Pattani budu: 9-15 months of fermenting, 18-29% salt, different in every bottle
Budu is salt-fermented anchovy from Thailand's far south. Pattani research gives ratios, time and saltiness; a Malaysian study found microbes differ by bottle.
- Budu is made from anchovies and salt. Pattani producers use 2:1 to 3:1 fish to salt and ferment it for 9-15 months.
- Pure budu measured in research was 18-29% salt by weight. Use a little and taste first.
- Budu varies widely by source and by bottle, in salt, protein and microbes. A Malaysian study found bottles of the same brand differed.
- Budu is made from fish. People with a fish allergy must avoid it, and should always ask, because khao yam is often dressed with budu.
Budu (บูดู) is the salt-fermented fish sauce of Thailand’s far south: anchovies and salt, fermented for the better part of a year or longer, then poured over khao yam rice salad or used in cooking. A Yala Rajabhat University survey of producers in Pattani found budu fermented for 9-15 months, with pure budu at 18-29% salt. A Malaysian study that looked at the bacteria inside bottles of budu found that no two bottles were alike. This article covers how budu is made, what the numbers say and how to use it.
What budu is made from
The study “Budu Production in Pattani” (Journal of Yala Rajabhat University, 2009) surveyed producers and found:
- Most producers still used the traditional method.
- Anchovies (pla katak, called “Katak fish” in the paper) and salt at 2:1 to 3:1 fish to salt by weight.
- Fermentation for 9-15 months, then bottling as “pure budu”.
- The leftover solids, with added salt and other seasonings, became “seasoned budu”.
- Pure budu had a water activity of 0.73-0.85 and was 18-29% salt.
- It was sold mainly in Pattani, Yala and Narathiwat.
A Malaysian study of budu from Kelantan gives close but different figures: anchovies in a 21.5-25.7% brine, fermented in earthen jars for 6-12 months. The same paper’s abstract says 6 to 18 months, so we give both.
Worked example: working out the salt, step by step
Say you start with 30 kg of anchovies.
- At 3:1, you use 30 ÷ 3 = 10 kg of salt, 40 kg in total. Salt is 10 ÷ 40 = 25% of the mix.
- At 2:1, you use 30 ÷ 2 = 15 kg of salt, 45 kg in total. Salt is 15 ÷ 45 ≈ 33%.
- Fermenting for 9-15 months means about 270-450 days before the first bottle.
- Pure budu measured at 18-29% salt means 10 g of budu holds about 1.8-2.9 g of salt.
That last line is why budu is used sparingly, and why you taste before adding more. If you watch your sodium, see ordering lighter on salt and sugar.
No two sources are alike
A second Yala Rajabhat University study from the same year compared bottled budu from producers in Pattani and Narathiwat, sorted into two classes of producer, because recipes and methods differ from place to place.
| Measure | Class 1 | Class 2 |
|---|---|---|
| Water activity (aw) | 0.72-0.73 | 0.73-0.91 |
| Protein | 7.17-12.08% | 2.96-9.28% |
| Salt | 25.81-30.34% | 12.07-26.53% |
| Lactic acid | 0.10-0.14% | 0.03-0.09% |
| Total microbes (colonies per gram) | 3.0×10³ to 3.2×10⁴ | 9.0×10³ to 1.5×10⁸ |
Class 1 scored significantly higher in tasting. The study also found adulterants in one Class 1 sample and seven Class 2 samples. The production survey found that most producers were not certified by any agency, and on a checklist adapted from Thai Food and Drug Administration criteria, every producer fell short on all six points. Both studies date from 2009; things may well have changed since.
These numbers say “budu” is not one standard product. Saltiness can differ by almost double from bottle to bottle. Taste before you use it whenever you change source.
Microbes that differ by bottle
A study in PeerJ (2021) bought 20 bottles of budu from 7 brands in Kelantan, Malaysia, and sequenced the bacterial DNA when the bottles were opened and again after 3 and 7 months, 60 samples in all.
- The most common genus was Tetragenococcus, a salt-loving bacterium, averaging 38.77% of the bacteria and reaching 98.62% in some bottles, yet nearly absent in others.
- Some bottles were dominated by Halanaerobium instead, at up to 58.15%.
- Even bottles of the same brand differed. The authors put this down to uncontrolled production from batch to batch.
- Seven months after opening, some groups of bacteria rose in certain brands. The study did not test whether this was harmful; it only shows that what is in the bottle can change.
The study did not measure histamine, but it cites earlier work that found histamine above 50 mg per 100 g in budu from 7 of 12 producers. That is Malaysian budu and cannot stand in directly for Thai budu. If you have reacted badly to fermented fish before, talk to a doctor.
What budu goes with
The best-known dish is southern khao yam: rice tossed with many fresh herbs and vegetables and dressed with budu. Some provinces use a curry broth or shrimp paste instead. Southern Muslim food is covered in eating halal in Thailand, and the South’s bold flavours in southern curries.
Common mistakes
- Pouring budu like fish sauce without tasting. Some bottles are close to 30% salt. Add a little at a time.
- Assuming every bottle is the same. Thai and Malaysian research both found big differences in salt, protein and microbes.
- Forgetting budu is fish. With a fish allergy, ask every time. See food allergies and Thai food.
- Leaving an opened bottle for ages without checking. If the smell, colour or look changes from when it was new, do not take the chance.
- Judging Thai budu by Malaysian results. Recipes and producers differ. The Malaysian work is useful background, not a stand-in.
Summary
Pattani budu is made from anchovies and salt at 2:1 to 3:1, fermented for 9-15 months. Pure budu is 18-29% salt, and sources differ widely. A Malaysian study also found that the microbes in each bottle differ, even within one brand. Use budu sparingly, taste before adding more, and if you are allergic to fish, ask every time you order khao yam.
Sources
FAQ
How is budu different from fish sauce (nam pla)?
Both are salt-fermented fish. Budu is the seasoning of Thailand's far south and the Malaysian side of the border, made from anchovies fermented for many months, and sold both as pure budu bottled after fermentation and as seasoned budu made from the leftover solids. The studies we read did not measure it against fish sauce, so we will not say which is saltier.
What is the difference between pure and seasoned budu?
The Pattani study explains that the liquid bottled after fermentation is pure budu, and the leftover solids, with added salt and other seasonings, become seasoned budu. They are different products; check the label or ask the seller.
I am allergic to fish. Can I eat khao yam?
It is risky, because khao yam is often dressed with budu; some places use a curry broth or shrimp paste instead. Ask every time, and with a severe allergy, talk to your doctor before eating out.
Ingredients and heat vary by kitchen and recipe. If you have a food allergy, ask before you order, every time.