Not all onions are the same size. Some are small, some are medium, some are large. And when they're mixed together, buyers price the whole load to the lowest grade. Here's how a screen sizer turns a mixed harvest into consistent grades—each sold at its own price.
The Problem with Mixed Sizes
Onions come in all sizes. A single field produces small, medium, and large onions all mixed together. When they're sold as-is, buyers discount the entire load to the lowest grade.
For packers, this means lost revenue. The large onions that should command a premium price end up subsidizing the smaller ones. Sorting by size isn't just about appearance—it's about capturing the full value of your harvest.
But not all graders are created equal. Roller graders work for round onions. Drum graders work for flat ones. For round yellow and white onions that need precise sizing, there's a better option: the screen sizer.
How a Screen Sizer Works
A screen sizer uses a series of screens with holes of different sizes. Onions travel across the screens—smaller ones fall through the smaller holes first, medium ones through the next, and the largest continue to the end. Each size collects in its own outlet.
The Fstsort screen sizer is designed for packers who need high precision and high volume:
Feature | What It Means for Your Operation |
|---|---|
15–20 tons per hour | Enough throughput for commercial packing lines—keeps up with peak harvest |
4–5 adjustable grades | Sort onions into multiple size grades—sell each grade to the right market |
Customizable screen holes | You measure your onions; we build the screens to match your exact diameter requirements |
10 polishing brushes | Removes dirt and loose skins before grading—cleaner onions, more accurate sizing |
The system integrates pre-sorting, brush cleaning, manual inspection, and grading into one continuous flow. Pre-sorting removes the smallest onions early, making the overall sorting process more efficient and improving final consistency.
The Advantage of Customizable Screens
One machine. Multiple markets. That's the real value of a screen sizer.
Different buyers want different sizes. A supermarket in one country might want medium onions. A food processor might want small ones. An export buyer might want large ones.
With a screen sizer, you don't need a different machine for each market. You just change the screens. A single machine adapts to different size requirements—reducing equipment costs and increasing flexibility.
What this means for your business:
Benefit | Why It Matters |
|---|---|
One machine, multiple markets | Change screen sizes to match different buyer specifications—no need for multiple graders |
Low maintenance | Screens are easy to replace—reduces downtime and maintenance costs |
Durable construction | PVC and durable materials minimize damage to onions—product stays intact |
Simple operation | Optimized for easy operation—workers get up to speed quickly |
From Field to Pack: A Complete Line
The screen sizer is part of a complete onion sorting line:
1. Elevator — Feeds onions into the system at a controlled rate
2. Pre-sorter — Removes the smallest onions early for better efficiency
3. Brush cleaning — Polishing brushes remove dirt and loose skins
4. Manual inspection table — Workers spot and remove defective onions
5. Screen sizer — Sorts by diameter with multiple adjustable grades
6. Gravity conveyor — Moves graded onions to packing
Each component can be added or removed depending on your needs. Start with the sizer, add cleaning later. Or build the full line from day one.
Fstsort has already delivered onion grading solutions to customers in Senegal, Turkey, and the United States—helping packers in diverse markets turn mixed harvests into premium-grade products.
Learn more on our onion sorting grading machine page →
Size Matters. The Right Grader Makes It Count.
Onions come in all sizes. The right grader makes sure every size finds its right buyer—at the right price. A screen sizer gives you the precision, capacity, and flexibility to turn a mixed harvest into multiple revenue streams.