Condensed milk–called sữa in Vietnamese, and largely the only kind of milk available there–is a simple thing. It's exactly what it sounds like: milk that's been reduced to 40% of its original volume, then mixed with a lot of sugar and cooled.
It's indispensable in the making of cà phê sữa đá, the coffee drink that (with no offense intended to the Rockstar-drinking bros of Huntington Beach) ought to be named the official caffeinated drink of Orange County. We make a lot of it around here, because it packs a caffeinated, sugar-laden punch that wakes us up a lot more efficiently than 7-Eleven Standard.
So why is it so damn hard to find condensed milk without additives?
While I was at 99 Ranch the other day, I needed more sweetened condensed milk–we make cà phê sữa đá in a pitcher and keep it in the fridge for easy, if less authentic, access–and was presented with more than a dozen brands, most of which I'd never heard of.
As is my wont, I started reading labels. There were cheap brands that cost just a dollar or so a can, but the ingredients lists were not encouraging–whey powder, various chemicals, artificial coloring (who cares what color condensed milk is?).
It turned out that the only two brands that contained just milk and sugar were good ol' Eagle Brand (the Borden brand that was the first sweetened condensed milk ever made), Longevity brand, and Nestlé's equivalent, La Lechera, all of which were double the price. It's worth it for the good stuff that won't separate in the hot coffee.
In the meantime, in case you don't already know how to make it, here's the recipe for a single serving Vietnamese iced coffee. You do need a Vietnamese coffee filter (called a phin) for this, but they're available for just two or three dollars at any Asian market. If you want it hot, just skip step #8 and call it cà phê sữa nóng instead.
2-3 tablespoons condensed milk
2-3 tablespoons coffee (Trung Nguyen is traditional, but I use Portola coffee, ground coarsely)
1. Pour the condensed milk into a small coffee cup and set the phin on top.
2. Take out the screw-top filter insert and put the coffee in the bottom.
3. Screw the filter top on relatively tightly.
4. Fill the phin with boiling water and put the lid on.
5. Adjust the filter insert to make sure the coffee doesn't pour out too quickly.
6. When the coffee has dripped through, stir the milk and coffee together.
7. Fill a tall glass with ice.
8. Pour (through a sieve, if you don't want stray grounds) the coffee over the ice and stir.
9. Enjoy–it's one of the best ways to drink coffee.