The Manufacturing Process

Wine Production was first  seen 6,000 years ago. But it wasn’t until 1857 that Pasteur correctly described the science behind fermentation and Wine Production. Because crushed grapes contain all that is needed to create wine, ancient wine producers simply allowed nature to take its course. As time went on, people realized that by intervening at certain times, they could make a wine with more predictable characteristics. The process of making wine is a manufacturing process. In general, the manufacturing process is comprised of the following processes:harvesting and crushing grapes; fermenting the must; ageing the wine; and packaging.

Photo Credit: Royce Bair

Harvesting and Crushing Grapes

Although red and white wine production involved slightly different steps that necessitated separate production lines, the winemaking process was similar for both types. Grapes can be harvested manually or mechanically—both with advantages and disadvantages; however, manual harvesting has many more advantages in terms of wine quality outcome. With manual cultivation, only the best grape clusters are picked, while mechanical cultivation cannot differentiate between a rotten grape and a good grape. Harvesting by hand, though it is slow, guarantees only the best grapes will be used to make wine, creating better quality but also a higher price tag due to extra manual labor. Mechanical cultivation allows for more grapes to be picked at a time and save the winery and ultimately the purchaser money.

Fermenting the must

Photo Credit: Daniela Ruppel

 After harvesting, all grapes usually transferred to the winery by truck for crushing. The pressed juice or “must” was pumped or gravity flowed into large temperature-controlled concrete, steel, or oak tanks for fermentation during which natural and/or added yeast metabolized the grapes’ sugar into ethanol and carbon dioxide. Fermentation typically lasted one to five weeks. The production of higher quality wines typically less automated and in smaller volumes. Lower quality wines made in larger volumes and more “formula” based. High-end premium producers were careful to keep grapes from different growers in separate fermentation tanks for quality control purposes. Jug wine producers typically used large, common vats for grapes drawn from several growers.

Aging the wine

Wine Bottle Aging by Huang S

After crushing and fermentation, wine needs to be stored, filtered, and properly aged. In some instances, the wine must also be blended with other alcohol. Many wineries still store wine in damp, subterranean wine cellars to keep the wine cool, but larger wineries now store wine above ground in epoxylined and stainless steel tanks. The tanks are temperature-controlled by water that circulates inside the lining of the tank shell. Other similar tanks are used instead of the old redwood and concrete vats when wine is temporarily stored during the settling process. (Bralla, 2007) Aging the wine for the right amount of time creates a more approachable wine—especially in red wines with lots of tannins—with new oak flavors including sweet vanilla, leather, tobacco, and spices such as clove, anise, cinnamon, or pepper. Many wine drinkers like the flavors and aromas oak imparts. Wine softens during barrel aging. Aging for a long time will slowly oxidize the wine in a controlled manner.

Packaging/Bottling 

Before bottling the wine, more sulfates are added to ensure that additional fermentation will not occur in the bottle.  Then, corks or screw caps seal the wine, with an added capsule making this seal more secure. Labeling wine has become very important in recent years. Eye-catching labels sell wine, regardless of if it is a good wine or not.  The cover of a book may be beautifully designed, but not a good book. The same goes for wine, the label on a bottle of wine may be gorgeous, but the wine may be poorly produced.