Whether the vine is a clone, a cross, a mutation, or a hybrid, it follows a certain annual growth pattern.

• If you visit Napa Valley in February, the vines are somewhat unexciting — no grapes, no leaves — but the vines are by no means inactive. Spring has almost arrived, and as the soil temperature begins to rise, the roots begin absorbing water from the soil. This activity pushes sap through the vines, and you can often see this sap oozing out of what is left of the pruned canes from the previous year. Certain soil types warm up faster than others, and this can influence when the vine begin to weep, or push sap.

• About a month after the vine begins to weep, roughly the end of March or early April, the buds open. When the previous year's fruiting canes are pruned off, a remnant of that cane is left behind, and on that remnant are buds, which form the foundation of the following year's crop. Bud break signals the beginning of the new vintage.

• By the month of May in the northern hemisphere, you can see embryo bunches on the canes that have emerged from the buds. These are the grapevine flowers. When they bloom and self-pollinate, the grapes begin to emerge. Growers have a general idea of how large the crop will be at this point. Frost is a major threat.

• It is now late May to early June. The vine has flowered and fertilization has taken place. This can be stressful time for the grower, because steady temperatures in the high 60s to low 70s are necessary for the vine to flower successfully. If it is windy, cold, or excessively damp, the vines will flower unevenly, which can affect the quality of the grape clusters. Frost is still a factor.

• Before June is over, the grapes themselves will have set. At this point you can see actual clusters of grapes begin to take shape on the vine. Different varieties of grapes, such as Riesling and Cabernet Sauvignon, vary in terms of the number of grapes each embryo bunch produces.

• As the grapes ripen, red grapes take on their color (white grapes more or less keep theirs), and grape acidity levels drop and sugar levels rise. This process is called verasion. By August this is well underway.

• Harvest in places such as Napa Valley can begin in late August. Grapes such as Sauvignon Blanc and Pinot Noir will start arriving at the winery. Grapes such as Cabernet Sauvignon ripen later due to their thick skins, but usually all grapes are off the vines by the end of October. The danger here is for an early rain shower to douse the grapes and cause rot, so growers must be very careful.

• After harvest, the vines slip into dormancy, and growers prune off the fruiting canes to make room for new ones. Pruning also helps maintain the vines' shape and preserves their precious supply of resources. The whole cycle then repeats!