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Wine improves with Moly and time

26/02/2019

Acid-resistant molybdenum-grade stainless steel vats and related equipment are essential in the production of many alcoholic beverages. They are used in alcoholic fermentation, vinification, aging, storage and transport. Hygienic and easy to clean, they help producers from high end to mass market, creating refined and well-crafted libations.


Photo credit: © Domaine Etienne Simonis / photo Benoît Facchi

As the world population has grown, global alcohol consumption has risen to its highest level ever. However, the annual per-capita consumption has remained relatively level in recent years at 4.3 - 4.7 litres of pure alcohol. Spirits account for approximately half of the total, followed by beer (35%) and wine (8%). Although the beverages and their processes are very different form one another, they all require hygienic, specialized equipment.

Each beverage's raw ingredients, be it grapes, rice or berries, and the processing steps dictate the optimal material for the process equipment. Stainless steels offer excellent hygienic properties, corrosion resistance, cleanability, durability and lightness of weight. Importantly, they also do not taint the product's taste or colour and therefore dominate the alcoholic beverage equipment market.

Alcoholic beverage production starts with must, mashes or worts – mixtures resulting from pressing, boiling or malting raw ingredients. Their chemical properties, in particular their acidity, dictate the optimal choice of the stainless steel grade, although alcohol itself is not corrosive. The starting musts and mashes are fermented to produce the alcohol, a process typically carried out in stainless steel vats. The material must be resistant to chemical attack and satisfy the specific requirements of the alcohol produced. The same is true for the other stages of production before and after fermentation. These differ for each type of beverage, but wine requires the most complex and most delicate process of all.

Wine is made by fermenting a 'must' obtained from pressed grapes and is often matured in vats or barrels. White wines' natural acidity is much higher than that of red wine. The combination of high acidity and SO2, added as an antioxidant, increases the corrosiveness of the must and wine. Therefore, Types 316 and 316L stainless steel, with 2% molybdenum for improved corrosion resistance are preferred for making white wines, champagnes, dessert wines, fortified wines and rosés. Red wines are less corrosive and so Type 304 stainless steel is usually sufficient for the vats and is most widely used. However, Type 316L is utilized for fermentation vat lids where the CO2 gases from the process concentrate.

The easily cleaned and sterilized stainless steel vats improve food safety and prevent defects in the wine more effectively than vats made of competing materials such as wood, concrete or resin, and at a lower cost.

Read more about the molybdenum's role in the production of wine, spirits and beer in MolyReview.

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