So what were they? One source lists a standard iron ration as:
- 1 lb. preserved meat
- 3 oz. cheese
- 12 oz. biscuit
- 5/8 oz. tea
- 2 oz. sugar
- 1/2 oz. salt
- 1 oz. meat extract (meat broth or bullion perhaps?)
Another source lists an iron ration as:
- 300 grams of hard crackers (such as Zwieback [twice-baked] crackers)
- 200 grams of preserved meat
- 150 grams of preserved or dehydrated vegetables or pea sausage
- 25 grams of artificial substitute coffee
- 25 grams of salt
Then, of course, the US Army's much maligned K-Ration bears mentioning here. Descriptors such as "palatable" and "better than nothing" seem to be used a lot regarding them. There is also the nautical forerunner of hardtack that seems to be at least partial inspiration for the K-ration.
No matter the specific form? Iron rations were notable in their lack of so-called extras such as cigarettes, chewing gum, or instant coffee. They were the bare minimum needed a fully grown, healthy, fit human needed to remain active and were only intended for short term use. Both are vaguely cracker-like in size, appearance, and texture; and are reportedly difficult to chew. The taste was only bearable and better than nothing sounds a lot like damning with faint praise.
This may explain why trail rations are more desirable than iron rations. The former tastes more like "real" food and is more satisfying to the appetite, with the drawback of being bulkier. The latter will sustain an adventurer but will not be satisfying in the least.
May you always roll 20's!