The grade bands most often used for Egyptian export to Europe are roughly:
A widely used set of bands runs S 150–300 g, M 300–450 g, L1 and L 450–600 g, and L2 and XL above 600 g. But another convention in common use starts lower — S at 50–150 g, M at 150–300 g, L1 at 300–450 g, L2 at 450–600 g and XL at 600–800 g. Both are legitimate. They are simply different packhouse conventions, and a carton printed to one of them will not match a contract written to the other.
If you order "M" expecting 300–450 g and receive 150–300 g, every tuber in the container is roughly half the weight you priced. The consignment is not defective — it simply was not graded to your understanding of the letter. This is one of the most common and most avoidable disputes in the trade, and it is almost always resolved in favour of whatever is written in the contract.
The fix is one line. Write the grade as a gram range: "M = 300–450 g per tuber" rather than "Size M". Put the same numbers on the purchase order, the specification sheet and the pallet tag, and ask for the packing list to state the range rather than the letter.
A crop does not come out of the ground in one size. A supplier who promises 100% of a single grade is either going to fail, or is going to buy in from elsewhere to fill the container. Specify a mix as percentages with a tolerance, for example 40% L1, 40% L, 20% M with ±5% per grade, and state what happens if the mix cannot be met — accept, discount or reject.
Retail programmes usually pull M and L1. Food service takes L and XL. Processors care about dry matter and total weight rather than grade, and will often take the off-size the retail programme rejected, which is why a packhouse running several outlets can hold a better price for you than one running a single line.
Agree the allowance for tubers outside the band, and separately for damage and defects, per carton rather than per consignment. A container-level tolerance lets a supplier average out a bad pallet; a carton-level tolerance does not. Agree the rejection threshold in the same clause so there is no argument about remedy after arrival.
Grade bands describe a range, and a carton can technically meet the specification while looking inconsistent if it holds tubers from both ends of the band. For retail packs, add a uniformity clause — that tubers within a carton should be visually consistent in size and shape — because that is what the shelf actually judges.
