I remember the first time I heard about making dulce de leche by cooking a sealed can of sweetened condensed milk in simmering water. You’ve likely heard the trick: leave the can unopened, keep it submerged, and simmer for several hours until the milk transforms into a rich caramel. I had to try it and was amazed by how thick, sweet, and perfectly caramelized the result was from such a lazy method.
Over time I grew wary of that technique. Reports of cans exploding while simmering made me uneasy. Whether the water level dropped or pressure built inside the can, explosions did happen. I also worried that the can lining wasn’t designed for long, low-temperature cooking and might leach undesirable chemicals into the caramel. The temptation of an easy caramel was strong, so I adapted the technique to avoid both the safety and chemical concerns.
Instead of leaving the condensed milk in the can, I transferred it into clean canning jars. That not only reduced the risk of exploding metal, it opened the door to infusing the dulce de leche with flavor. For this version I split and scraped a vanilla bean and added its seeds and pod to each jar before filling with sweetened condensed milk. I tightened the lids fingertip snug, placed the jars in a slow cooker, poured hot water to come about an inch above the jars, set the cooker to low and let it go for eight hours while I slept. In the morning I turned off the slow cooker and left the lid off while the jars cooled in the water until it reached room temperature. A couple of hours later, when the jars were cool enough to handle, they contained a beautiful, velvety brown dulce de leche.
I refrigerated two jars and opened another to taste. The texture was perfect: thick, luscious, and silky. We grabbed fresh apples, sliced them, and spent a happy morning dipping and devouring apple slices slathered with this slow-cooker dulce de leche. Even family members who usually avoid fruit happily abandoned their restraints to scoop creamy vanilla-scented caramel onto crisp apples.
This makes an excellent caramel apple dip, but it’s not limited to that use. It’s fantastic anywhere a recipe calls for caramel or dulce de leche: use it between cake layers, as a cookie filling, dolloped over ice cream, stirred into coffee or hot chocolate, or simply eaten by the spoonful. No matter how you use it, it’s a treat.
Cook’s Notes
- Safety and can linings: This jar method is safer than cooking the milk in a sealed can. Cans have internal linings formulated to protect contents from metal, but those linings are not intended for prolonged heating. A jar is a more predictable vessel: if a jar breaks, it typically cracks and leaks rather than detonating, which makes cleanup unpleasant but safer than an exploding can.
- Flavor variations: I used vanilla bean for this batch, but you can experiment. A tablespoon of bourbon or dark rum would add depth, or try spices like cinnamon or cardamom. Infuse the milk before cooking and enjoy the subtle flavor notes that develop during the slow caramelization.
- Storage: If the lid is clean and sealed, rinsed jars stored in the refrigerator should keep well for at least two weeks. I haven’t tested freezing; if you try it, leave some headspace in the jar to allow for expansion and report back with results.
Slow-Cooker No-Stir Dulce de Leche in Jars {no cans}
Rebecca Lindamood
Ingredients
Per Batch of Slow-Cooker No-Stir Dulce de Leche in Jars:
- 1 can sweetened condensed milk 14–16 ounces
- 1 half of a vanilla bean split and scraped; seeds and pod reserved
- 1 pinch salt
- 1 pint sized canning jar with a clean two-piece lid
Additional equipment needed:
- 1 slow cooker deep enough to hold lidded pint-sized canning jars with at least an inch of water above them.
Instructions
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Add the split and scraped vanilla pod and seeds to a clean pint canning jar. Open the can of sweetened condensed milk and pour it into the jar, scraping the can to get all of the milk. Add a pinch of salt. Screw the lid on fingertip-tight, invert and right the jar a few times to distribute the vanilla, then place the jar(s) in the slow cooker. Add hot tap water to cover the jars by about an inch. Place the slow cooker lid on, set to LOW, and cook for 8 to 12 hours. When finished, turn off the slow cooker and allow the jars to sit undisturbed until the water cools to room temperature. Rinse the jars, refrigerate, and use within two weeks.
Nutrition
Nutritional information is an estimate and provided as a courtesy. Calculate nutrition based on the actual ingredients you use if needed.
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