Making wine is a fascinating and artful process that requires a lot of hard work, precision, passion, and patience. Each winery has a different approach depending on the production size and the style of wine made. From growing the best quality fruit to fermentation, and ageing, read on to discover the secrets and basic steps of the wine-making process.
Stage 1 – Harvest
Great wine is all dependent on the quality of the grapes, and the moment they are picked determines the wine’s flavour, including sweetness and acidity. Knowing when to pick the grapes is vital, and if you end up waiting too long, the weather might ruin the fruit. The grape quality is affected by many things, including the weather, the time of harvest, and the soil.
Harvesting in the Northern hemisphere tends to occur between August to November, while in the Southern hemisphere, it is typically from mid-February to early April. However, it is essential to note that harvesting also depends on the type of grape, climate conditions, and the type of wine. Sweet and decadent dessert wines, for example, are harvested at the end of, (or even after), the season as the sugars need to be highly concentrated. In contrast, grapes for a sparkling Cremant are gathered around mid-august. Grapes can be hand-picked or harvested through machinery, which is generally preferred to speed up the process when producing wine on a mass scale. However, hand-picked grapes tend to have less skin breakage.
Stage 2 – De-stemming And Crushing
Grapes grow in bunches on vines, meaning that they have stems. While not always the tastiest, some can offer added complexities to wine and provide many options for winemakers in their production. The stems can provide unique flavours, tannins, and textures during cluster fermentation (when the grapes are left whole).
For example, if they are very ripe, the produced wine can have a more spicy or woody flavour. In comparison, underripe stems can lead to more herbal notes. Even though the stems can provide extra flavour, they are most commonly removed before the grape bunches‘ arrival to the cellar for production. But depending on the wine, the winemaker may choose to throw in a group of unstemmed bunches into a tank of already de-stemmed grapes.
Crushing whole clusters of ripe grapes is typically the following step. Today, mechanical crushers tend to perform this time-honoured tradition of stomping the grapes into the commonly referred must.
Stage 3 – Pressing
Pressing involves the extraction of the grapes‘ juices. When pressed, the skin and juice (pomace) release free-run juice, which is of high quality and used to make wine.
White wine grapes are pressed to break and separate the skins before fermentation, while reds tend to be pressed after. When making red wine, the skins and juice are in contact while in the fermentation tank for colour, structure, and flavour and help the red wine to extract tannins. The process usually occurs at the same time as de-stemming.
Stage 4 – Fermentation
Simply put, the equation for fermentation is: Yeast + sugar = Alcohol and CO². This happens through the yeast converting grape juice into wine. The yeast eats the naturally occurring sugar found in the grape juice, causing it to release alcohol and carbon dioxide. This tends to begin naturally once the grapes are crushed due to wild yeast present on the grape skins. However, the process needs to be streamlined as wild yeast isn’t always predictable and can lead to incomplete fermentation, so most winemakers use cultured yeast to ensure reliable results.
The winemaker maintains a temperature of 15-18℃ for white and rose wine and 22-25℃ for red, while the yeast multiplies and feeds on the sugars. Alcohol levels are dependent on the sugar content, and roughly 16-19 grams of sugar per litre is needed to produce wine with 1% Alcohol by Volume (ABV).
If sugar levels do not reach the desired amount, the winemaker may add extra sugar to increase alcohol levels, a process called chaptalization. As the alcohol levels rise, the fermentation process stops due to the yeast becoming dormant. The wine has residual sugar leftover in sweet wines, while nearly all sugar is fermented for dry wine variants.
Stage 5 – Clarification/Draining And Ageing
Once the fermentation process is concluded, the winemaker must cleanse the wine from sediments, including pomace and dead yeast, that can settle to the bottom of the fermenting tank. To do this, the wine is transferred from one barrel to another. Some winemakers use filters; however, this can affect the overall taste.
Others perform fining, where substances such as bentonite or clay are used to absorb or bind with any solids that settle to the bottom of the tank.
After the wine has been cleansed, it is aged to improve with time. As the wine matures, chemical processes occur, resulting in the creation and addition of various flavours. Wine is typically aged in either wine bottles or oak barrels to create a wine with more earthy notes. Although it depends on the wine you’re ageing.
American oak, for example, brings out a vanilla aroma, while French oak barrels infuse the drink with a subtle and spicy aroma.
Stage 6 – Bottling
Once the wine is clarified and aged to the winemaker’s taste, it is then bottled to be ready for distribution. Manufacturers can use various methods for the bottling process, including machinery for larger production sites. Tinted bottles tend to be used to keep out the light and prevent any damage. It is good to know that the wine goes through regular, vigorous checks during the process, with the winemaker monitoring its quality before it gets bottled.
Concerning the sensory profiles of the wine amid the bottle ageing process, it largely depends on the added flavourings. For instance, a flavoured Shiraz wine could still be discriminated from their corresponding control wines.
Additives such as potassium sorbate are sometimes added before bottling to prevent fungal growth in sweeter wines.
While this is a general guide to the wine-making process, it is essential to note that the processes will vary. Each type of wine will have a different approach. Many things can happen along the way, and each winemaker will ultimately tailor the wine-making process to their specific needs, requirements and ethical standards.