Thai script ต้มแซ่บ. No standard defines it — the register returns zero for ต้มแซ่บ and แซ่บ alike. What exists is TCPS 1543/2563, a 2020 standard for liquid, ready-to-cook tom yum, and TCPS 495/2547, a 2004 standard for the dried version. The liquid standard's own definition never mentions chilli — heat only arrives through an optional roasted-chilli paste — while the older dried standard lists chilli directly among its core herbs. Neither standard currently has a single certified producer.
Searching for the Isan dish returns nothing
We queried the Thai Industrial Standards Institute's public register of Thai Community Product Standards directly on 10 September 2026 for ต้มแซ่บ and แซ่บ. Both return zero results. A control search for ขนมจีน, run in the same session, correctly returns six standards, confirming the search mechanism itself is working. An earlier content-gaps run reached the identical result on 8 September 2026, trying the same terms independently.
Nothing official names the pork ribs or bones, the galangal-heavy broth, or the sour, herbaceous balance that makes tom saap recognisably an Isan dish rather than a central Thai one.
What Thailand standardized instead: tom yum, twice, and differently
Searching ต้มยำ returns exactly two standards, sixteen years apart, and reading them side by side turns up a genuine disagreement rather than a simple update.
| TCPS 1543/2563 (2020) — liquid, น้ำต้มยำ | The requirement |
|---|---|
| Form | Liquid, ready to cook or reheat |
| Base herbs | Galangal, lemongrass, kaffir lime leaf - pounded or ground in water |
| Chilli in the base definition | No - only via optional nam prik pao (roasted chilli paste) |
| Protein | Optional - fish or shrimp, boiled and ground or left in pieces |
| Dairy/coconut | Optional - coconut milk, evaporated milk or condensed milk |
| Seasoning | Lime juice, tamarind water, sugar, fish sauce, salt |
| Quality rule | Must not contain lime seeds or chilli stalks |
| Acidity ceiling | pH not more than 4.6 |
| Permitted names | “Instant tom yum liquid” or “ready-to-cook tom yum” |
| TCPS 495/2547 (2004) — dried, เครื่องต้มยำ | The requirement |
|---|---|
| Form | Dried, cut large or ground to powder |
| Base herbs | Galangal, lemongrass, kaffir lime leaf, chilli - all named directly |
| Chilli in the base definition | Yes - listed alongside the herbs, not an optional add-on |
| Seasoning | Sugar, fish sauce, salt, lime |
| Moisture ceiling | Not more than 13% by weight |
| Aflatoxin ceiling | Not more than 20 micrograms per kilogram |
| Total plate count | Not more than 500,000 colonies per gram |
The finding worth carrying: the newer, liquid standard's definition clause builds tom yum from galangal, lemongrass and kaffir lime leaf, with chilli entering only if the optional nam prik pao, roasted chilli paste, is added. The older, dried standard puts chilli directly in its list of core herbs, alongside galangal and lemongrass, with no optional language around it. On paper, Thailand's own standards disagree about whether tom yum is fundamentally spicy.
One product, not two. TCPS 1543/2563 treats coconut milk, evaporated milk and condensed milk as an optional addition inside a single definition. Thailand's own paperwork does not distinguish creamy tom yum (nam khon) from clear tom yum (nam sai) as separate products — both are the same standard, with or without dairy.
One more connection worth noting: TCPS 1543/2563 and the gaeng som liquid standard, TCPS 855/2563, were announced by the Thai Industrial Standards Institute on the same date, 3 July 2020, under the same signature. Thailand's two central Thai sour soups were standardized as a pair.
Neither standard has a single current producer
We queried the certificate register — a separate government database of who currently holds a valid certificate against each standard — directly on 10 September 2026, against both TCPS 1543/2563 and TCPS 495/2547. Both return zero current holders.
That is a genuine contrast with the curry-paste standards covered on our massaman page, where two general standards currently carry eighteen active certificates between them. Sour-soup bases, liquid or dried, central Thai or otherwise, appear to be a category the country's registered community producers currently don't bother certifying at all — which makes the standards a paper definition of what tom yum legally is, without a single traceable factory behind either version.
What we could not confirm, and did not invent
- The dish itself. No standard names tom saap, its pork ribs or bones, or the Isan-style balance of sour and herbaceous flavour that distinguishes it from central Thai tom yum.
- Proportions. Neither tom yum standard gives a quantity or a ratio - both name ingredients, not a recipe.
- The word แซ่บ itself. Whether it carries any separate entry in the Royal Institute's Thai dictionary was not checked this run.
- The jaew and roasted-rice-powder standards. TCPS 1370/2556, jaew dipping sauce, and TCPS 1381/2562, roasted rice powder, are genuine parts of the same northeastern seasoning family and already covered on our larb page, but neither defines tom saap itself, so neither is stretched over this page.
- Prices and restaurants. No official source for either, so none are given.
