The difference is how the ribs come off. Both start as the bone-in belly: the belly with its skin and spareribs still on, cut roughly square. On a sheet ribbed belly the spareribs come off in one piece, with most of their bones and cartilage, and the belly is left relatively square. On a single ribbed belly the rib bones come out one at a time, and the meat between them stays on the belly. That meat is the intercostal meat, the lean that sits between the ribs.
What each one is called
| Sheet ribbed | Single ribbed | |
|---|---|---|
| What it is | The standard belly | Ribs pulled one by one |
| Spec | IMPS 408 skin-on, 409 skinless | NAMP 409A |
| Canada Pork code | CPI C400 | CPI C405 |
| Other names | Belly, sheet-ribbed, or just belly | Country style belly, bara (Japanese style) |
| Sizes | 4.5-5.4, 5.4-6.4, 6.4-up kg | 4.5-5.4, 5.4-6.4, 6.4-up kg |
When a buyer just says "belly", they mean sheet ribbed. Single ribbed is the one that gets named.
Bellies lighter than the smallest class, under about 9 lb (4.1 kg), usually go by skimpy bellies in the trade. USDA prints that weight in its 7-9 lb derind class.
What the single ribbed belly keeps
A sparerib is the ribs plus the intercostal meat. When the ribs come off as a sheet, that meat leaves with them and sells as a sparerib. When they come off one bone at a time, the meat stays on the belly. So a single ribbed belly carries more lean on its rib side, and it takes a cut for every rib instead of one cut for the sheet.
The spec sheet has two more points to settle for single ribbed: bevel trim, and whether the soft bones are left in or taken out. Spell both out on the order.
Who buys it
Both bellies go to the same places: fresh side pork, bacon, thin slices for shabu shabu and yakiniku. Canada Pork also lists Korean style barbecue for the single ribbed belly, and its other name, bara, is the Japanese word for belly. A buyer slicing belly for grilling, where the lean between the ribs shows on the plate, is the one who asks for single ribbed.
What it costs
Single ribbed trades at a premium to sheet ribbed. There is no published price for it: USDA prints no single ribbed line, and every belly on its daily pork report is derind or skin-on, by weight class. Get the premium quoted, and quote it per kilo or per pound over the sheet ribbed price.
Pricing it against USDA
Since USDA does not price single ribbed, price the belly underneath it. A skinless single ribbed belly is a derind belly with more lean left on, so start from USDA's derind line in the same weight class, then add the premium you were quoted. The weight classes, and why a lighter belly usually prints higher, are in the 9-13 vs 13-17 article.