Thai vs Vietnamese Coffee: What Differs

The short answer

Thai and Vietnamese iced coffee arrive looking like siblings. Both are dark robusta, both are sweet, both are poured over a glass of ice, and both get their dairy out of a tin rather than a fridge. Past that, almost nothing matches.

The Thai drink is brewed by steeping. Grounds go into a cotton bag filter shaped like a wind sock, boiling water goes over them, and the brew is poured back through the cloth. The Vietnamese drink is brewed by dripping: a metal phin sits on the glass and gravity takes four to six minutes to push 100 ml of water through 20 g of coffee.

The powder is different too. Traditional Thai coffee is not all coffee; the blend carries corn, brown rice, sesame, soybeans and brown sugar. And the milk is different in a way that changes the whole structure of the glass: the Thai version is topped with evaporated milk, which is not sweetened, where cà phê sữa đá (Vietnamese iced coffee with condensed milk) sits on condensed milk, which is.

Side by side

	Kafae boran / kafae thung	Cà phê sữa đá
Brew method	Steeped, then poured through cloth	Gravity drip through a metal filter
Filter	Cotton bag, “sock filter”	Phin: perforated metal, no paper
Species	Dark-roasted robusta	Dark-roasted robusta
What else is in the powder	Corn, brown rice, sesame, soybeans, brown sugar; also salt, butter, tamarind seeds	Nothing added to the grounds, though butter or sugar may go in at the roast
Dose and water	Not standardised in the sources found	20 g to 100 ml, about 1:5
Dairy	Evaporated milk on top, condensed milk optional	Sweetened condensed milk, in the glass first
Fresh milk	No	No
Reported body	“A very light body”	Thick, close to syrupy before the milk
Caffeine per serving	No published measurement found	ESTIMATE 320–490 mg

The Thai column is thinner than the Vietnamese one because the published record is thinner. The phin has a standard dose because the device has a standard size; a cloth filter does not, and nothing we read gives a dose or a ratio for it.

The filter: cloth against metal

Saveur’s Austin Bush describes the traditional Thai method as a cloth filter that resembles a wind sock, and gives it both of its names: kafae thung, “bag coffee”, and kafae boran, “old-fashioned coffee”. Grounds are moistened in the cloth, steeped, agitated, and the liquid is poured through. Perfect Daily Grind describes the same thing as a cotton bag or sock filter steeped in boiling water.

Steeping and dripping do different things to the same grounds. A steep puts all the water in contact with all the coffee at once and then strains it. A phin wets the bed, lets it swell against a press plate, and then lets 100 ml find its way through under nothing but its own weight. The phin’s three levers are grind, dose and how far down the press is screwed, which is covered on how to use a phin.

Cloth also behaves differently from metal. It holds oils and fines back in a way perforated metal does not, which fits the light body Bush reports. No measurement comparing the two filters was found, so that is a plausible mechanism rather than a demonstrated one.

The blend: Thai coffee powder is not all coffee

This is the difference that matters most in the cup.

Perfect Daily Grind reports that traditional Thai coffee contains dark-roasted robusta with brown sugar, corn, brown rice, sesame and soy beans, and lists salt, butter and tamarind seeds as further additions. The reason given is economic: grains and seeds stretched a scarce and expensive supply when the drink developed during the Second World War, and the flavour that resulted became the flavour people wanted.

Vietnam has a version of the same history, worked through on what ends up in the bag: butter, oil, sugar or caramel at or after the roast, with soybean, corn or chicory as filler at the cheap end. The difference is where the addition sits. In Vietnam it is a property of some bags and the ingredients list tells you which. In traditional Thai coffee the blend is the drink, and a packet of Thai coffee powder is sold as a blend rather than as coffee that has had things done to it.

In both countries the addition is declared, and in both it is what the drink is supposed to taste like.

The milk: which tin, and when it goes in

Sweetened condensed milk and evaporated milk come out of similar tins and are not the same product. US food regulation defines the difference. Sweetened condensed milk is water partly removed from a mixture of milk and nutritive carbohydrate sweeteners, at a minimum 8% milkfat and 28% total milk solids, with enough sweetener used to prevent spoilage. Evaporated milk is water partly removed from milk only, at a minimum 6.5% milkfat and 23% total milk solids, and no sweetener appears in its definition at all.

So the two drinks sweeten themselves by different routes:

• Thai. Evaporated milk is drizzled on top, adding dairy and fat but no sugar. Sugar comes from the brown sugar in the blend, from sugar added to the brew, or from condensed milk where it is used, which Bush’s version treats as optional.
• Vietnamese. Condensed milk goes into the glass before brewing, the hot coffee drips onto it and dissolves it, and it supplies all the dairy and all the sweetness at once. There is no fresh milk and no evaporated milk in it.

That sequencing is not decoration. It is why a cà phê sữa đá needs a 1:5 brew in the first place: the coffee has to survive a pour of near-syrup and then a full glass of melting ice. The condensed milk page works through the figures.

Which one is stronger

No published measurement settles it.

What can be said points one way. Both drinks use robusta, which was measured at a mean 2.9% caffeine by dry weight against arabica’s 1.8%, so the species gives neither an advantage. The phin brews pure coffee at about 1:5, and our arithmetic for a 20 g dose comes out at an estimated 320–490 mg of caffeine, against the 113–247 mg the FDA gives for a 12 fl oz cup of brewed coffee; the working and every assumption in it are set out separately. Traditional Thai powder is cut with grain, so a gram of it holds less coffee than a gram of Vietnamese grounds, and no dose or ratio for the cloth filter appears in the sources we read.

Against that, Bush describes the Thai cup as having plenty of caffeine, and a steep extracts efficiently. Both statements are qualitative. Until someone measures a kafae thung brew, the comparison rests on the ratio and the blend, which is a weaker footing than a number.

Two countries, two crops

The scale behind the two drinks differs more than the drinks do. For the 2026/27 marketing year, which runs October to September, the USDA forecasts Vietnam at 32.5 million 60 kg bags, 31.4 million of them robusta and 1.1 million arabica, out of a world total of 189.7 million. Vietnam is second only to Brazil. Thailand is forecast at 900,000 bags, all on the robusta line, which puts it 19th among the countries the circular lists individually and is about one thirty-sixth of Vietnam’s crop.

The species picture is less lopsided than those numbers suggest. Vietnam’s crop is roughly 97% robusta, for reasons of altitude that robusta goes into. Thailand grows mostly robusta too, but Perfect Daily Grind reports a recent shift towards arabica, with most of the country’s high-quality arabica coming from Chiang Mai and Chiang Rai in the north and Chumphon and Surat Thani in the south also contributing significant volumes. The same publication calls Thailand the world’s 20th-largest producer, down from the top 15 a decade ago, and notes that most of its specialty-grade coffee stays inside the country.

The USDA circular gives Thailand no arabica figure. That is a reporting threshold rather than a statement that the country grows none.

What the two drinks share

Strip out the filter, the blend and the tin, and the same problem is being solved twice. Both traditions start from robusta, which is the species each country mostly grows. Both roast it dark; Saveur calls the Thai result distinctly burnt. Both take their dairy from a tin rather than a bottle.

And both are served cold. Bush notes that iced coffee is close to standard in Thailand’s heat, which is equally true of the glass of cà phê sữa đá on a pavement table in Saigon.

Two countries working under similar constraints landed on similar answers and then diverged on the details. The details are the drink.