduced production (which is also caused in other ways--growing in poor soil, lack of irrigation, pruning the vines, climate, etc., the so-called "stressing the vines") can lead to "better" wine. So some very good wines come from "old vines."