Stainless steel barrels make wines richer and more mellow
With the growth of the world’s population, the global consumption of wine has reached an all-time high. In recent years, the annual per capita consumption of pure alcohol is about 4.3-4.7 liters. The consumption of hard alcohol accounts for about half of the total, beer accounts for 35%, and wine accounts for 8%. Although alcoholic beverages and their production processes vary widely, they are inseparable from the special production equipment for sanitation.
There are many kinds of raw materials for wine production. The raw material of the wine is grapes, the raw material of Japanese sake is rice, and the gin is added to the juniper. Winemakers strive to pursue the highest quality of wine while ensuring consistency between batches and years. The ingredients and process steps of each wine determine the optimum material for the process equipment. Stainless steel has excellent hygiene, corrosion resistance, cleaning performance, durability, and light weight. In addition, they do not destroy the taste or color of the product. Therefore, stainless steel has become the leading material for wine production equipment.
Alcohol fermentation knowledge
In the alcohol fermentation process, the yeast decomposes the sugar converted from the sugar or starch contained in the plant itself, converts the sugar into ethanol (alcohol) and carbon dioxide, and releases heat to raise the temperature of the vat. Temperature has a great influence on the fermentation rate. Below 10 ° C, the yeast cannot multiply, and above 35 ° C, the activity of the yeast rapidly decreases, and the fermentation may stop. Between these two temperature limits, the fermentation rate is doubled for every 10 °C increase in temperature. The time required to produce the puree wine varies from a few hours to a few days depending on the final product.
Resistance to chemical corrosion
Alcoholic production begins with grape juice, mash or wort, which is a mixture of raw ingredients that are pressed, cooked or made into maltose. Although alcohol itself is not corrosive, their chemical properties, especially acidity, determine the choice of stainless steel grades. Grape juice and mash fermentation produce alcohol, a process usually carried out in stainless steel barrels. The material of the fermenter must be resistant to corrosion and meet the special requirements of alcohol production. Other processes before and after fermentation have the same requirements for materials. Different types of wines have different requirements, and the wine process requires the most complex and finest.
White wine protection aging process
The grape juice obtained by crushing the grapes is fermented into wine, usually aged in a barrel. White wine is made from white grapes, and red wine is made from red grapes. Both grape juices are clear and transparent. When red wine is brewed, the red grapes are immersed in ferment with the belt seeds to give them the color and aroma of the red wine.
White wines need to be more elaborate than red wines at every stage of brewing because they are more unstable and more susceptible to oxidation. In order to better protect the subtle fruity aroma of white grapes, top wineries even pick white grapes at night. Slowly squeeze gently in a pneumatic press made of 316L stainless steel to avoid the bitter taste of tannins after the grape skin and grape seeds are crushed. Most white wines use only grape juice. In order to preserve the fruity, the grape juice is fermented for 10-14 days at a temperature of 18-20 ° C, which is lower than that of red wine. Fermented at 12-13 ° C for up to one month, it produces a white wine with a finer and more balanced taste. The heat adjustment device installed in the barrel can precisely control the fermentation temperature.
White wines have a much higher natural acidity than red wines, and white wines are more susceptible to oxidation. When the grape juice is pumped from one container to another, the grape juice oxidizes when it comes into contact with air. Therefore, it is necessary to add an antioxidant sulfur dioxide (SO2). SO2 is not only an important antioxidant, but also a good fungicide for some microorganisms, so it is used throughout the wine production process.
High acidity plus SO2 increases the corrosiveness of grape juice and wine. Therefore, the corrosion-resistant 2% molybdenum-containing 316 and 316L stainless steels are the preferred materials for brewing white wines including champagne, dessert wines, liqueurs and pink wines. Due to the weak corrosiveness of red wine, the vat can be made of 304 stainless steel, which is the most widely used. However, the fermenter lid should be made of 316L stainless steel because the carbon dioxide produced during the fermentation will collect on the lid.
During the storage and aging process, stainless steel barrels that have been in acid and SO2 environments for a long time are intact. This means that there will be no release of the can into the wine, and the wine can be upgraded by its own aging. Since the tank is sealed, it also prevents excessive oxidation of the wine during the aging process.
