INCORPORATING COLD CHAIN |
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It is not clear if this was scientifically proven or just what was mostly available and found to be suitable. However, it was also noted that it is generally accepted that higher storage temperatures, if held relatively stable, can be quite acceptable for extended periods.
Pandell( 1996) published a research paper that concluded that if the storage temperature was increased from 13 ° C to 23 ° C, the ageing process of wine quickened by a factor of between 2 and 8, depending on the wine. His conclusions indicate that the lower the temperature, the longer wine takes to age, but given steady temperature and acceptable conditions, moderately cool temperatures are acceptable.
Experience in the industry has also found that not only temperature, but also humidity is a concern where wine is aged in barrels. Low humidity causes excessive loss of wine through evaporation, leading to increased costs of barrel handling required for topping up.
In a climate such as South Africa’ s, where natural conditions will not allow adequate temperature control for barrel storage, some form of mechanical air conditioning needs to be applied to maintain the
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DESIGNING A CONTROLLED ENVIRONMENT
Bosman has gained a reputation for always seeking out the latest and greatest technology— not only in their agricultural practises but also their winemaking. Petrus Bosman is experimenting with an entire range of innovative things, using energyefficient equipment throughout the farm.
As such, he has been keen to try out a new type of barrel they saw in Spain: an alternative to the traditional wooden oak barrel commonly used throughout the world. These 1 500l vessels * are made from plastic and are square shaped, claiming various benefits and cost savings.
To properly conduct this new‘ experiment’, he needed a controlled environment in terms of temperature and humidity for the various types of wines he had in these imported new plastic‘ barrels’. He contacted Marius Louw of Louwco Cooling Solutions in Wellington, with whom he has had a long-standing relationship, to assist with a cooling solution for this new store.( The room also houses pallets of bottled wine, ready to be shipped out to various areas.)
There was a room requirement of 20 ° C inside with a minimum humidity of 70 %( with 34 ° C dry bulb and 19 ° C wet bulb
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COMPARING THE OPTIONS
Seeley International has spent a lot of time and research working on solutions tailor-made for the wine industry. As such, they did a study comparing three cooling options: direct evaporative cooling; refrigerated air conditioning; and indirect evaporative cooling.
1. Direct evaporative cooling Traditionally used in hot dry climates and characterised by:
• Limited temperature control of the space, typically a minimum of 25 ° C to 27 ° C.
• Increased humidity in the conditioned space.
• 100 % outside air is used to cool the space.
• Cooling performance is adversely affected by ambient conditions of high relative humidity( RH).
• Modest capital cost of installation.
• Low power requirements.
• Low cost of operation.
2. Refrigerated air conditioning Applicable for most climates and characterised by:
• Precise temperature and humidity control is possible.
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conditioned space.
• Closed cooling— cools the internal air, and draws little or no outside air.
• Operates in all climates if designed correctly.
• High capital cost.
• High power requirements.
• High operating cost.
3. Indirect evaporative cooling Very effective in hot climates that are dry and those that are moderately humid and characterised by:
• Much lower temperature of supply than a direct evaporative cooler.
• Good temperature control available.
• No additional moisture added to or removed from the conditioned space.
• 100 % outside air is used to cool the space.
• Usable in moderately humid climates.
• Moderate capital cost.
• Low power requirements.
• Low operating cost.
BOSMAN’ S( COST-EFFECTIVE) SOLUTION
Louw, who previously used Seeley’ s
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desirable environmental conditions. |
temperatures outdoors). |
• Removes moisture from the |
products in agricultural applications |
Inside Bosman’ s new‘ barrel’ store. |