A food heating method of using an exothermic gel to minimize metallic odors in a presence of food or within a food container. The method can include generating an exothermic reaction that produces heat by exposing a mixture of the expandable exothermic gel-forming composition to water and one or more electrolytes in the absence of air to form the expandable exothermic gel, the mixture comprising first metallic galvanic particles and second metallic galvanic alloy particles, a metallic secondary shell comprised of at least one transitional metal, and a super absorbent polymer; and suppressing at or about 95% hydrogen byproducts of the exothermic reaction within the gel while in the presence of the food or the food container so that steam permeates around the food or the food container.

Disclosed is a device for thawing frozen sushi, the device having a tray on which the frozen sushi is placeable with frozen rice as a lower surface, and being capable of applying vapor, water vapor, or steam to the lower surface from a hole provided in the tray at the time of thawing the frozen sushi, and a surroundings of the tray are open to ambient air during thawing of the frozen sushi.

Disclosed is a device for thawing frozen sushi, the device having a tray on which the frozen sushi is placeable with frozen rice as a lower surface, and being capable of applying vapor, water vapor, or steam to the lower surface from a hole provided in the tray at the time of thawing the frozen sushi, and a surroundings of the tray are open to ambient air during thawing of the frozen sushi.