People often think sorting refers to a belt or vibration table, but BeveraTech technical sales manager Anton Oosthuizen says that’s quite wrong.
The Kanonkop team in front of their sorting line, from left: AEV vibrating hopper, incline conveyor, Oscillys XL, TRV Vibrating table and Vistalys optical sorter.
A new approach to grape sorting
By Johannes Richter
“It’s about the whole process. You’re essentially removing percentages throughout the line – each piece of equipment removes a certain percentage, and at the end, you’ve sorted 98-99% of your berries.” Due to budgetary constraints, implementing a comprehensive sorting line is often impossible from the start. The answer lies in making gradual improvements over time, which requires understanding how each link in the chain contributes holistically to the sorting process.
The sorting line
Producers usually begin with a hopper or bin conveyer that receives the grapes from bins, tippers or crates. Speed can be a problem if grapes are not being received and conveyed at a steady rate. “A consistent motion is important,” Anton says. “Constant delivery to the destemmer yields best results.”
Adding a vibrating hopper, tilting hopper, or vibrating table (with or without a hopper on top of the table) between the conveyer and destemmer can significantly help clear unwanted material. Vibrating hoppers/tables rely on variable-speed mechanical movement and are simple, quick, and practical. An intermediate sieve is often added to capture usable juice.
Destemmers
The destemmer is probably the most essential equipment in the sorting line. BeveraTech supplies a range of Bucher Vaslin destemmers and guides clients in making informed decisions based on their needs and budget. The mechanism for rotary destemmers hasn’t changed much in over a century and still consists of a rotating perforated drum and beater shaft that separates the berries from the stalks.
The new generation of oscillating destemmers, such as the Delta Oscillys from Bucher Vaslin, have made the rotating cage and shaft superfluous and rely only on an oscillating cage for much cleaner and more precise stalk separation.
“The oscillating movement works with gravity to separate ripe berries by size and weight,” Anton says. “This even keeps berries that seem ripe to the naked eye on the stems, but on close inspection, they are subpar. So, although it’s a destemmer, it also performs a sorting function by removing raisins and green or unripe berries.”
Depending on the process, BeveraTech often suggests another vibrating table for a second cleaning pass. While two-in-one or three-in-one destemmers include a mechanism that cleans the grapes after destemming, like the Oscillys, clients are often surprised at just how much waste remains, Anton says. “The truth is, they don’t see it because it goes straight into the pump. Our machines are there to ensure cleaner grapes, so that’s what we emphasise.”
Beyerskloof is an example of a winery that used to rely only on a destemmer, but this resulted in many stalks, small green berries and raisins ending up in open vats along with good grapes. “This had a huge effect on the fruit, tannin structure and balance of our wines,” winemaker Anri Truter says. “Over the past five years, we’ve installed two sorting tables – one for whole bunches and one for berries – and replaced the old destemmer with the Delta Oscillys. The difference is incredible – basically, there are no stalks, green berries or raisins in the vats. Our wines now have much cleaner fruit aromas, better balance and no green flavours. I feel sorting is necessary for top-quality wines, especially after you’ve put a lot of effort into the vineyard and want the cleanest product before fermentation.”
The optical option
Optical sorting is at the cutting edge of berry selection. An adjustable algorithm and high-definition camera detect and remove anything that deviates from specified parameters with a focused blast of compressed air. BeveraTech is currently the only agent with an optical sorting machine in the market – the Delta Vistalys – with eight in service since 2012. It’s a niche product, and berries must be pretty clean when they reach the optical sorter; otherwise, collateral damage is possible when debris is not removed.
The technology is expensive, but BeveraTech offers a viable alternative. The Delta RFlow system comprises a vibrating table, a belt for destemmed grapes, and a separator/cutting bar that ejects unwanted material. Its air-blade function changes the trajectory of lighter leaves, grapes, and low-density material so that they pass under the cutting bar while good berries simply pass over it.
This action can be adjusted according to the output of the preceding process, which is why BeveraTech always first conducts a complete assessment of the entire production line before making recommendations. “We don’t just sell equipment. We sell a process and help producers make an informed decision,” Anton says.
Kanonkop used to sort by hand over vibrating tables until the volumes made it unfeasible. The winery has since expanded to include almost everything it needs to ensure only the best-quality grapes reach the wine. And they haven’t looked back. “We started using the new technology in 2017, which includes a roller system under the destemmer, vibrating tables and an optical sorter,” winemaker Abrie Beeslaar says. “For me, it’s straightforward. Look at the material the machine removes, and you won’t want to work any other way again.”
Click here to see the feature as published in the May 2024 issue of Wineland Magazine.
