The sulfites in wine and their effect on wine making
Sulfur dioxide (SO2) is a molecule consisting of one sulfur atom and two oxygen atoms. It’s a gas at room temperature and pressure, and it’s a natural component of the atmosphere. It’s also a byproduct of burning fossil fuels, like coal and oil. When SO2 is emitted into the air, it eventually makes its way into water droplets, which is why it’s present in rainwater.
SO2 is used as a preservative in wine, and it’s also used in other foods like dried fruits, as well as in pharmaceuticals and personal care products. It’s added to wine for a variety of reasons: to prevent spoilage, to protect against oxidation, and to stabilize color.
Sulfur dioxide has been used in wine for centuries, and its use is currently regulated by most national governments. In the United States, the maximum amount of SO2 that can be added to wine is 350 parts per million (ppm). In the European Union, the limit is 160 ppm for white wine and 210 ppm for red wine.
Some people are sensitive to sulfites and can experience symptoms like hives, itching, abdominal pain, and shortness of breath. These symptoms are more common in asthmatics and people with a history of allergies. Sulfite sensitivities are thought to affect around 1% of the population.
SO2 is not the only sulfur-containing compound used in winemaking. Yeasts produce other sulfur compounds during fermentation, including hydrogen sulfide (H2S) and mercaptans. These compounds can smells like rotten eggs, cabbage, or garlic. These compounds are typically removed during the wine-making process through a process called “racking,” which involves transferring the wine from one vessel to another.
Sulfur-containing compounds can also form during wine storage, and these compounds are typically responsible for “off” smells in wine. These compounds can be removed through a process called “active sulfite removal,” which uses a filter to remove the compounds from the wine.
Some winemakers choose to not use SO2 in their wines. These wines are often referred to as “natural wines,” and they can be more prone to spoilage and oxidation.Visit Site
The role of fermentation in wine making
The role of fermentation in wine making is to convert the sugars in grape juice into alcohol. In order to do this, yeast is added to the grape juice which then eats the sugars and produces alcohol and carbon dioxide gas. The carbon dioxide gas escapes from the fermentation vessel, taking with it any unpleasant aromas, leaving behind the wine.
The process of fermentation is essentially the same whether you are making red wine, white wine or rosé wine. The main difference is the time that the skins are in contact with the must (crushed grapes), as this affects the colour of the wine.
Red wine is made by fermenting the must on the skins for three to four weeks, while white wine and rosé wine are made by fermenting the must without the skins. This is because the skins contain pigments which give red wine its colour, and tannins which give it structure and body.
Tannins are found in the seeds, stems and skins of grapes, and they are an important component in wine making. They give wine its astringency, or dryness, and contribute to the ageing potential of a wine. Tannins are soluble in alcohol, so as a wine ages and the alcohol content decreases, the tannins become more concentrated and the wine becomes more astringent.
The fermentation process is complete when all of the sugars have been converted to alcohol. The wine is then racked (transferred) into a new vessel to clear it of the dead yeast cells and any other sediments that have fallen to the bottom of the fermentation vessel.
Depending on the style of wine being made, the wine may undergo a second fermentation, or malolactic fermentation. This is when bacteria convert the malic acid in the wine into lactic acid, which gives the wine a softer, rounder mouthfeel. Wines that undergo malolactic fermentation are usually red wines.
After fermentation is complete, the wine is ready to be bottled and enjoyed.
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