Frequently asked questions
No. We searched the Thai Industrial Standards Institute's public register on 10 September 2026 for ต้มแซ่บ and แซ่บ, and both return zero standards. An earlier run on 8 September 2026 found the same thing independently. A control search for ขนมจีน, run in the same session, correctly returns six standards, so the negative is a real absence rather than a broken search.
Tom yum - the central Thai sour soup - and it has standardized it twice. TCPS 1543/2563 defines a liquid, ready-to-cook version: galangal, lemongrass and kaffir lime leaf pounded in water, with fish or shrimp, lime, tamarind, sugar, fish sauce and salt, plus optional coconut milk or milk. TCPS 495/2547, sixteen years older, defines a dried, powdered version with a shorter, more direct ingredient list. Tom saap, the Isan dish most people mean when they say the name that sounds closest to “saap,” has no standard of its own in either form.
It depends which of the two standards you read, and the difference is real, not a simplification. The 2020 liquid standard, TCPS 1543/2563, never names chilli in its core definition - the base is galangal, lemongrass and kaffir lime leaf, and heat only enters if the optional nam prik pao, roasted chilli paste, is added. The 2004 dried standard, TCPS 495/2547, lists chilli directly alongside the other herbs in its own definition clause. Read together, Thailand's paper trail on tom yum has moved from treating chilli as essential to treating it as optional, at least in what a factory-made liquid base is required to contain.
No - and this is worth knowing if you assumed otherwise. TCPS 1543/2563 makes coconut milk, evaporated milk or condensed milk an optional addition within a single definition, not a separate product category. In Thai community-product-standard law there is one tom yum liquid standard, and whether it ends up creamy or clear is a recipe choice within it, not a difference the standard itself tracks.
Nowhere, currently. We queried the certificate register - a separate government database from the standards themselves - against both TCPS 1543/2563 and TCPS 495/2547 on 10 September 2026, and both return zero current certificate holders. Compare that with the general curry-paste standards covered on our massaman page, which have eighteen active certificates between them: sour-soup bases appear to be a category the country's community producers currently don't bother certifying at all, whichever version you mean.
Nothing official - this is popular and culinary usage, not a government definition, and we're flagging it as such rather than presenting it as verified. Tom saap is commonly described as Isan's version of the same idea: pork ribs or bones rather than the central Thai fish or shrimp, no coconut milk, and a more herbaceous, sour-forward balance. None of that comes from a Thai standard, because no Thai standard names the Isan dish at all.
Related guides
- Gaeng som — the central Thai sour curry standardized the same day as tom yum's liquid standard.
- Massaman curry — the curry with no standard at all, next to two generic ones that eighteen real producers actually use.
- Larb — the Isan salad, and the parasite-safety standard read straight into it.
- Khao soi — the northern noodle bowl, and the curry powder written into its standard.
- Thai regional food — how the four regional kitchens differ.
- Thai street food — how ordering actually works.
Eating this well for this little is part of the arithmetic
If the food is what started this, the next question is what a month in Isan or Bangkok actually costs.
Sources & References
- Thai Industrial Standards Institute, Ministry of Industry - the public register of published Thai Community Product Standards, queried directly on 10 September 2026 against ต้มแซ่บ and แซ่บ. Both searches return zero standards. A control search for ขนมจีน on the same register, in the same session, correctly returns six standards, confirming the search mechanism works. An earlier run on 8 September 2026 reached the same result independently
- Thai Community Product Standard TCPS 1543/2563, Tom Yum Soup (Nam Tom Yam). Its definition clause 2.1 describes galangal, lemongrass and kaffir lime leaf, washed, pounded or ground, dissolved in water, to which fish or shrimp, boiled and ground or left in pieces, may optionally be added; seasoned with lime juice, tamarind water, sugar, fish sauce, salt and roasted-chilli paste (nam prik pao); coconut milk, evaporated milk or condensed milk may optionally be added; boiled, hot-filled, reheated with its container, and cooled immediately. Clause 3.1 requires the product not to contain lime seeds or chilli stalks, and clause 3.6 sets a pH ceiling of 4.6
- Thai Community Product Standard TCPS 495/2547, Tom Yum Paste (Khrueang Tom Yam), the dried version. Its definition clause 2.1 describes herbs used for making tom yum such as galangal, lemongrass, kaffir lime leaf and chilli, washed clean, optionally cut into large pieces before being dried or ground to a powder, then seasoned with seasonings such as sugar, fish sauce, salt and lime, and dried - naming chilli directly in the base definition, unlike the later liquid standard
- Thai Industrial Standards Institute - the public register of certified community producers, queried directly on 10 September 2026 against both tom yum standards, TCPS 1543/2563 and TCPS 495/2547. Both return zero current certificate holders
Primary and official sources are cited above. Government rules, fees and procedures in Thailand change over time and vary by office; always confirm current requirements with the relevant authority before relying on them. BAANLYY never takes paid placement in editorial content.
