What Is the Difference Between Thai Coffee and Vietnamese Coffee?

The main difference between Thai coffee and Vietnamese coffee lies in the beans, roasting, brewing method, and final flavor. Thai coffee, called oliang, is traditionally made from a blend of coffee beans and grains (like corn, soy, or sesame) roasted dark with sugar and sometimes butter. It is brewed using a cloth filter called a tungdtom, resulting in a smoky, slightly bitter, and caramel-sweet brew, usually served over ice with sweetened condensed milk or sugar syrup. Vietnamese coffee uses robusta beans roasted medium-dark, often with butter and sugar, ground and brewed through a Vietnamese phin, a small metal drip filter. It yields a strong, nutty, chocolatey coffee that is famously combined with condensed milk and served over ice as cà phê sữa đá. While both are dark, sweet iced coffees, Thai oliang has a roasted grain character and a lighter body, while Vietnamese coffee is intensely full-bodied and bold.

What Is Thai Coffee (Oliang)?

Oliang is a traditional Thai iced coffee that starts with a unique blend of coffee beans and roasted grains or seeds. Common additions include corn, soybeans, sesame, and sometimes tamarind seeds. The mixture is roasted very dark, often with sugar, which caramelizes and adds a sweet-smoky aroma. The roasted blend is ground and brewed with a cloth filter, known as a tungdtom or thung tom. This filter resembles a sock with a metal ring, and it allows fine particles to pass through, giving the coffee a slightly silty texture. The brew is strong and dark, with notes of caramel, toasted grains, and a gentle bitterness. It is typically sweetened with sugar syrup or sweetened condensed milk, then poured over ice. The result is a refreshing, smoky-sweet iced coffee that is less creamy than Vietnamese coffee and lighter in body.

To serve, vendors often pour the hot brew over a tall glass of ice and add condensed milk or sugar. Some versions include a dash of evaporated milk for extra richness. If you cannot find a cloth filter, you can use a French press or a paper filter, but the final texture will be cleaner and less rustic. A substitute for the roasted grain blend is to mix dark roast coffee with a small amount of roasted barley or chicory, which mimics the cereal notes but not the exact flavor.

What Is Vietnamese Coffee?

Vietnamese coffee is typically made with robusta beans, which have higher caffeine and a bolder, more bitter taste than arabica. The beans are often roasted with butter and sugar, giving them an oily sheen and a slightly sweet, rich aroma. The coffee is ground medium-coarse and placed in a Vietnamese phin, a small metal drip filter that sits on top of a glass. Hot water is added, and the coffee slowly drips into the glass over 4–6 minutes. This slow extraction produces a concentrated, intense brew with notes of dark chocolate, nuts, and a hint of caramel. The classic preparation is cà phê sữa đá: a layer of sweetened condensed milk at the bottom of the glass, topped with the hot drip coffee and then stirred and poured over ice. The result is a thick, creamy, sweet iced coffee with a strong coffee punch.

If you don’t have a phin, you can use a small French press or an espresso maker, but the drip filter’s slow, gravity-fed process is key to the authentic flavor and strength. The condensed milk can be adjusted to taste, but it is essential for the classic sweet and creamy profile.

Side-by-Side Comparison: Thai vs. Vietnamese Iced Coffee

How to Make Thai Iced Coffee at Home

1. Prepare the coffee blend: If you have pre-ground oliang powder, use 2–3 tablespoons per 8 oz of water. Otherwise, mix dark roast coffee with a teaspoon of roasted barley or chicory.
2. Brew with a cloth filter or French press. Place the grounds in the filter, pour hot water (just off boil), and let steep 3–4 minutes. The cloth filter should produce a deep black coffee.
3. Sweeten while hot. Add 1–2 tablespoons of sugar or sweetened condensed milk to the hot coffee and stir until dissolved.
4. Pour over ice. Fill a tall glass with ice cubes and pour the sweetened coffee over. Top with evaporated milk if desired.

How to Make Vietnamese Iced Coffee at Home

1. Add condensed milk. Put 2–3 tablespoons of sweetened condensed milk in the bottom of a heatproof glass.
2. Set up the phin. Place the phin filter over the glass. Add 2 tablespoons of Vietnamese coffee grounds to the filter, gently press the inner screen down.
3. Bloom the coffee. Pour a small amount of hot water (about 1 tablespoon) over the grounds and wait 30 seconds.
4. Fill the filter. Fill the phin with hot water (about 6–8 oz), cover, and let it drip slowly for 4–5 minutes.
5. Stir and pour over ice. Once dripping finishes, stir the coffee and condensed milk together, then pour over a glass full of ice.

Key Ingredients and Tools to Recognize

Condensed milk: Thick, sweet, shelf-stable milk with sugar added. It provides creaminess and sweetness without diluting the coffee. In both Thai and Vietnamese iced coffee, it creates a luscious texture and balances strong coffee. Its caramel-like sweetness is a defining flavor.

Cloth coffee filter (tungdtom): A reusable cloth bag with a metal ring handle, used in Thai coffee stalls. It allows fine grounds and oils to pass, giving a fuller body and slightly earthy taste. It must be rinsed and stored in water to prevent mold.

Vietnamese phin: A small stainless steel or aluminum dripper with a perforated base, a press screen, and a lid. It sits directly on the cup and uses gravity to slowly extract a strong brew. The four-minute drip creates a concentrated, aromatic coffee.

Oliang powder: Pre-blended Thai coffee mix that includes roasted grains and sometimes sugar. It is dark and smells of burnt caramel and toasted corn. It dissolves slightly, so the final cup may have fine sediment.

Iced coffee: The common denominator: both coffees are designed to be served cold, often over a full glass of ice, which locks in the sweet, strong flavors and makes them refreshing in hot climates.