RE: Chicago hot dog rolls
Vienna Beef has their poppy seed buns made for them by one of two Chicago bakeries: Alpha or Gonnella. I'm not sure which one. Their food service buns are par baked and sold in a steamer box. When fresh, their shelf life is only seven days. Freezing them extends the shelf life, but once thawed, their on the clock and must be used within a matter of days. Hot dog stands outside Chicago and Milwaukee can purchase the food service buns frozen from Sysco or Vienna Beef. Vienna's retail buns(those shipped in the kits) are completely baked and steaming will turn them into sponges. I believe the VB dogs and buns in the kits, shipped to the public are frozen. Once thawed, the buns are ready to serve.