Cooling down with Vietnamese iced coffee

One of the lovelies on many Vietnamese restaurant menus is the iced coffee, a sweet, coffee-flavoured treat that you might sometimes put in the dessert category.

It often tastes like it's made with a couple of teaspoons of instant, and features a generous slug of condensed milk; at its best it's a filter brew of Vietnamese robusta beans that give it distinct and powerful developed roast flavours and a solid caffeine kick.

So when brothers Bao and Tuan Hoang from the Roll'd Viet takeaway chain approached Sensory Lab's Ross Quail to develop a specialty version of the drink, Quail knew he had an interesting coffee problem on his hands.

Roll'd had been using Trung Nguyen brand coffee, which is Vietnamese robusta beans.

"Trung Nguyen is the biggest coffee player in Vietnam," says Bao Hoang. "He's got maybe 500 cafes, and he owns a fair few plantations."

"Coffee in Vietnam is everywhere," Bao Hoang says. "Every second shop is a cafe."

And the coffee culture is getting increasingly boutique – something the brothers want to reflect in Roll'd's new brew, which you should be able to sample at some Roll'd stores from late March.

"We've approached it as food engineering – how can we get the best flavour out of the product, and make it consistent," Quail says.

Roll'd has outlets in Melbourne, Brisbane, Sydney, Canberra and is expanding into Perth, so, says Quail, "We had to make sure the knowledge of how to make it was documented, so everyone makes the same coffee."

After numerous roasting and tasting sessions, they've settled on a blend of Brazilian and Colombian beans, with 10 per cent Vietnamese Jade Mountain washed arabica.

There's a strict recipe – 50 grams of espresso, 100 grams of ice and 80 grams of evaporated and condensed milk. Condensed milk tends to clump on ice, says Quail, hence the mix.

Bao Hoang says they decided to use espresso rather than drip filter coffee to maintain consistency. "With drip filter, if you go a minute either way you change it."

Quail says they've roasted the blend darker than usual for Sensory Lab, but they haven't gone overboard.

The result – served in a glass with ice and the condensed/evaporated milk on the side for pouring – is milder than a traditional Vietnamese iced coffee, without the developed roast flavours, though it does have a sweet, dark sting in the tail.