TL;DR: Vietnamese coffee is strong for two compounding reasons: robusta carries about double the caffeine of arabica, and the phin brews at a high coffee-to-water ratio. The sweetness hides it, which is the dangerous part.
Two things stack up
The bean. Robusta runs 2.2 to 2.7 percent caffeine by dry weight. Arabica runs 1.2 to 1.5. Same weight of coffee, roughly twice the hit. Vietnamese coffee is overwhelmingly robusta.
The brew. A phin drips a small amount of water slowly through a lot of coffee. It is not a long, weak filter brew. It is closer in spirit to a slow, oversized espresso, and it comes out thick.
Multiply those together and a traditional glass of cà phê sữa đá commonly sits somewhere in the region of 100 to 200mg of caffeine. That is a wide range on purpose — it depends on the roast, the grind, the ratio and how long it dripped, and anyone quoting you a precise universal figure is guessing.
Sweetness is a disguise
Bitterness is the body's usual warning that a drink is strong. Sweetened milk removes that warning entirely. A very strong coffee that tastes like a cold dessert is extremely easy to drink quickly, and then to have another one.
This is worth knowing rather than worrying about. It is a coffee. Treat it like one.
What we will and will not tell you about ours
We have not had our bottles lab-tested for caffeine, so we are not going to print a number on this page and pretend it means something. Making up a figure would be easier and we are not doing it.
What we can say: it is made from a Vietnamese robusta-led coffee powder blend, and one 300ml bottle should be treated as a normal-to-strong coffee, not a soft drink. There is sugar in it too. It is sweet coffee, and we have never been coy about that.
Questions people actually ask
How much caffeine is in Vietnamese coffee?
More than most Western coffee of the same size, because it is robusta and it is brewed strong. Robusta carries roughly double the caffeine of arabica by dry weight, and a phin brews at a high coffee-to-water ratio. A traditional small glass of cà phê sữa đá commonly lands somewhere around 100 to 200mg, though it varies enormously by stall, roast and ratio.
Is Vietnamese coffee stronger than espresso?
Per millilitre, no — espresso is far more concentrated. Per serving it is often close, because a Vietnamese iced coffee is a much bigger drink than a single shot. The sweetness also masks the strength, which is how people end up drinking two.
How much caffeine is in a Qwang Coffee bottle?
We have not had it lab-tested, so we are not going to publish a number. What we can tell you honestly: it is made from a Vietnamese robusta-led coffee powder blend, so treat one 300ml bottle as a normal-to-strong coffee rather than a soft drink.
Should I drink Vietnamese coffee in the afternoon?
That is between you and your sleep. It is a caffeinated coffee drink and it is not a small one. If caffeine late in the day affects you, this is not the drink to test that with at 6pm.
Ten bottles, $39 · Why ours tastes the way it does
Qwang Coffee, Singapore.