The Beginner’s Guide to Vinification

Vinification is the process of turning grapes into the alcoholic beverage we know and love as wine. This process happens via fermentation. Vinification is an activity nearly as old as human civilization itself! A 2017 discovery found evidence that humans made wine as early as 8,000 years ago.

These days, aspiring winemakers and enthusiasts go through years’ long courses in vinification. As an art and science with astounding depth, we’re obviously only going to skim the surface of vinification here. In fact, some people spend their entire lives training to become a master sommelier. This prestigious title requires an exam that as few as 3% of people pass. These masters are so knowledgeable about wine that they can correctly guess the region and year of the wine simply by tasting a glass of it. Thankfully, one does not need to be a sommelier to make wine – programs exist that teach students how to make wine.

vinification, fermentation

Oak barrels ferment wine. Photo by Leo Hau via Pixabay.

Selecting Grapes is the First Step in Vinification

Viticulture is the process of growing the vines and grapes themselves. Vinification begins with selecting the desired grapes that viticulturists have grown. There are a handful of important considerations when selecting the correct grape for the desired wine.

First, the variety of grapes is of utmost importance. If you want to make a chardonnay wine, you must begin with a chardonnay grape. When making a wine with multiple kinds of grapes, winemakers select varieties based on their tannin and sugar contents, aroma, and other flavor factors.

Winemakers also choose between the same grape variety based upon the region where the grape was grown. Different regions produce grapes with different terroir. Terroir is “the combination of factors including soil, climate, and sunlight that gives wine grapes their distinctive character.” A genetically identical vine grown in California, Chile, France, and Australia will all produce grapes with subtly unique tastes.

Other factors winemakers consider when selecting grapes are the age of the vines, the weather of that particular growing season, and the price of the grapes.

grapes, vines

Grapes hang from a grapevine. Image by Bruno via Pixabay.

Harvesting the Grapes

Once a winemaker selects grapes, the next step in the vinification process is harvesting the grapes. The perfect ripeness of the grapes differs based on the winemaker’s preference. Factors that indicate a grape’s ripeness include the color of the grape, stem and seed maturity, sugar content, acidity, and of course, overall taste. Sometimes winemakers don’t have the ultimate say in when grapes are harvested due to unforeseen factors such as labor shortages, wildfire smoke, disease. and pests.

vinification, pressing grapes

An old-school grape press squishes the juice out of grapes. Photo Rúben Gál via Pixabay.

Crushing and Pressing the Grapes

Surprisingly, crushing and pressing grapes are two different processes. First, the winemakers crush the grapes, either through human stomping or mechanical means. This crushing allows the juices within the grapes to mingle with the outside of the skins of the grapes. These skins contain tannins, which are chemicals that give red wines their sour, astringent, puckering taste. Red wines sit in their crushed juices for longer than delicate white wines.

Once the crushed grapes have had enough time to mingle with their skins, winemakers press all of the juice out of the grapes. Some makers use human-powered mechanical means, but most use commercial wine presses. These presses remove the skins and seeds from the juice. This name for this juice is must in the wine world.

Fermentation is Crucial in Vinification

Ah, fermentation; the stage we’ve all been waiting for. Fermented beverages, such as kombucha, beer, kefir, spirits, and wine, are found around the world. Grapes and must have high sugar content. Yeast turns these sugars into alcohol, carbon dioxide, and heat during the fermentation process.

Wine fermentation can occur in a variety of situations. Most familiarly, winemakers use oak barrels to ferment the must into wine. However, other options do exist. Some wines ferment in open-air containers where natural, air-borne yeast colonizes the must. Some large-scale operations use large, stainless steel containers as fermentation vessels. Carbonated wines, like champagne, even ferment inside the wine bottle itself.

Winemakers can choose from dozens of strains of yeast to ferment their wines. These different kinds of yeast, along with the fermentation vessel, duration and temperature of fermentation, and initial must affect the flavor, complexity, and uniqueness of the resulting wine.

Keep it Cool During Fermentation

The temperature of the fermentation room drastically impacts the resulting wine. Since fermentation produces heat, wine cellars without temperature control can often get too hot for quality wine. Red wines ferment best between 68 and 86F. White wines like it cooler, below 59F. When the yeast ferments above these temperatures, it can cause undesired byproducts that “have been associated with aromas or flavors reminiscent of rotten eggs, cooked cabbage, skunk, and landfill” according to PennState Extension. High temperatures during fermentation also increase the chance of bacteria spoiling the entire batch of wine.

Winemaker Ryan Pedvin stands in his fermentation room, whose climate is controlled by Coolbot.

Proper Storage is Also Part of Vinification

When a winemaker deems fermentation complete, they bottle the wine. However, most wines continue to mature once in bottles. The flavors of wine continue to develop as the beverage sits in the bottle, sometimes for decades. Winemakers often keep these bottles in a cellar for a few months or many years before selling them to the public. Then, consumers may store their wine for additional years until the right occasion to drink it.

As with fermentation, wine shouldn’t be stored at high or low temperatures. The best wine storage temperatures are between 50-60F. This is much cooler than the typical ambient room temperature in a house, especially in the summertime. Wine should never be kept above 60F for more than a few weeks for optimal storage. If you don’t have the luxury of a below-ground wine cellar, which will naturally stay around 60F year-round, it’s easy to make an economical, temperature-controlled space using a temperature controller like the Coolbot.

Vinification is a practice with immense depth and nuance. Hopefully, you walk away from this article feeling a little more confident about the main steps of vinification. The chemistry of winemaking, cultural practices between regions, and a variety of tools and machines will have to wait until next time. Now go enjoy a glass of white, red, rosé, or bubbly and think about the complex process of how it went from a grape to the delicious drink in your glass.

A Coolbot temperature-controlled unit is a great way to create the ideal wine cellar.

Featured image by Moni Quayle via Pixabay

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