Winemaking is both an art and a science, as it combines the creative hand of the winemaker with the chemical-focused process of grape fermentation. The fermentation process for almost all types wine is fairly straightforward: yeast is added first to grape juice, and then the yeast consumes the grape’s sugars and converts them to alcohol via carbon dioxide and heat.
While each grape variety has its own identifiable characteristics, it is actually the winemaker that creates the style, flavor, and personality for the finished wines. Because each style of winemaking can differ from one winemaker to another, there is no fixed recipe for making Chardonnay, Cabernet Sauvignon, although there are only general guidelines that should be followed to make a proper bottle of the alcohol.
The winemaker often uses a variety of techniques to best express his or her style in making wine. The following stages below depict the fundamentals of winemaking, and within this framework exists the options that the winemaker can take to add his or her style.
Every winter harvest time is an important moment for the wine’s vegetative cycle. Grapes are harvested and placed into boxes or bins, which are then delivered to wineries and stored in open containers called gondolas. Grapes are harvested either by hand or by machine, although most sophisticated wineries tend to use hands for picking grapes. Almost all major wine manufacturers that produce less expensive wine tend to use machines for harvesting in order to get more grapes in the factory per day.
After storage, grapes are then conveyed to a stemmer, a machine where grape leaves and stems are removed. Once the leaves and stems are removed, the grapes would then go to the crusher, where the necessary parts of the grapes are crushed. Some wineries allow grapes to bypass the stemmer and go directly to the presser or crusher for whole berry pressing. However, whole berries tend to have a much bitter flavor due to the added stems and leaves in the presser.
After crushing and de-stemming, the harvested grapes are put into the fermentation vats, which may vary in size from 50 to 5000 gallons. These vats are where the alcoholic fermentation of the grapes takes place. Most red grapes go to the fermenter first before pressing for primary fermentation (the process of converting sugar into alcohol and CO2) while most white grapes are pressed prior to fermentation. Some white grapes are fermented in small oak barrels for added aroma and flavor, and yeast is then added in the barrels to start fermentation.
Some winemakers prefer to utilize the native yeasts that are present on all grapes. These native yeasts are called non-Saccharomyces, which are supposed to indicate that they are not Saccharomyces cerevisiae, the main species of yeast that is primarily used for winemaking but is not naturally found in grapes. Some wine enthusiasts prefer wines that are fermented using natural yeasts, as they believe that the fermenting ingredient retains the rich characteristics and flavor profile of the grapes. However, using Saccharomyces cerevisiae for fermentation is much easier to do, since the amount of natural yeasts on grapes is often not enough to properly ferment wine.
After fermentation, the wine undergoes racking, a process wherein the wine is transferred to another container (usually a new oak barrel) without the use of the pump (which can sometimes affect the flavor of the wine). Some wines would sometimes stay inside oak barrels without racking so that it will continue its development until bottling.
More and more producers are still using traditional oak barrels for barrel ageing, while others would choose to keep their wine in large stainless steel tanks for extra durability. After barrel ageing and before bottling, some wines would be fined and filtered to help stabilize and clarify them. However, some wines are not fined or filtered so that it would have a richer and stronger flavor.
Bottling is the last stage before the slow and relatively lengthy bottle ageing process. Wines are bottled in a sterile or clean environment, and then they are sealed with a natural cork, screw-cap, or man-made cork. Natural cork is used by high-class wineries since it is more durable and more suitable for long-term bottle ageing, while screw-caps and man-made corks are used for less expensive wines.
By following the steps above, winemakers would surely be able to create a refined and flavorful wine. Some of the winemakers would usually add or change several processes in their winemaking to make their products more unique, although there are still some wine enthusiasts that prefer traditional winemaking. Not all wines have the same flavor despite following the same processes, as the location of the harvested grapes and the measurements for each procedure can greatly affect the flavor of the wine.