TECHNOLOGY: Innovation In Wine And Juice
Recent Western Cape Business News
Afrox has introduced a new design of a sulphur dioxide (SO2) cylinder head specifically for the local wine industry, which allows the user to draw the gas from the cylinder in a vertical position using a full length dip tube. This represents a major advance, both in terms of safety and accuracy, on the traditional method of inverting the cylinder.
Jaco Coetzee, Afrox Product Manager Packaged Chemicals, says the new-generation cylinder, which also has application in the fruit juice manufacturing sector, is environmentally responsible, reducing emissions of SO2 to the atmosphere via on-site scrubbers and eliminating the conventional “bucket and chuck-it” concept.
“SO2 is an important compound in winemaking, serving as an antibiotic and antioxidant that protects wine from spoilage by bacteria and oxidation,” says Coetzee. “It also helps to keep volatile acidity at desirable levels and is a very important element in winery sanitation. Wineries and equipment must be kept clean and since bleach cannot be used in a winery, a mixture of SO2, water and citric acid is commonly used to clean and sanitise equipment.”
The new Afrox SO2 cylinder, the result of 18 months of research and development, allows Afrox to provide a total solution to the winemakers through a direct injection process into the vat, significantly boosting accuracy of measurement. This safe and efficient process also facilitates the use of a variety of different cylinder packed sizes.
Coinciding with Intervitis Interfructa Southern African 2009, Afrox will host a winemaking expert from its parent company, The Linde Group, who is coming to South Africa to identify areas where cutting-edge European winemaking gas applications could be applied, bringing with him Linde’s broad international experience in the winemaking industry and an in-depth knowledge of the group’s exhaustive portfolio of wine applications.
Rob de Zoeten, applications engineer at Afrox, says: “We have established a strong reputation for identifying needs in the wine industry and responding to them with innovative solutions. We have resources throughout the country’s winemaking regions and an excellent track record of applying our gas products to help local winemakers achieve the highest quality fine wines. Our suite of products has been very successful in minimising oxygen exposure in this industry — from harvesting of grapes in the vineyard, right through the winemaking process and down the line to bottling and sealing of the finished product.”
Before the winemaking process even begins, oxidation is kept at bay by chilling the grapes as soon as they have been harvested, with Afrox’s patented carbon dioxide SnowShooting® system or by applying cryogenic liquid nitrogen at the winery. This chilling process reduces the rate of chemical degradation significantly before crushing. During this phase, SnowShooting® is not only an ideal blanketing medium to displace oxygen, but also serves to chill the substrate, slowing down chemical reaction rates. This inert carbon dioxide atmosphere — or the alternative, a liquid nitrogen atmosphere — minimises exposure to oxygen and chills the substrate during the crushing process. Liquefied gas is the best choice in this phase of winemaking and can be piped directly into the press.
The ingress of oxygen while transferring the substrate down the production line is an unavoidable threat to the quality of the end product. Afrox’s solution is to introduce small bubbles of nitrogen gas or a mixture of carbon dioxide and nitrogen gas at several key points in the process, to release dissolved or entrained oxygen. Diffusing nitrogen or a nitrogen/carbon dioxide gas mix as a sparging or de-sorption agent into wine or must, reduces dissolved oxygen levels and limits the degeneration of wine quality. Argon, an expensive inert gas, is less commonly used in this process.
Carbon dioxide (CO2) is used to purge tanks before the carbonic maceration process begins. Because of its density and laying effect, CO2 is also widely used for ullage blanketing, while its high solubility delivers a perfect effervescence to both white and red wines. CO2 snow from SnowShooting®, CO2 pellets or dry ice can also be floated on the mirror of the wine to form an inert buffer to displace oxygen as the level of wine rises. Alternatively, CO2 gas can be used to pre-purge the tank. Nitrogen gas, because of its inertness, can be used in a convenient and novel way in nitrogen pigeage (turning the cap to drown aerobic bacteria and encourage cuvaison).
To avoid oxidation when wine is being pumped from vessel to vessel during the production process, Afrox recommends using nitrogen gas as the transferral vehicle by means of a transfer tank omitting a sparging operation.
Oxidation remains a threat during this phase, as temperature and atmospheric changes affect the volume of the tank ullage. Nitrogen gas or a mixture of CO2 and nitrogen or argon ensure that the ullage can breathe, compensating for such fluctuations. In a tank management system Afrox offers a choice between a gas bleeding system, a gas demand system or a gas timed purge system.
In macro/micro oxygenation, very small amounts of oxygen are bubbled through red wine in tanks at a controlled rate after the malolactic fermentation stage or even during the maturation stage. This colour-stabilises the wine, ensures more body as a result of the softer and richer tannins and facilitates aroma integration and lowering of reductive flavours. Oxygen is introduced via a sparger at a rate of one to ten millilitres per litre, per month.
To eliminate oxidation during filling, fillers should run on counter-pressure with nitrogen, or carbon dioxide/nitrogen gas mixes and by pre-purging filling lines. Bottles can be inerted by pre- or post-fill purging with nitrogen, by using Afrox’s liquid nitrogen droplet dispensing system or by using CO2/nitrogen gas mixes.
Rob de Zoeten and his team will be manning the Afrox stand at Intervitis Interfructa Southern African 2009, at the Cape Town International Convention Centre from July 28 – 30 2009.
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