Wheat can be cooked as is but most people will grind the wheat for flour. My favorite manual grain mill is the Wondermill Junior. Grinding flour is hard work, so you will probably prefer an electric mill, too. Wondermill and NutriMill both make very good electric mills in the lower $200 price range. I found my electric mill in a second hand store for about $30, so you might also start checking places like Goodwill and even online — Craigslist or eBay.
With this method, you needn’t worry about where to get water to add and since your food is cooked in the caning process, you can even eat cold if necessary. Imagine a jar of pork in your favorite marinade sauce. Terriaki beef or chicken. Strips of flank steak marinated in A1 and a touch of hot sauce. Heat this up on a forman grill or charcoal grill. The menu is limited by ones imagination only. Much healthier than all the salt in canned or freeze dried food. They put in the salt only to insure they do not lose a penny in sales as a result of in mass production, a batch does not cook long enough, or a product sits on the shelf too many decades.
The rest of the fire risk will be from all of the things you bring into the bunker. Your power system could spark a fire, and your supplies could provide it fuel. And while you’ll probably (hopefully) also have fire extinguishers in your bunker, even a small fire could be a serious risk for the oxygen levels in your bunker. Fire uses oxygen, and you need to be sure your ventilation system can replenish that oxygen very quickly.
Though its light weight and long shelf life are ideal for navigating harsh conditions, freeze-dried food is probably most famous as a cultural curiosity: Like many Americans, I discovered it in a museum gift shop, gawking at the styrofoam-like ice cream that astronauts used to have for dessert. More recently, I encountered it at a disaster preparedness convention in Raleigh, North Carolina, where smiling, gray-haired preppers manned tables piled with plastic bags full of vegetables, meats, and stews.