Grape-Nuts is a breakfast cereal produced by the Post company. The cereal dates back to 1897. The name (allegedly) was given because the little grape nut bits look like grape seeds. There are other versions of the name too. C.W. Post, the creator of the breakfast food was a former employee of Kellogg's, famous for corn flakes and other cereals as well. He left Kellogg's and formed his own company named Postum.
The cereal is made from wheat, barley, salt and yeast and fortified with vitamins. There is no sugar added. The little kernels are very crunchy, almost disturbingly hard. The "firmness" does keep them from getting soggy in milk. In the early days the cereal was marketed as a health cure-all. Now it is an unsweetened, high fiber cereal. Each 1/2 cup serving is about 210 calories and offers 7grams of fiber.
Grape nuts have other uses too in addition to being a breakfast cereal. They can be used to make cookies, energy bars, muffins and even moistened and used as a base (crust) for a pudding dessert. They can also be used as a crunchy topping for ice cream.
If you don't have grape nuts then you can substitute:
Here are the general production steps involved in making grape nuts cereal. This just an overview and does not include every step in the process. It does explain how the cereal starts as a whole grain and ends up as the grape-nuts cereal. The actual process includes several baking steps.