Post-harvest cleaning of equipment

One of the most important cellar activities regularly neglected due to time pressure is the cleaning and servicing of harvest equipment post-season. Ideally, the equipment should be stored away as soon as possible after use in a clean, dry condition and away from the sun. Moving parts should be greased or oiled, as this helps to prevent the parts from rusting while standing idle for months until the next season. The following article provides a few tips for cleaning the most important harvest equipment.

Sugar-sampling auger

Few things are as sticky as grape juice that has dried in the warm summer sun.

• Dismantle the whole auger as far as possible so it can be properly cleaned. Pay particular attention to the difficult-to-reach nooks and crannies where juice can often remain.
• Remove the flexi pipe and replace it at the start of the new season. The pipes tend to become brittle after a year’s use in any case. This causes leakages and can ultimately result in the pipe breaking during the next season.
• Store the unit in a safe place.

Receiving bins

• Make sure that all grapes have passed through the screw conveyor.
• Spray the sides thoroughly with water and ensure that all sticky juice has been washed off.
• If possible, cover the bin with a canvas which keeps dust, leaves and even pigeon droppings out of the container. This will simplify the next pre-harvest cleaning.
• There is usually also a bin covered with mesh at the front of the grape bin. Make sure that this bin and the pipe connecting it to the grape pump are open and clean.

Crushers

• Ensure that all side doors of the crusher are opened.
• Remove the basket and spindle and move out the rollers. Clean thoroughly and dry.
• Lubricate as required with food-grade grease and reassemble the crusher.

Stalk belt conveyor

• If belt conveyors are exposed to the sun, it is best to remove them and store away, as the material will become brittle from prolonged exposure to UV light.
• If they are standing in the shade, release the pressure on the belts, which will prevent them from shrinking over time. If this happens, it is difficult to work with the belts again the next season.
• Use the opportunity to grease the rollers and replace broken rollers.

Mash coolers

• Tartrate crystals build up on mash coolers and must be washed off properly at the end of the season with a calcium hydroxide solution. A solution of 1 to 2% is usually adequate.
• Next, neutralise the alkali with a 0.5% acid solution. Organic acids like citric acid work well, but can also serve as carbon sources for certain microbes. In this regard, inorganic acids like nitric or phosphoric acid would be preferable. Both have a good effect on stainless steel.
• Rinse thoroughly with clean water and drain completely so that all the lines can be stored dry. Stagnant water is a breeding ground for disaster.
• The same applies to the cooling water. Drain it completely from the system, otherwise it will stand still for nine months and become rotten.

Mash pump

• Make sure that the bottom drainage taps of the mash pump are open.
• If there is a plug, the best practice is to attach the plug to a chain so it doesn’t get lost. Otherwise, ensure that the plug is stored in a safe place where it is easily accessible for the next season.
• If possible, remove the stator of the pump and inspect it for wear and tear.

Grape pipelines

Many cellars have pipelines that can transport to various parts of the pressing cellar. Many of these lines are not necessarily used regularly.

• At the end of the season, ensure that all lines and routes are rinsed to make sure that no grapes or juice remain behind in the system. The rinsing of grape pipelines usually requires large amounts of water, but it is essential to rinse thoroughly to prevent the growth of unwanted micro-organisms in the cellar. The used water could be repurposed for irrigation in the cellar’s gardens.
• As with the mash pump and mash cooler, it is essential to ensure that the pipelines are fully drained and stored in a dry condition.

White wine separators

• Make sure that all taps and doors are fully open. The doors tend to occasionally swing shut.
• Remove all grape skins from under the conveyors, especially in the far back corner. Any grapes left behind there can become a breeding ground for unwanted organisms. Use a bright light to inspect, as the separators tend to be quite dark on the inside.
• If canvas tubes are used to connect the fixed grape line to the separators, it is a good practice to remove such tubes, clean them thoroughly inside and out, and store away safely for the next season.
• If the separators are cooled, it is also a good practice to drain cooling water from the equipment thoroughly.

Flotation machines

• Gelatin tends to become rock-hard when left standing for too long. Ensure, therefore, that the whole dosing unit of the flotation machine is rinsed with warm water so no gelatin is left behind in the unit.
• Open all taps and also make sure that the front filter is removed and cleaned well.

Red wine fermentation tanks

• As with the canvas tubes in white wine separators, the tubes must be removed and cleaned inside and out, after which these must be stored in a safe place.
• The pump-over sprayers should also be detached and properly cleaned.
• Ensure that all taps and doors are open and that no water remains in any part of the system.

Mobile mash pumps and screw conveyors

• Ensure that all the grape skins have passed through the conveyors and none remain in nooks and crannies.
• Open the drainage valves or plugs, and in the case of plugs, store them in a safe place for the next season.
• Store the mobile mash pumps in a place where they will stay clean and dry until the next season.

Wine presses

• After the last cycle of the season, the press must be rinsed out properly to ensure that all grape skins have been removed.
• Remove the juice channels if possible and wash off the tartrate crystals with a caustic potash solution, followed by a diluted acid solution and clean water.
• The press drum can also be rinsed with a low concentration of caustic potash and acid to remove tartrate crystals and colour, in the case of red wine.
• Rinse thoroughly with water to ensure that no chemical residue remains on the membrane.
• Leave all taps in an open position and store bladder presses with doors turned to the bottom.
• Also ensure that the juice collection tray under the press is clean and dry, so too any pumps and fixed pipelines attached thereto.

Last but not least – safety

• With all actions in the cellar, remember to always put safety first.
• Use and wear the correct PPE, especially when handling chemicals.
• Ensure that the power source of moving machines is securely locked out/disabled before working on or in the machine, press or tank.

For more information, contact Pieter Badenhorst at pieterb@fortheloveofwine.co.za.

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