I'm not a big coffee drinker and never really have been. However, I cannot resist a good cà phê sữa đá whenever I eat at our local Vietnamese restaurant. After some internet searching and a bit of trial and error, I figured out how to make this amazing drink anytime I want.
What is cà phê sữa đá? Literally, it translates to "coffee milk ice" and is a strong coffee, brewed with a drip filter into a glass containing sweetened condensed milk. This coffee can then be served hot (known as cà phê sữa nóng), or stirred together and poured over ice.
Coffee was introduced to Vietnam by the French in the late 1800s; I typically use Cafe Du Monde for my cà phê sữa đá. Cafe Du Monde is a French roast coffee containing chicory; it's readily available here in the South. Any sweetened condensed milk will do, however, I prefer the sweetness of Longevity brand, which is available in most Asian markets.
Cà phê sữa đá is brewed using a cà phê phin, which consists of a screened filter cup, a lid, and a screened plunger. I found mine at a local Asian market for about $3 and have also seen them for sale at Cost Plus/World Market. If you can't find one, I have also made cà phê sữa đá with my Aeropress with great results.
First, pour about 3/4" to 1" worth of sweetened condensed milk into a glass. The amount solely depends on how sweet you want your cà phê sữa đá, keeping in mind that the brewed coffee will be very strong.
Next, add 2 Tbsp of coffee to the cà phê phin's filter cup and screw the plunger on tightly.
Meanwhile, heat your water. I use an electric water kettle to heat my water. With any coffee, you do not want your water to be boiling; this will make the coffee bitter. Whether I am using my cà phê phin or Aeropress, I let my water come to a boil, then turn off the kettle and wait for the water to stop bubbling. The ideal water temperature for coffee is 202 degrees, or so says the internet.
Place the cà phê phin atop the glass of sweetened condensed milk. Fill the filter cup to the top with water and place the lid atop the cà phê phin.
The coffee will slowly drip into the glass; this will take around 5 minutes or longer. If the coffee is dripping too slowly, CAREFULLY loosen the plunger to allow the coffee to drip faster. This will result in a weaker brew, though.
While the coffee is brewing, fill a tall glass with ice.
Once the coffee has brewed, place the filter atop its lid to catch any last drips. Stir the hot coffee and condensed milk together. To drink hot as a cà phê sữa nóng, you're done! To drink over ice as cà phê sữa đá, pour the hot mixture over the glass of ice. Stir well and enjoy!
Don't forget to compost those used coffee grounds!