When to Heat Frying Oil Lower and Slower
Sometimes when heating up frying oil, slow and steady wins the race.
While developing our recipes for Bhature and Yeasted Doughnuts, we noticed that if we heated the frying oil quickly over high heat, we had trouble maintaining a consistent temperature during cooking.But if we heated it more slowly, it was easier to keep the oil within our target range. To confirm our observations, we ran some tests.
We heated 2 quarts of oil to 350 degrees over high heat and then turned down the heat to medium to replicate the temperature drop oil experiences when food is added. Though we had lowered the heat, the oil temperature continued to climb for a full 5 minutes, reaching a high of 370 degrees; it then took 20 minutes to drop back down to 350 degrees. (We witnessed a similar phenomenon whether the pot was made of cast iron or thinner, more responsive material like aluminum or carbon steel.) This continued rise in temperature—and the lengthy time it took to return to 350—means that keeping the oil at the target temperature would have required constant adjustment of the burner strength. When we performed the same test on oil that we heated over medium-high heat, the temperature climbed a few degrees after we turned down the heat but then began to drop almost immediately, returning to 350 degrees after just 4 minutes. The oil then stayed within 5 degrees of our target for more than 15 minutes without any adjustment of the dial.