2 to 3 seconds: the fire is medium-high heat, about 375--F, and coals have a faint coat of ash. 3 to 4 seconds: the fire is medium heat, about 350--F, and coals have a light coat of ash. 4 to 5 seconds: the fire is medium-low heat, about 325--F, and coals have a moderate coat of ash.read more >>