When Should You Use Low-Temperature, Long-Cooking Methods?

High heat browns the surface quickly but does not make heat reach the center any faster; with thick cuts, this can leave the outside dry and the inside raw. At a low temperature, the gap between the surface and center narrows, and heat moves slowly and evenly. The muscle fibers contract less and lose less water. The tradeoff is time: the same dish takes two to three times longer to cook, and the oven runs for that entire time. This method is best for days when you have time.

This method works best for cuts rich in connective tissue. Cuts such as lamb shank, beef shank, neck, collar, and ribs become fork-tender when cooked for hours at 120–150°C / 250–300°F, as the collagen in their connective tissue slowly turns into gelatin; the meat becomes tender enough to pull apart with a fork, and the sauce thickens on its own. The same cuts become tough when cooked at high heat. Use a lidded casserole or a baking pan tightly covered with foil. The sauce naturally thickens toward the end. Once cooking is complete, let the meat rest in its own juices.

Low heat is useful for other tasks too. Milk-based desserts and crème caramel are cooked at a low temperature in a water bath to keep them from curdling. Meringue is dried at low heat. Tomatoes, fruit, and herbs are dried for hours at 90–120°C / 195–250°F. If whole poultry is cooked at a low temperature and then exposed to high heat during the final minutes, the inside stays moist while the skin turns crisp. The same approach works for thick cuts of meat, with the higher heat at the end forming a crust. When drying food, prop the oven door open slightly with a spoon handle.

Temperature measurement is even more important with this method. Color develops slowly at a low temperature, so doneness cannot be judged by looking at the outside; use the internal temperature to decide. Leaving a probe thermometer in the food lets you monitor it without opening the lid. The thickest part of poultry should reach 74°C / 165°F. During long cooking, also account for how long the food spends in the 5–60°C / 40–140°F range. If the oven is set too low, the food stays in that range for a long time, so do not set the oven below 120°C / 250°F. Take each reading at the same spot.

A few practical details make the process easier. Searing the meat in a pan before it goes into the oven adds color and flavor; low heat alone will not produce that color. Steam stays inside a covered dish and keeps the meat from drying out. Use only a small amount of liquid, since the food releases its own juices. Avoid opening the oven door often because, at a low temperature, it takes a long time to recover lost heat. Let cooked food rest before slicing it; meat cut while hot releases its juices. Leftovers also reheat better the next day when prepared this way.