An oven bag, cooking bag or roasting bag is a bag used for the roasting of meat or other food in an oven. They may be made of plastic or culinary parchment. A bag helps to keep the food being cooked moist by trapping the moisture in the bag and preventing it from escaping into the oven; as such, it serves a similar purpose to basting. The plastic used for manufacture of the oven bag must be chosen so that it will not melt at the temperature during cooking and thus spoil the food. To this end, many oven bags are formed from a heat-resistant nylon.
The inventor of the plastic-based cooking bag is Gordon Lawry. However, Mr. Lawry was working for a company at the time and received payment of approximately 15 cents.
Oven bags should be carefully placed so that the bag does not come in contact with any hot surfaces in the oven, such as heating elements or oven racks. These may cause the bag to melt, smoke, or catch fire.