Dulce de leche is a popular South American caramel sauce composed of only two ingredients: milk and sugar. In fact, the name literally translates to “milk jam” (side note: it is pronounced as “dul-say,” as opposed to “dul-che” — you’ll gain some cool points for this). According to Alton Brown, dulce de leche most likely evolved as a way to preserve milk in the pre-refrigerator era. Though its flavor is complex and layered, dulce de leche is deceptively simple to make. So how does combining milk, sugar, and heat turn into something as lucious and spoonable as dulce de leche? The answer lies in science — more specifically, chemistry. ~ From Food52
The Maillard reactions are responsible for the browning of many foods including meat, the brown color on a loaf of bread, coffee beans, “caramelized” onions and….dulce de leche!. Maillard reactions take place between sugars like glucose and amino acids that are free or part of proteins. The Maillard reactions also require intense heat (250˚F/120˚C) – but not quite as hot as the caramel forming reactions. When we heat milk and sugar – the proteins (remember, proteins are made of amino acids) in the milk undergo Maillard reactions with the sugar to generate nutty, complex caramel flavors.
Materials
- 3qt saucepan
- large, sturdy spoon
- measuring cups (liquid and dry)
- measuring spoons
- wire mesh strainer
- kitchen thermometer
Ingredients
Makes 1 cup
- 1 quart whole milk
- 1 cup sugar
- 1/2 teaspoon kosher salt
- 1 vanilla bean, split
- 1/4 teaspoon baking soda. The baking soda keeps the milk proteins from coagulating too much and everything getting lumpy.
Instructions – READ FIRST
When you see the boldface blue font, document that step with a photo on your blog
The goal of this lab is to make two dulce de leche sauces of different colors – one darker, one lighter. The color is a function of how long the Maillard performing reactions are allowed to proceed. Read all the instructions first, and then decide how you are going to make your two different colored sauces
Option 1 – run two saucepans side by side, and make two batches. Simple, but requires more resources
Option 2 – cook one batch, then the second. Simple, but take a long time, as each batch is ~ 2 hours.
Option 3 – cook one batch, pour out some dulce de leche when the color is light, then let the rest keep heating until a darker color is achieved. Slightly trickier, but takes less time and resources.
- Mix the first four ingredients together in a saucepan over medium heat until the sugar dissolves. Take off the heat.
- Stir in the baking soda, then put the mixture back on the stove over low heat. You want the mixture to bubble along the edges, but not to boil over.
- Let the mixture cook for 1.5 – 2.5 hours, stirring occasionally. Attach a thermometer to the pan so that the tip of the thermometer is immersed in the liquid (but not touching the bottom of the pan). Alternatively, periodically measure the temperature starting when you first see the tan color, and then every few minutes thereafter until you have the color you want. The color will begin to change from white to tan after an hour or so, then will darken rapidly. Keep a close eye on it now, stirring constantly. The longer the sauce stays on the heat, the darker it will get. As the mixture darkens it will become thicker, and also nuttier. After your dulce de leche reaches your desired tone of caramel color, take it off the heat and let it cool slightly.
- You want two dulce de leche sauces of different colors – one darker, one lighter. If you are using Option 3 above, then pour or spoon some out into the strainer (step 4) when it has darkened only slightly, then let the remaining sauce darken further.
- Push the sauce it through a fine mesh strainer into a clean jar or bowl by smoothing it against the wire mesh with the back of a spoon.
Dulce de leche keeps, refrigerated, for up to four weeks. Eat it over ice cream, spread on toast, or right out of the jar.
On your Blog
Take photos
- Of your two batches of dulce de leche (light and dark) side by side, close-up.
- Make a table of photos the temperature of your sauce and the color
| Temperature | Photo of Sauce |
Post a video in which you…
- Taste test the light and dark dulce de leches: The darker sauce is supposed to be thicker and nuttier, while the lighter sauce is sweeter and thinner. How do your sauces compare?
- Describe what went really well during your dulce de leche making
- What would you change if you repeated this process again
Answer the following questions on your blog
- Why is the darker sauce less sweet?
- At what temperature did you see a significant change in color? Why is this significant?