Optical sorting in two different line configurations

When drawings were made in 2019 for a new storage facility at Maatschap Fazembra in Emmeloord, a new sorting line was included from the outset. The trusted shake grader from 2001 was due for replacement and no longer kept pace with the farm’s capacity requirements.

“We were running at a capacity of eight to ten tonnes per hour,” says arable farmer Gert- Jan Haenen. “That meant we were sorting practically all winter, from lifting to planting. We also wanted to integrate optical sorting into the line.”

That step was taken recently. At the end of October, Haenen commissioned a new Tolsma-Grisnich sorting line for sorting around eighty hectares of seed potatoes annually.

A flexible sorting line

The line combines a mechanical size grader with an Optica Q optical quality sorter. Product can reach the Optica Q via four different routes: directly from the size grader, via a 6.5-tonne buffer bunker, through a separate bunker, or via the box tippers.

“For example, lots with more soil go through the buffer bunker, while batches that skin easily don’t. Lots that are sensitive to bruising go via the box tippers to minimise drop height. Off-sizes can be checked later if needed. This way, I can choose the most suitable route for each batch.”

Easy operation

A tablet mounted on the forklift allows one operator to control the entire sorting process. Routes can be selected, and the sensitivity of the Optica Q can be adjusted. The machine takes five images of each potato and assesses them for diseases, defects and shape deviations.

A smart algorithm compares these images with a database fed by 150 Optica Q sorters worldwide. The grower can then set how strictly the system sorts, on a scale from zero to one hundred. In a single pass, the product is divided into three outputs: marketable seed, clods, and feed-grade (B quality).

The system allows the farmer to scroll through the last two thousand potatoes, each with five images.

“This way, you continue to understand the machine and can easily fine-tune the process.”

Continuous learning

Every image captured by the system contributes to smarter AI models. Regular software revisions are carried out. A recent update improved the detection of holes made by wireworms in potatoes, and the system can also be trained further using images from atypical batches.

“Behind the scenes, our team is continuously training the software,” adds Jens Salomons, account manager at Tolsma-Grisnich. “We do this together with our customers. It’s a strong collaboration, because we all want the system to perform at its best.”

Meanwhile, the Tolsma-Grisnich Customer Service Team monitors performance remotely. Specialists are available 24/7. For Haenen, recent contact focused mainly on fine-tuning the line—adjusting sensors and belt speeds.

“If there’s an issue, they’re easy to reach. After years of weighing the options, I’m glad I made this choice. We already worked with Tolsma for storage and knew Grisnich from industrial applications where large tonnages are handled. So we were confident about capacity and quality.”

Tailored to the farm

The Optica Q can be flexibly integrated into existing sorting lines and used in various configurations. Haenen deliberately chose a combination with a mechanical size grader to keep the line compact.

“This gives me continuous visibility of all boxes and easy access with the forklift. We did consider the Optica CS, but a mechanical size grader fits this farm better. Capacity is higher, and we’ve been able to double it. An optical size grader also comes at a different price level.”

For other farms, however, a fully optical setup may be more attractive.

Two optical sorters in practice

To see such a setup, we visited Adriaan Boudeling of Poters van Piet in Swifterbant, the Netherlands, who also commissioned a new Tolsma-Grisnich sorting line this autumn.

“We had been running Schouten sorting lines for years—this was already the second one on the farm,” Boudeling explains. “They were always our number one. So when we started thinking about optical grading, choosing the Optica CS was an easy decision.”

For the quality sorter, other brands were considered, but Boudeling ultimately chose both the Optica CS and Q.

“With the potato knowledge, technology and capacity Tolsma-Grisnich has in-house, and because we prefer working with one partner for the entire line, the choice was clear.”

A clear wish list

Before construction, the farmer had an extensive wish list. The line had to be flexible, with multiple routes to the Optica Q, but without becoming a ‘maze’. The result is a clear layout with straight product flows, efficient use of space, and one person responsible for the entire process.

“That’s why we wanted a start-stop system, where the whole line stops when a box is full and automatically restarts once it’s replaced. One person can move boxes without leaving the forklift. It sounds simple, but it’s quite complex in practice.”

Together with Tolsma-Grisnich specialists, several designs were discussed.

“We went through about six different drawings, and even during construction we made some adjustments. But now that it’s running, I’m extremely satisfied. Commissioning went smoothly, and we never had downtime.”

Sorting in practice

At the time of our visit, the Optica CS was grading into five size classes, with dual outlets for the two most common sizes. The 45/55 size flows directly to the Optica Q via a buffer bunker. Other sizes are quality-sorted later, when it fits the planning or just before delivery.

Seed potatoes passing directly through the Optica Q are packed at the end of the line into big bags, sacks or boxes.

The numbers speak for themselves

Previously, from mid-October to early March, two employees worked alongside the forklift driver in the inspection room. Now only the forklift driver is needed, as manual inspection is largely eliminated.

“The calculation was quick,” says Boudeling. “With the Optica CS, we expect to deliver ten percent more seed potatoes in the correct size. The machine is more accurate than its mechanical predecessor, and fewer potatoes end up in lower-value sizes. In a year like this, every potato in the right size counts. With the Optica Q, the main gain is labour savings.”

In addition, the optical line provides valuable new data. Around 4,500 tonnes of seed potatoes per season—entirely from own propagation starting with mini tubers—pass over the line. “Knowing exactly the size and quality distribution allows us to plan our acreage much more precisely.”

Maatschap Fazembra

• Sorting line: Mechanical size grader + Optica Q
• Layout: Compact, flexible and clear
• Objective: Higher capacity with fewer labour requirements

Poters van Piet

• Sorting line: Optica CS + Optica Q
• Layout: Automatic start-stop system, straight and clear product flows, highly flexible
• Objective: More seed potatoes in the correct size, with one person managing the line

Source: Akkerbouwkrant editie december 2025