Vinification or winemaking is a term used to describe the winemaking process. Vinification will vary depending on the type of wine being produced, such as reds, whites, sparkling or sweet. Although the vinification process is fairly consistent, winemakers have considerable latitude to experiment with their talents to produce newer, more innovative wines that showcase each vineyard’s unique qualities.
The vinification process includes all the steps necessary to get the grapes from harvest to bottling. Some variations occur depending on the type of wine being made.
Central to the process is fermentation, the conversion of the grape's natural sugars into alcohol and carbon dioxide.
Vinification can be roughly divided into what happens before, during, and after fermentation. Below is a brief sketch of the most important points.
The type of grape and when to pick it are two of the most crucial decisions a winemaker will make at the start of the vinification process. Grapes can be harvested either manually or mechanically. Manual harvesting is labor-intensive and not commonly used. Mechanical harvesting provides a faster, larger harvest and allows for the entire crop to be picked at once.
The skin of the grapes is broken to release the sugary juices, exposing them to the yeasts for fermentation.
There are generally two types of fermentation in wine, which may or may not take place simultaneously.
The grapes are then transported to the winery for preparation and primary fermentation. Primary fermentation is achieved by many different avenues that are dependent on the type of grape and the winemaker’s preference. Fermentation takes place when yeast enzymes convert the natural grape sugars into alcohol. It ends when the sugar supply is used up or the alcohol present kills the yeast enzymes.
Malolactic fermentation is a biochemical process that takes place when the hard malic acid present on ripe grapes is tempered with a weaker lactic acid. Bacteria present in the wine activates this process. Red wine commonly undergoes malolactic fermentation to smooth out its natural acidity, and some complex whites will also benefit from this process.
Racking is a process that removes the leftover sediment that settles in wine after fermentation. The wine is drained into another container by way of a system of levels, or racks. As it goes through each rack, the wine gives off less and less sediment until it is deemed suitable by the winemaker.
After fermentation, wines can appear cloudy with leftover residues. Fining is a process which clarifies the wine. Fining agents are added to the wine, which in turn adhere to the residues and send them to the bottom of the vat. Common fining agents include egg whites, tannin, gelatin, bentonite, isinglass and casein. .
- Cold Stabilization
Cold stabilization gets rid of fine deposits in the wine, known as tartrates. Wine is placed at very low temperatures which prevent the tartrates from forming. Some winemakers argue against the process. They see the tartrates as proof of a more natural wine versus one that has been heavily processed.
Filtration occurs when wine is passed through a medium that captures particles larger than a certain size. It is the final clarifying step after racking and fining to ensure a quality bottling. Since filtration is both expensive and time-consuming, many winemakers keep this process to a minimum. Racking and fining take precedence to keep costs down, as well as being gentler on the wines.
Bottling wine has become more high-tech and complex over the years, speeding up production to accommodate larger harvests and increased demand. The process begins with sterile bottles. The automated lines fill the bottles, cork, capsule, label and box the wines. Some use a device that can detect abnormalities and impurities before boxing.