Dulce de leche: How to turn condensed milk into a tasty caramel sauce

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How to use the Maillard reaction to make delicious dulce de leche 鈥� the ultimate comfort food when you are stuck indoors, says Sam Wong

By Sam Wong

22 April 2020

What you need

Can of condensed milk

Milk

Sugar

BEING trapped inside has led many of us to rummage in our kitchen cupboards in search of inspiration. I suspect I鈥檓 not the only one who found a tin of condensed milk that I鈥檓 not sure why I bought. If you also have a neglected tin, there are few more delicious things you can make than dulce de leche.

Meaning 鈥渟weet of milk鈥�, dulce de leche is a kind of caramel sauce that is popular in South America. The traditional method begins with milk, but using condensed milk speeds up the process. Condensed milk is milk in which about 60 per cent of the water has been evaporated, and sugar has been added. Evaporated milk is similar but unsweetened, so it won鈥檛 work for this.

Remove the label and put the tin on its side in a large pot and cover with water. Then simmer it for 2 to 3 hours, depending on how dark you like your caramel. It is crucial the tin is submerged the whole time because this stops overheating causing a pressure build-up and a potential explosion. Liquid water won鈥檛 exceed 100掳C, so a submerged tin won鈥檛 get hotter than this either.

When the time is up, use tongs to take the tin out of the water. Make sure you let the tin cool completely before opening it, or else hot dulce de leche could shoot out. The sweetened milk will have turned into a thick brown paste that you can spread on toast or spoon on to fruit or ice cream.

Strictly speaking, the reaction responsible isn鈥檛 caramelisation. This term describes what happens when sugar molecules break apart and generate a range of other flavour compounds. This happens only for sucrose 鈥� table sugar 鈥� at temperatures above 170掳C.

Just as with caramelised onions, which I covered a few weeks ago, the chemical process here is the Maillard reaction. This occurs when sugars react with amino acids, the components that make up proteins, which are abundant in milk. The products are a range of flavoursome compounds.

Maillard reactions happen at lower temperatures than caramelisation, but are quite slow until you get to about 120掳C. In condensed milk, the high concentration of compounds for reactions and the prolonged cooking time can achieve browning even at 100掳C.

You can also make dulce de leche the more traditional way, with a litre of milk and 250 grams of sugar, gently simmered on the stove. This takes many hours but can be sped up with a teaspoon of bicarbonate of soda, which raises the pH, accelerating the Maillard reaction. Even so, it may take 2 hours, and needs frequent stirring.

Alternatively, try cajeta, a version made with goat鈥檚 milk, which needs a mere 45 minutes or so of simmering. Goat鈥檚 milk is lower in lactose than cow鈥檚 milk, so it is less likely to burn, and has a higher concentration of various amino acids, which confer thermal stability and umami taste.

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