Stainless steel barrels are easy to clean and easy to disinfect, which improves food safety. Compared with wood, cement or resin materials, it can prevent wine from appearing more effectively and at a lower cost. The 316L stainless steel mesh can be used to filter out impurities before bottling without changing the taste of the wine itself.
Corrosion resistant wine barrels for pure alcoholic beverages
In fact, any plant can produce wine by fermentation distillation. Food, vegetables, fruits, sugar cane and agave are all famous brewing materials. The basic step in the production of spirits is to add yeast to ferment the raw materials, and the fermented mash is distilled to obtain ethanol. 316L stainless steel barrels are used in high acidity mash to produce spirits. The stainless steel fermenter allows for tight control of the fermentation process and is easy to handle and clean.
Whisky fermenters range in volume from 1000 litres to over 5,000 litres. Traditional fermenters are woody, but stainless steel barrels are more cost effective and easy to empty, maintain and clean, preventing “bad yeast” bacteria and mold contamination. Wood fermenters are infected with mold, and the mirror-polished inner wall of the stainless steel barrel helps to thoroughly clean and seal.
Brandy and gin made from fruit and aromatic plants are sometimes also impregnated with 316L stainless steel drums to enhance the aroma of the wine and store it. For example, brandy produced in Alsace, France, after 6-8 weeks of immersion, placed in a 316L stainless steel tank for more than six years of outdoor aging, making the brandy more aromatic and mellow. Some Japanese sakes have been aged in the same way for 10 years.
Beer isolated from air and pollution
Beer is the world’s most consumed alcoholic beverage, fermented from wort. Wort is a mixture of water and germinated barley, ie, malt and hops. Yeast is sprinkled into the wort and fermented in a stirred fermenter. Fermentation is carried out in a strictly controlled temperature range and in an oxygen-free environment, depending on the type of beer produced. Beer must not be in contact with air from fermentation to drinking, so the equipment must be completely sealed. Sometimes, after fermentation, it is aged at 0 ° C for 3-6 weeks to mature and produce carbon dioxide. The standard grade used in the brewery is 304 stainless steel. However, in the case of higher corrosion resistance, 316 stainless steel or even 2205 duplex stainless steel is required.
Which is best for wooden barrels, concrete or stainless steel barrels?
Wooden barrels have been used in the production of alcoholic beverages for hundreds of years. Wooden barrels enhance the color and taste of wines and spirits. The barrel is still necessary when it is necessary to age the barrel, but this is one of the few uses left in the barrel. Wooden barrels are susceptible to microbial contamination and cannot be completely leaked, and maintenance costs are high.
In the 20th century, people used cement barrels to produce spirits and wines. The cement barrel has good thermal stability, low price and high plasticity. However, maintenance is difficult. It needs to be sprayed with an inert epoxy resin, even with a stainless steel lining to resist chemical reactions. Once the cement bucket is sealed, it is almost impossible to move, which is a fatal flaw.
In recent years, stainless steel has almost replaced all competing materials in the production of alcoholic beverages because of its strong advantages in installation, production operations and maintenance. Stainless steel is easy to manufacture and can be customized in a variety of shapes (cylindrical, curved, square, tapered or compartment). The stainless steel barrel can be attached to the bracket, and the bottom plate can even be hung from the ceiling. They are lightweight and easy to move, optimizing production layout. An integrated external coil or heating jacket precisely controls the temperature during the critical fermentation period. Good sealing prevents oxidation of the product. Stainless steel is hygienic, neutral to food, easy to disinfect, and can be fitted with pumps, thermostats, pipes and valves. Moreover, designers can use stainless steel to create a fascinating production site that attracts visitors.
Alcoholic beverages have been in production for thousands of years. The materials used in the past are easily polluted and prone to bacteria, and few wineries can produce high-quality wines. The taste of the wine is often unpredictable. With the widespread promotion of stainless steel processing equipment, many problems have been solved. Today, high-quality wines of all price points are available, and molybdenum-containing stainless steel plays an important role.