Sortex is the industry shorthand for optical colour-sorting — the technology that decides whether a lot of milled rice is bulk-grade or premium retail-grade. It's named after Sortex Ltd, the British company that commercialised the technology in the 1950s; today, machines from Bühler, Tomra, Anysort and others all fall under the same colloquial "sortex" banner.
How sortex works
Milled rice flows down a vibrating channel past high-speed RGB and infrared cameras. The cameras image every grain at 4,000+ frames per second. Software classifies each grain by colour, shape and surface defects, and triggers a pulse of compressed air to eject any grain outside the acceptable spec band into a reject chute.
The defect categories the cameras eject: discoloured grains (yellow tip, black spot, chalky white), broken grains beyond the specified ratio, paddy (unhusked grain), small stones, husks, and any foreign matter that survived the upstream cleaning stages.
Why two passes
A single sortex pass catches about 85–92% of defective grains, depending on the lot's starting quality. For bulk-grade rice — animal feed, ingredient supply to processed-food manufacturers — single pass is fine. For premium retail rice, single pass leaves a visible level of discoloration that consumers see in the bag and reject.
A second pass catches another 5–8% of defects. The post-pass yield is 99.5%+ pure rice with broken below 2% (for premium 1121 basmati) and foreign matter below 0.05%. The second pass is what separates retail-shelf-ready rice from generic bulk supply.
The sortex pass log
Every Vilora Impex export lot ships with a sortex pass log — a printed mill report stating the lot number, machine ID, pass count, throughput rate, defect rejection rate, and operator signature. The log is photographed at the mill and included in the documentation packet couriered to the buyer within 48 hours of sail.
Buyers always know how many passes their lot received. There's no plausible deniability — if the spec is two-pass and the log says one pass, the lot is short of spec.
Sortex spec at a glance
| Pass count | Purity % | Broken % | Foreign matter % | Typical use |
|---|
| Unsorted (post-mill) | ~95% | 5–15% | 0.2–0.5% | Animal feed, ingredient |
| Single pass | 97–98% | 3–8% | 0.1–0.2% | Bulk supply, value retail |
| Two pass | 99.5%+ | <2% | <0.05% | Premium retail, HoReCa, private label |
| Three pass (specialty) | 99.8%+ | <1% | <0.02% | Ultra-premium gift packs, export grades |
When to specify single vs two-pass
If your destination market is Gulf premium retail (UAE, Saudi Arabia, Qatar), Singapore retail, or any HoReCa biryani chain that puts the brand on the chafing dish, specify two-pass and pay the spec-match price. The cost difference is 2–4% on the per-MT FOB; the rejected-grain reduction is what justifies the premium pack price at retail.
For value-retail private label aimed at price-conscious diaspora supermarkets, single-pass is acceptable if your end customer accepts the visible discoloration ratio. Most don't, which is why two-pass is the safe default for new buyers.
Frequently asked
- Can sortex remove broken grains entirely?
- Not entirely. Sortex catches broken grains below a certain length threshold (typically 6 mm for 1121 basmati). Broken between 6–8 mm survives optical sorting because the cameras can't reliably distinguish broken from short whole grains at high throughput. Mechanical sieve-grading upstream handles those.
- Does sortex affect grain quality?
- No. Sortex is non-contact, non-thermal. Grains pass through a falling stream and are ejected with a precisely-timed air pulse. The accepted grains never touch the rejected ones — there's no mechanical damage and no temperature stress.
- How often are sortex machines calibrated?
- Premium milling partners calibrate sortex machines at the start of every lot — they run a reference sample with a known defect ratio through the machine, verify the rejection accuracy, and only then process the production lot. Calibration logs are kept by the mill operator and are available on buyer request.