There is provided a method for preserving the temperature of a liquid, the method characterized in including a step for adding an edible-roasting-oil-containing oil to a liquid containing at least 80% by mass of water so that the amount of the edible roasting oil per square centimeter of the area of the surface of the liquid is at least 0.0007 g, the color level of the oil including the edible roasting oil (Y+10×R+10×B) as expressed by the formula Y+10×R+10×B is at least 20 (Y, R and B represent, respectively, the Y value (yellow slide value), R value (red slide value), and B value (blue slide value) measured with a Lovibond colorimeter (cell: 25.4 mm))
