How Wine Is Made

Italy, France and Spain lead the tables of global wine production, with Italy making an inconceivable 49.1 hectolitres in 2020. But how do they make wine? How is wine produced? Corkscrews at the ready, we’re diving in to discover just how wine is made.

Engineering How It’s Made
29 June 2022

While wines originate from different regions, and how wine is made can differ for a range of reasons, the main categories they fall into are red wine, white wine and rose.

So, how do they make wine? The process of how wine is made – known as vinification – has been around for centuries. And, while each winemaker or “vintner” will have their own particular practices, there are some standard steps they’ll follow, including harvesting, crushing, pressing, fermentation, clarification, ageing and bottling.

But how is wine made? How is wine produced on a grand scale? Are there different answers to “how is red wine made” and “how is white wine made”? What about “how is rose wine made”? Oh, we’ll get to that and more.

How is Wine Made? It’s all about those Grapes

It is said that the most important aspect of how wine is made is not a question of “how is wine produced”, but the quality of the grapes used. The grape quality or “terroir” is determined by a combination of factors, beginning with its variety.

Amongst the species of grape, some are more commonly used in winemaking than others. The common grapevine, Vitis vinifera, fills the most bottles worldwide, but this comes in many varieties and in both purple and green colours.

In terms of “how is white wine made” versus “how is red wine made”, white is made from green grapes, red from purple. And the names of those grapes are stated on the bottle. For example, Cabernet Sauvignon and Pinot Noir grapes are purple, Pinot Grigio and Chardonnay grapes are green. And what about “how are rose wines made?”

Beyond grape variety, elements including the soil makeup, growing season weather and harvest method are all integral to the quality of the end product.

How is Wine Produced? Harvesting

Vineyard on rural hillside (Photo: Jacobs Stock Photography Ltd via Getty Images)

Harvesting is the process by which the grapes are picked, and the first step in making wine. The time of harvest is an important factor in the quality of the end product. In the northern hemisphere, harvesting usually takes place from early September up to early November. The harvesting season in the southern hemisphere usually runs from mid-February to early March.

Before they are picked, grapes are checked to ensure they have reached the perfect level of ripeness. Acidity, sugar levels and taste are all considered in a mix of scientific process and grower experience. This is a delicate balancing act. If picked too early, the grape will be sour. If picked too late, the grape will be raisined.

Harvesting can be carried out either mechanically or by hand. Some estimate that up to 90 percent of the world’s wines are mechanically harvested. This is done by tractors that shake the vines to dislodge the grapes, which land on a conveyor belt that transports them to containers. This is both cheaper and faster than handpicking, but is indiscriminate in judging quality, while there can also be the inclusion of extra materials such as leaves, stems, stones and insects. It can also damage the grapes.

In some cases, handpicking the grapes is a legal requirement. For example, in the
French region of Châteauneuf-du-Pape, all grapes must be handpicked. This means manually removing the grape clusters from vines, and allows for discernment as to what’s actually picked.

How do they make Wine? Destemming and Crushing

Crop and juice ready for wine (Photo: istetiana via Getty Images)

The question “how is wine made” conjures up visions of barefoot stomping on grapes to crush them, but this is rarely the reality nowadays. Instead, this is usually automated. Crushing is gentle squeezing of the grapes to break the skin, and destemming is separating the grapes from their ranchis or stem. While crushing and destemming can be two stages, they are now often done by the same machine. The harvested grapes are transported to machines that destem and crush them using paddles, rollers and a corkscrewing blade inside a tube. The resulting pressed grape juice with seeds and skins is called ‘must’.

How is Red Wine Made vs How is White Wine Made?

Winery workers treading red wine (Photo: Morsa Images via Getty Images)

The answers to “how are red wines made”, “how are white wines made” and “how are rose wines made” diverge at this point. For one thing, white wines often skip destemming and crushing altogether. And if they are crushed, they often include stems in the crushing process. Meanwhile red and rose production removes all the stem matter prior to crushing because they contain a lot of tannins, white wine making often leaves them in.

However, the main difference in making wines of assorted colours is the use of the grape skin. The colour of red wine and rose is derived from the skin colour. Therefore, red and rose wines are fermented with the skin and seeds of the grape, but white wines are fermented without.

How is White Wine Made?

The crushing phase is completed as quickly as possible after the destemming so as to minimise the juice’s exposure to the skin and seeds. Some white wines skip these stages entirely to avoid any contact.

How is Red Wine Made?

To imbue red wine with its colour and flavour as well as tannins, the juice, seeds and skin are left together for longer.

How is Rose Wine Made?

As in the answer to “how is red wine made”, rose wines are made from red grapes. The difference is that the colour is not extracted to the same extent. The winemaker allows the juice as much time in contact with the skin and seeds as they deem required to get the desired colour.

How Is Wine Made? Pressing

Pressing mostly applies to white wine. If red wines are pressed, it is usually done after primary fermentation (the next stage). Also, if the crushing stage is effective enough, some wines will skip this stage.

Pressing is applying pressure to the must, or sometimes to whole grapes, to extract the juice. This usually means sandwiching between two surfaces, one static and one moving. One common press is made up of a perforated cylinder surrounding an inflatable tube. Once the grapes enter the cylinder, it rotates, the tube is inflated and the grapes or must are pressed between the two.

How do they make Wine Alcoholic? Fermentation

Wine barrels in wine cellar (Photo: Juan Silva via Getty Images)

Fermentation is the stage where juice becomes wine. It is something that would occur naturally to the juice, but in regard to how wine is made commercially, it’s usually carefully managed. Here, there is another difference in answering “how is white wine made” versus “how is red wine made”.

Fermentation involves placing the juice in containers until all the sugar within is turned to alcohol. It is the process whereby microorganisms (such as bacteria) will convert carbohydrates such as sugar into alcohol or organic acids.The type of container differs for white and red wine. Generally speaking, white wine is placed in stainless steel vats, while red is housed in oak barrels. There are numerous exceptions and variations, but the reason is oxidation. Oak barrels mean more oxygen, stainless steel less. The period of fermentation can last from a few days to several years depending on the grape type, storage and desired wine. Most wines will ferment within 10 days to a fortnight.


Grape harvest bucket with red wine bottle and wine glass (Photo: MEDITERRANEAN via Getty Images)

Clarification is about removing any remaining solids from the wine. Most of the wine will be drained from the tank or barrel through a filter. Any remaining bits and pieces are sent to a bladder press to squeeze out the remaining liquid.

Some wineries use a chemical clarification process. For example, adding clay to the wine will cause solids to stick to it.

Ageing and Bottling

Some wines will be bottled immediately, while others are allowed to age within oak barrels or stainless-steel tanks. The choice of container tends to mirror that of the primary fermentation process, but ultimately depends on the intended taste of the wine. This stage is often referred to as secondary fermentation and can last anywhere up to 15 years. Once ready, machines insert the wine into bottles.

Phew, that was thirsty work, but that was the lowdown on how wine is made. The next time you blearily eye that bottle of Pinot, you’ll know the answer to “how do they make wine”. Now it’s just a matter of finding the corkscrew…

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