Something to think about to use less energy…
1 liter of whole milk
1 tablespoons of stevia / erythritol mixture
1 tablespoon of sugar
100 ml of cream (optional)
1 vanilla stick or vanilla extract (optional)
1 teaspoon baking soda (optional)
10 grams of unflavored gelatin (optional)
Really, you only need milk and sugar. That's it. I like my dulce de leche more creamy, so I add cream.
Sweeteners can be added to taste. I find any store bought dulce de leche overly sweet. They add as much as 1/2 ratio of sugar/milk. Practically ruins the experience.
Erythritol crystals melt at 121 degrees celcius, but do not reduce (chemistry).
Gelatin is to make the dulce de leche denser with a shorter cooking time. It's cheating and not necessary.
Baking soda helps reduce lumps in the dulce de leche. Some recipes have it, but I am suspicious of this ingredient on the end outcome.
I have attempted using an oven to make dulce de leche, because I thought heat is more evenly distributed, and will keep the mixture from burning on the bottom of the pot. Milk has a boiling point of 95 degrees celcius, however, you can set the oven slightly above this temperature. Maybe an infrared thermometer would help to check the temperature of the milk surface.
As opposed to an oven, cooking with a pot on top of a flame can superheat the milk adjacent to pot surface, causing it to boil over and spill from the pot. The bottom of the pot in an oven is unlikely to reach such a high temperature as that of a flame.
In an oven, the top surface of the milk is at more of a danger of burning from the top coil of the oven, from radiative heat transfer.
Also, if you set the oven temperature too high, the fat will separate, or perhaps break down, and you won't get a creamy mixture: just runny oil with chunky parts.
For some reason, it takes FOREVER in the oven. More than 5 hours. Is the moisture not allowed to escape, thus keeping the water in the milk from evaporating?
Place milk, cream, and sugar, and the optional vanilla, in a stovetop pan, and bring to 90 C.
At 90 C, you can optionally add baking soda, and optionally add gelatin.
Stir every so often. You will require progressively more stirring as the milk thickens. You can also turn down the temperature as it thickens to reduce a temperature gradient between the surface and the inside of the dulce de leche. Some people add marbles to encourage self mixing, and perhaps they also create a surface at a higher temperature than the surrounding dulce de leche. I suspect that commercial production of dulce de leche involves ovens with automatic mixing.