---
title: "Managing the Potato Hand-Off from Washing to Grading"
url: https://www.spudmate.com/nl/potato-wet-line-drying-handoff/
description: "A potato washing line does not automatically create a suitable grading hand-off. Surface water, uneven presentation and queueing can obscure defects and…"
published: 2026-10-31
updated: 2026-10-31
author: "xtlaigc"
site: "Tianjin Goldilocks Co., Ltd."
---

# Managing the Potato Hand-Off from Washing to Grading

## Key takeaways

- Judge the hand-off at the inspection and grading points, not only at the washer exit.
- Record surface water, overlap, queueing and discharge behaviour during representative crop trials.
- Match transfer elevations and feed presentation to the selected inspection or grading duty.
- Write acceptance around samples, operating conditions and measurable process results.

## Define the hand-off problem after washing

The transfer between washing and grading determines whether the next decision can be made consistently. Potatoes may leave the washer with droplets, a surface film, pooled water at low points, released soil or groups arriving together. The important project question is therefore the condition at the inspection or grading point, not just the nominal line rate.

Manual selection needs visible product, operator access and a clear route for rejects. Mechanical grading needs potatoes to reach the rollers with a repeatable opportunity to separate by short diameter. The [water-washing and sorting solution](https://www.spudmate.com/products/potato-water-washing-sorting-solution/) can combine washing, inspection, grading, conveying and bagging, but the final arrangement and capacity remain project-specific.

[![Water-washing sorting solution with washing, inspection and conveying equipment visible for a potato process line.](https://www.spudmate.com/wp-content/uploads/2026/10/spudmate-potato-water-washing-sorting-solution-1024x512.jpg)](https://www.spudmate.com/products/potato-water-washing-sorting-solution/)

Water-washing sorting solution for the post-wash process sequence

## Observe surface water instead of assuming drying

There is no universal visual definition of a suitable post-wash condition. Observe the crop at the actual inspection or grading entrance. Note whether potatoes remain individually visible, whether they stick together, and whether water collects on the transfer surface. This establishes an operating condition for the hand-off without assuming that a separate drying machine is installed.

Check the wash exit, the first accumulation point, the manual inspection position and the grading inlet. Record the crop lot, size range, visible soil and feed condition, then repeat observations as the trial progresses. If appearance changes, note whether the cause is crop variation, queueing, transfer geometry or an operating adjustment. The [process solutions overview](https://www.spudmate.com/#solutions) provides context for the wider sequence.

- Record droplets, a surface film or pooled water.
- Check whether potatoes arrive individually or in overlapping groups.
- Mark points where water, soil or product accumulates.
- Repeat observations at the beginning, middle and end of the trial.

1. Wash and release
2. Observe surface condition
3. Present for inspection
4. Grade and sample

Conceptual workflow for evaluating the potato hand-off from washing to grading; it does not show machine layout or scale.

## Set presentation for manual selection

Manual selection depends on exposure and access. The selection platform uses chain-driven stainless rollers; friction rotates each potato through 360 degrees while workers remove bad potatoes to a central waste channel. The mechanism supports inspection, but the result also depends on loading, overlap, surface condition and the people assigned to the task.

The [potato selection platform](https://www.spudmate.com/products/potato-selection-platform/) has a stated range of 5-15 t/h and adjustable height of 960-1300 mm. These figures support an initial interface review, not a universal inspection rate. During a crop trial, increase flow in controlled steps and record items presented, defects removed, defects missed and product carried into the waste channel.

[![Potato selection platform with roller inspection surface and central waste channel visible.](https://www.spudmate.com/wp-content/uploads/2026/10/spudmate-potato-selection-platform-1024x512.jpg)](https://www.spudmate.com/products/potato-selection-platform/)

Potato selection platform for manual inspection before grading

## Protect the mechanical grading input

Mechanical grading requires a stable presentation because occupancy, overlap and settling on the rollers can change with the feed. The BF4-14 classifies potatoes by short diameter. Its roller gap and discharge direction are adjustable, each discharge belt is individually controlled, and the stainless roller bars rotate 360 degrees. These are grading-step adjustments, not substitutes for a controlled upstream hand-off.

Check the feed inlet height of 1750 mm and discharge outlet height of 1150 mm against the surrounding transfers. The stated grading range is 40-150 mm and the recorded maximum roller speed is about 560 mm/s. BF4-14 is listed at 60 t/h, but the complete line must be assessed using the selected crop, size distribution and configured arrangement.

- Confirm the transfer height against the 1750 mm feed inlet.
- Check whether the crop falls within the 40-150 mm grading range.
- Set roller gap and discharge direction before comparing results.
- Observe overlap and queueing at the grading entrance.

| Product | Verified facts | Process role | Meaning for selection |
| --- | --- | --- | --- |
| Water-washing sorting solution | Line length approximately 45 m; capacity configured to project requirements | Washing, manual selection, mechanical sorting, conveying and bagging | The overall arrangement must be configured around water supply, utilities, layout and selected component capacities. |
| Selection platform | Capacity 5-15 t/h; adjustable height 960-1300 mm; 0.8 kW; 220 V | Manual potato inspection before grading and packing | The stated range and height support an initial project review, while the trial must establish presentation and inspection performance for the crop. |
| BF4-14 | Capacity 60 t/h; grading range 40-150 mm; 4.4 kW; AC380V/50Hz | Four-level potato grading by short diameter | The grading duty and stated range guide the interface review; complete-line capacity still depends on the selected configuration. |

