とろ火(び)

とろび
noun
low heat; simmer
cooking
1. low heat; gentle flame
the lowest heat setting on a stove, used for slow cooking, simmering, or keeping food warm
とろ火(び)で煮込(にこ)む。
Simmer on low heat.
とろ火(び)にして20分(ぷん)煮(に)る。
Turn to low heat and cook for 20 minutes.
Cook slowly and thoroughly over low heat.

Similar words

The heat levels in recipes, from high to low:

Usage

For long simmering, sauces, and keeping food warm without scorching it or boiling it down.