Prime ribs for bak kut teh. Big marrow bones for ABC soup. Spine, or soft bone if your family likes chew, for lotus root soup. That is the short answer. The long answer is about what each bone carries into the pot: meat, fat and body, and which of the three your soup actually needs.
The usual problem. The freezer label says pork bone and little else, so one bag gets bought for every soup in the rotation. Then the bak kut teh comes out thin, and the ABC turns greasy enough to leave a slick. Different soups pull different things from a bone. Pick the bone for the soup, not the label.
What a bone gives your soup
Every pork bone hands the pot some mix of three things. Meat, the part you eat straight off the bone. Fat, which carries flavour but can tip a light soup into heavy. And body, the silky weight that collagen and marrow release over a long simmer.
No bone is best at all three. Prime ribs are mostly meat. Big leg bones are mostly body. Spine and soft bone sit in between. That is the whole trick: name what your soup needs, then buy the bone that carries it.
Bak kut teh: prime ribs
Bak kut teh is an eating soup. The ribs are the dish and the peppery broth is there to carry them, so the bone that matters is the one with the most meat on it. Prime ribs, the long ribs with a thick band of meat along the bone, turn tender in about an hour and stay juicy when the pot goes back on the stove for refills.
If you like the springy crunch of cartilage, add a few soft bone ribs on top. What you should keep out of a light, peppery pot is the big marrow bone. Its fat clouds the broth and pulls the soup toward heavy when this style wants clean.
ABC soup: big marrow bones
ABC soup gets its sweetness from the vegetables. Potato, carrot, onion, corn and tomato do the flavour work, and the pork’s job is depth underneath them. Big leg bones do that job best. The marrow and collagen inside give the broth weight and a rounder taste, and the bones cost less per kilo than any meaty cut.
Meat is optional here. Add a handful of prime ribs if the family wants something to chew in the bowl, but the base works on big bones alone. Give the pot at least two hours and skim in the first twenty minutes.
Lotus root soup: spine or soft bone
Lotus root soup sits in the middle. You want some meat in the bowl and a broth with real body, because lotus root brings a clean, starchy sweetness and no richness of its own. Spine bones, often sold as dragon bone, carry pockets of meat plus plenty of collagen. Soft bone ribs do a similar job with more chew. Either one holds up to a two hour simmer without turning the soup greasy.
Peanuts, dried cuttlefish or red dates all sit well with either bone. The broth should end up light brown, sweet and just slippery on the lips. If it coats the spoon like gravy, there was too much marrow bone in the pot.
The bones, side by side
| Prime ribs | Big marrow bones | Spine and soft bone | |
|---|---|---|---|
| Meat to eat | Plenty | Almost none | Some |
| Fat | Moderate | High, mostly marrow | Low to moderate |
| Body it gives | Light | Heavy | Medium and silky |
| Time to tender | About 1 hour | 2 to 3 hours | About 2 hours |
| Best soup | Bak kut teh | ABC soup | Lotus root soup |
One rule ties the table together: the longer the simmer, the less the meat matters and the more the inside of the bone does the work. Ribs shine inside an hour. Big bones only pay off past the second hour, so match the bone to the time you have, not just the soup.
Buying and prep notes
- Buy bones already sawn into sections. Cut faces release marrow and collagen far faster than a whole length of bone.
- A 1kg bag suits a family pot of four to six bowls. Two soups in one week means two bags, not one bag stretched thin.
- Blanch first, whatever the soup. Cover the bones with cold water, boil hard for five minutes, pour everything off and rinse. The grey scum you dump is the difference between cloudy and clear.
- Mix on purpose, not by accident. Prime ribs plus one big bone gives an eating soup with extra body. A random handful of everything gives a soup that tastes like nothing in particular.
Before it hits the pot
Thaw the bones fully in the chiller, not on the counter. SFA says frozen food should not be left to thaw at room temperature, and puts the chiller range at 0°C to 4°C.1 Poke the bag with a skewer and check for ice crystals before the bones go in. Fully thawed bones come up to a boil faster and blanch cleaner.2
Buy the bone the soup asked for
Prime ribs, big bones, spine and soft bone, sawn for the pot and bagged by the kilo.
- Singapore Food Agency, Guidelines on Thawing of Food (updated 27 Sep 2024): “Frozen food should therefore not be left to thaw at room temperature, to prevent food poisoning bacteria that may be present from multiplying to high levels. Frozen food is recommended to be thawed in the chiller maintained at a temperature not below 0ºC and not above 4ºC, or by using a microwave oven.” The same document adds: “Check for ice crystals in the food using your hand or a skewer”, and “Cook thawed meat immediately and do not refreeze thawed food.” sfa.gov.sg ↩︎
- The bones this guide matches to each soup, sawn and bagged for the pot: our pork bone selection. ↩︎