[![BF4-14 potato mechanical sorting machine with its grading and discharge structure visible.](https://www.spudmate.com/wp-content/uploads/2026/10/spudmate-potato-mechanical-sorting-machine-bf4-14-1024x512.jpg)](https://www.spudmate.com/products/potato-mechanical-sorting-machine-bf4-14/)

BF4-14 for mechanical potato grading by short diameter

## Choose the queue and transfer arrangement

A queue can absorb a short difference between washing and inspection, but it becomes a problem when product is compressed, hidden or repeatedly returned to the main flow. Place any accumulation where operators can observe it and where rejects remain accessible. Make the transfer direction clear so temporary accumulation is not mistaken for normal throughput.

The water-washing sorting solution has an approximate line length of 45 m, but that figure does not define usable queue length or the time available for water to leave the crop. Layout, water supply, utilities and final capacity require project confirmation. Provide the footprint, elevations, discharge direction and operator access requirements before fixing the arrangement. For related layout considerations, see the [modular potato line layout guide](https://www.spudmate.com/dry-cleaning-potato-lines-modular-layout/).

## Configure a crop trial that answers the real question

Run the route empty first to check clearances, transfer direction, access and controls. Then introduce a representative crop lot and observe the hand-off at several points. Record feed condition, approximate rate, size range, visible water, overlap, operator decisions and discharge condition. Change one material or operating variable at a time so the effect remains identifiable.

For manual selection, use agreed crop examples where available and record items presented, defects removed and defects missed. For mechanical grading, keep samples from each discharge separately identified and compare their size distribution with the project acceptance rule. State the observation period, sampling method, sample size, allowed variation and responsible recorder before the trial begins.

- Use a representative crop lot, not empty-machine observations alone.
- Record surface condition at the wash exit, inspection point and grading inlet.
- Change one setting or flow condition at a time.
- Keep samples from each discharge separately identified.

| Observation | What to record | Likely decision | Acceptance evidence |
| --- | --- | --- | --- |
| Surface water | Droplets, continuous film, pooled water and water retained at transfer points | Choose whether the current hand-off condition is suitable for the intended observation step | Timed observations at the wash exit, inspection point and grading inlet |
| Product presentation | Individual potatoes, overlap, clumps and hidden surfaces | Adjust feed condition, queue position or operating target | Representative sample showing the agreed presentation condition |
| Manual inspection | Items presented, defects removed, defects missed and waste-channel flow | Confirm staffing and operating range for the inspection duty | Recorded sample result using the agreed crop and observation period |
| Mechanical grading | Roller gap, discharge direction, sample identity and size distribution | Confirm settings and whether the selected crop is classified as required | Separate samples from each discharge compared with the project rule |
| Queue behaviour | Accumulation location, residence pattern and whether product returns to the main flow | Retain, move or resize the buffer arrangement | Repeatable flow at the agreed lower and upper operating conditions |

## Define acceptance and operating limits

Acceptance should describe the complete hand-off: crop condition, feed rate, inspection or grading duty, sample method and required result. “The line runs” is insufficient if it does not show whether potatoes were visible, rejects were removed or discharge samples met the agreed size rule. Repeat the test at the lower and upper operating conditions the project expects to use.

Do not assume a universal drying time, residual moisture value, defect-removal percentage or grading accuracy. A component rating is not the capacity of the complete line. Water supply, utilities, layout, component selection and final capacity require project confirmation. If product becomes hidden or ceases to arrive individually, the presentation condition has reached a limit that should be addressed in the arrangement or operating target.

## Prepare the project brief for a workable hand-off

Describe the crop and the decision the line must make. Include representative crop information, expected size range, post-wash condition, target flow, shift pattern, expected rejected or separated proportion, the position of manual selection and the destinations of accepted streams.

Also provide the site footprint, transfer elevations, available utilities, voltage, water supply, discharge directions, operator access requirements and proposed acceptance method. This information supports review of the washing, inspection and grading arrangement around the actual hand-off. The related [water-wash line cleaning, lifting and inspection guide](https://www.spudmate.com/water-wash-potato-line-cleaning-lifting-inspection/) covers adjacent planning duties.

## Connect the hand-off to the rest of the line

The hand-off is successful when each downstream decision receives a stable and observable feed. That may require priority for operator access at selection, matched elevations at the grading inlet or a monitored accumulation point. Surface condition, size distribution, crop loading and discharge handling all influence the result, so a capacity number alone cannot choose the arrangement.

Treat the post-wash section as a testable process boundary. Define where the crop enters, where its condition is judged, where rejects leave and where grading samples are taken. A clear boundary makes later changes easier to diagnose and gives acceptance results a practical reference. Submit the crop, layout and intended trial conditions through the [project contact page](https://www.spudmate.com/#contact).

## Review your post-wash hand-off with our engineers

Send your crop sample or representative crop information, expected size range, post-wash surface condition, target flow, shift pattern, site footprint, transfer elevations, available voltage and water supply, discharge directions, operator requirements and proposed acceptance method through the [project contact page](https://www.spudmate.com/#contact). We can review the hand-off conditions and discuss a suitable washing, inspection and grading arrangement.