South Africa Wine Technical Yearbook 2025

Example of a checklist: • Ensure that the top lids of both the tank pumped from and the tank pumped to are open before the pump is switched on. • Ensure that the correct tanks are worked with as specified on the job card. • Ensure that the volume of each tank correlates with the volume indicated on the job card. • Ensure that the receiving tank is properly cleaned before pumping wine into it. • Ensure that the receiving tank’s lid is properly closed after the wine transfer and that the lid seals well. • Report any leakages observed on the tank the wine was pumped from, so these can be fixed before wine is pumped into the tank again. Oxygen control in cellars Excessive exposure to oxygen can cause oxidation and subsequent spoilage in wines. It is therefore critically important that high dissolved oxygen levels in wines are prevented. The saying ‘prevention is better than cure’ is apt in this regard. Here are a few tips: • Use cylinders of carbon dioxide (CO 2 ), nitrogen (N 2 ) or dry ice to displace oxygen from receiving tanks. Formulas and advice exist regarding the amount of dry ice to be used given the surface of your tank’s bottom, and how long to apply the gas. • If you are just starting to fill the tank, the pump should initially be set to a slow speed. Where the wine enters the tank, there is usually a lot of turbulence and this can possibly lead to excessive oxygen uptake. If the wine level gets to approximately 20 to 30 cm above the bottom, the pump can be set faster. • It is not desirable to leave a wine tank less than 100% full for a period of longer than a day or two. It does however occasionally happen that this cannot be avoided. The best practice in such cases is to apply a protective layer of CO 2 or N 2 on top of the tank. Equipment is available to help distribute the gas evenly across the tank. Even distribution is very important for the effectiveness of the gas. • When bottling of a full tank is initiated, it is also a good practice to apply a protective layer of CO 2 or N 2 on the

wine when the tank is approximately half full. This helps to ensure that even the last litre bottled out of such a tank cannot be spoiled by oxygen. Cellar pumps In the previous cellar mistakes article, pumps were also discussed. Here are a few more tips regarding pumps and their application: • Make sure that the pump used is suitable for the type of product to be pumped. Different types of pumps are required for wine, wine lees, washing chemicals and grape concentrate. The lifespan of pumps can be extended and the quality of the cellar’s wine maintained by using the correct pump for each action and restricting its use to that action only. • No pump is built and intended to be used at 100% of its capacity all the time. Neither the pump nor the wine benefit from a pump working too hard, bouncing around frantically while the wine is pumped. This should be kept in mind when pumps are purchased. If the objective is to pump 30 000 litres within an hour, a pump should be purchased that can pump about 40 000 litres per hour at its maximum capacity. • Pumps are manufactured and released with a certain size fitting. For example, a 65 mm fitting. Never use a pipe with a pump of this size that is smaller than 50 mm. In the case of a 100 mm pipe, nothing smaller than an 80 mm pipe. Using smaller pipes will only create unnecessary pressure on the pump, which is detrimental to its lifespan and wine quality. • Suction pipes should be as short as possible and in good condition. If the pipe is damaged in any way, air can be sucked in. The weak spot can also cause the pipe itself to be sucked in and this can damage the pump. In conclusion, it is the little foxes that spoil the vineyard. Regardless of how minor the mistakes highlighted here are, the more they are identified and prevented, the better it is for a cellar’s wine quality and economic sustainability. 

For more information, contact Pieter Badenhorst at pieterb@fortheloveofwine.co.za. Reference https://www.wineland.co.za/tips-to-avoid-the-most-common-cellar-mistakes-part-2/

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TECHNICAL YEARBOOK 2025