While harvest season mostly evokes images of a horn-of-plenty filled with squashes and autumn vegetables, it’s also a poignant time in the year of a winemaker when all the careful cultivation comes to an end.

After the warm, humid summer brings ripening to the vineyard (a time your wine enthusiast friends might call “veraison”), harvest season marks the transition from growing to mashing, fermenting and aging. Starting in September, wine growers north of the equator begin the process of de-graping the vines and getting ready for the fermentation and aging process that turns a sweet fleshy fruit into one of the worlds most beloved beverages: wine.

As a general rule of thumb, grapes used in lighter reds and whites are harvested earlier in the season, on the bridge of summer and fall. Meatier grapes, like those used for cabernet and shiraz enjoy a longer growing season, hanging out on the vine until as late as November. Later harvesting typically mellows bright, acidic flavors, which are less prominent in these varietals.

If you’ve ever been berry picking, you’ve probably wondered exactly how some of the more mainstream wineries get thousands of bottles of wine out each year without having ten thousand hands picking grapes. For wineries engaged in mass production, harvest season has gotten ridiculously more efficient with the introduction of agricultural technology, like machine harvesters. While many wineries still do it the old-fashioned way—combing the vineyard for the perfect bunches of grapes—others opt for a nifty machine that shakes the vines and collects the grapes as they fall off.

Once the grape is plucked, the unique characteristics that will give a particular vintage its unique terroir are essentially frozen in time. The climate and growth factors that influenced each grape have left indelible marks on the quality and taste of the wine the grapes will create. As for the vine, it will continue producing fruit annually; however, a newly planted vineyard will typically bear no fruit for three seasons.

Viniculturists have many considerations to make when choosing the right time to harvest. A few days can make a significant difference in the character of the grapes, and there is scarcely a way to tell exactly what the profile of any one vintage will be. Winemakers take into account the density of the foliage and its effect on how much sunlight reaches the grapes. Additionally, as seasons change, daily temperature fluctuations and the duration of daylight can change quickly. All of these factors make selecting harvest time an art that is literally cultivated over years of practice.

As you enjoy heartier wines this fall, research some of the growing and harvesting practices of your favorite winemakers to understand how it impacts the flavor of the wine. You’ll be surprised to find similarities among varietals across labels when wines are made from grapes harvested in similar ways at similar times.