Restaurants keep bread warm by using heated steam drawers as well as commercial drawer warmers and heat lamps or ovens.
Heated steam drawers is how most restaurants keep their bread warm.
Some restaurants may also keep their bread warm by wrapping the bread in foil or towels or storing the bread in baskets with heated stones or rice.
Keeping bread warm during transport can be done by using insulated bags and boxes.
Steam drawers maintain the warmth of the bread as well as the moisture in the bread and keeps it from drying out.
Ovens and warming drawers in restaraunts can heat the bread and maintain the breads temperature in specialized warming drawers.
Commercial drawer warmers are also an essential part of a restaurant and catering business which ensure the bread stays warm and ready for serving.
Heat lamps are sometimes used to keep plated food including bread warm until it is served.
Wrapping the bread in some foil or towels also helps to retain the breads heat, especially during storage or transport.
And bread warming baskets can be lined with napkins and used along with a heated stone or rice to maintain the warmth of the bread.
Some restaurants also have temperature and humidity controlled warming drawers built into the waiter's stations where the bread is kept warm and moist before it's served.