How Is Wine Made?

How Is Wine Made? A Comprehensive Guide

  • 01 of 09

    The Wine Grape Harvest

    Wine Grape Harvest Scene at Artesa Winery in Napa. Justin Sullivan/Getty Images

    The vineyards are a critical determinant in the end product wines for each and every vintage. Vineyards are like the wine's bassinets, where early grape life begins and flourishes, for all wine is truly birthed on the vine. The vineyard's location, climate, terrain, soils, vines and rootstocks, irrigation systems and pest management controls all factor into the final product in one way or another. Sun exposure and time on the vine both play a key role in the grape's development and specific sugar levels.

    Winemaking commences with the annual grape harvest and can be accomplished by either mechanical harvesting equipment or hand harvesting. Hand-harvesting affords more precise selection and often does a better job of protecting the grape’s juice content from oxidation due to damaged skins. Mechanical harvesters offer a more efficient, often cost-effective, process and are well-suited for large vineyards that lay on a flat patch of earth. The type of harvest - hand-picking, mechanical harvesters or a combination of the two, is largely influenced by the winemaker’s final wine style goals as well as budget.

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  • 02 of 09

    Crushing and Destemming

    Crushing and Destemming Phase of Winemaking. Justin Sullivan/Getty Images

    After the grapes have been harvested it is often a mad dash to get them crushed and destemmed. The objective of crushing is not necessarily to squeeze all of the juice out of the grape but to split the external skin and allow the juice to start its run, giving the sugar from the juice its first chance to mingle with the natural yeast found on the grape's skin. It's the combination of yeast and sugar that produces the wine's alcohol, via the yeast converting the sugar into alcohol and carbon dioxide. The "crush" happens in one of two ways:

    1. By mechanical means with a heavy spiraled steel roller.
    2. The famous grape "stomp."

    The grape stems are separated from the juice, or "must" as it is referred to at this phase in the game. This is also the juncture where red wine grapes and white wine grapes take different paths. If a wine is destined to be a red wine then the grape skins that provide the color characteristics and the tannin contributions for a red wine. If the goal is a white wine, then the grape skins are removed along with the stems at this phase of the process and the grapes are pressed prior to fermentation.

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  • 03 of 09

    Wine Fermentation

    Fermentation Tanks filling with Pinot Noir. Justin Sullivan/Getty Images

    This is the phase in the winemaking process that really gets wine going on its path to its ultimate destination ... the bottle! It is during fermentation that the grape's sugars are converted to alcohol and carbon dioxide, along with a good bit of residual heat that needs to be monitored to prevent distortion of flavors. The process of red wine fermentation typically takes place in stainless steel tanks, large vats or oak barrels. Maceration is basically the contact phase - where the must and the grape skins have maximum contact to produce good red wine color, structural tannins and extensive flavor components and nuances. The more the red wine grapes are in contact with their grape skins, the "bigger" the wine will likely be.

    White wine fermentation often takes place in stainless steel tanks with lower heat levels that are closely monitored and the oxygen levels strictly guarded (to prevent rapid oxidation). Chardonnay is one exception, some winemakers prefer to hold the Chardonnay juice in sealed oak barrels for fermentation to influence flavor development.

    If during the fermentation process the grapes were not quite ripe enough, sugar may be added to the must to increase alcohol levels in the final product, this addition is referred to as "enrichment". Likewise, acid can also be added to the must if the acidity is low, this is understandably referred to as "acidification." Also with white wine fermentation, an additional step referred to as "stirring the lees" is added. This step involves mixing up the residual yeast that is left post fermentation to yield more flavors.

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  • 04 of 09


    Press. S. Slinkard

    Pressing, usually done right after the crush for white grapes and after fermentation for red wine grapes, is basically taking the sticky grape solids left from either the crush or fermentation and squeezing them to get a very thick liquid that can be used to enhance both color and flavor of the presumptive wine to be.

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  • 05 of 09

    Malolactic Fermentation

    Malolactic fermentation is a process in which lactic acid bacteria converts the harsher malic acids in the juice into lactic acid to produce a softer mouthfeel and overall a more inviting palate presence. Most red wines go through malolactic fermentation to reduce their acidity and some fuller-bodied white wines are sent through malolactic fermentation (usually in the barrel) to mellow them out a bit more.

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  • 06 of 09

    Maturation of the Wine

    Oak barrel aging at Montecillo Winery. Stacy Slinkard

    The maturation phase of winemaking essentially represents the home stretch of a wine's journey from vine to bottle. When you think of the wine maturation process, inevitably traditional oak barrels come to mind and for good reason, both French and American oak, are the most common containers for the maturation process to take place. Oak offers protection, imparts flavor and does allow tiny amounts of oxygen to penetrate via the staves to both ease the tighter tannins in a red wine and create flavor complexity in both red and white wines.

    The other option for maturation is a stainless steel tank. This option is becoming increasingly popular as they are inert, economical because they do not need to be replaced after so many years in the rotation and they are easy to maintain. To compensate for the lack of oak in the stainless steel tanks, some producers supplement the process by adding oak chips to the juice shooting for the "oak effect."

    Racking is the process of moving the juice from one barrel to another, which provides two key benefits:

    1. The juice is separated from the bottom layer of sediment, which could negatively impact the final flavor.
    2. The wine undergoes a bit of aeration to open up flavors and allow for further development.
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  • 07 of 09

    Finishing: Fining and Filtration

    The finishing process involves several critical components. First, the finishing and filtering of the wine (collectively referred to as "clarification") removes the vast majority of the unwanted particulates still residing in the wine. Often egg whites are used in the fining phase to bind up tiny floaters in the wine and weigh them down so that they end up on the bottom of the barrel and can be separated from the wine.

    Filtration is the process of removing bigger solids like dead yeast cells and other particles so the wine is no longer cloudy, but bright and clear, as a consumer would expect.

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  • 08 of 09

    Blending Wines

    Drawing wine from barrel. Justin Sullivan / Getty Images

    Blending wine can be as simple as taking two separate wines and mixing them together to complicating things a bit by taking multiple varietals from multiple regions and blending them to make a new wine with a unique flavor experience. It likely goes without saying, that it takes a lot of experience and a very refined palate to successfully blend wines for today's worldwide market. A winemaker may blend wines for a variety of reasons: to adjust pH, acidity, alcohol levels, tannin content or to improve color, aroma or flavor.

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  • 09 of 09

    Bottling Wine

    Wine bottling line. Stacy Slinkard

    Finally, the bottling phase of winemaking - the end is in sight! Bottling wines today is done through mechanical bottling lines. Smaller wineries might rent bottling rigs that can be transported to the winery for the season, while the larger estates have their bottle lines onsite. As far as the actual process, the wine bottle is slowly filled and topped with either nitrogen or carbon dioxide to displace any oxygen that might be lingering on top of the fill line.

    The bottle is then capped with either a traditional cork or a modern screw cap, depending on the winery's traditions and philosophies. The bottles have their unique feature labels slapped on and away they go for either further bottle aging or straight to the case for distribution.