Why is Grape Nuts cereal called that?!
Answers: when it contains neither grapes, nor nuts?
Grape-Nuts was introduced in 1898 by Charles W. Post, founder of the company that was later to become a division of General Foods and inventor of such other gustatory delights as Post Toasties. C.W., as he was known, was given to devising extravagant names for his products, with advertising claims to match.
Post Toasties, for instance, was originally known as Elijah's Manna, although Elijah had not actually endorsed it, having expired several thousand years earlier. In touting the advantages of Postum Cereal Food Coffee over conventional coffee, Post accused the latter of containing "poisonous alkaloids" that caused rheumatism, "coffee heart" (true enough, I guess), and other disabilities. A diet of Postum and Grape-Nuts, coupled with abstention from coffee and "poor foods," presumably meaning those made by Post's competitors, would cure "any known disease." The brand name Grape-Nuts was conceived in a similar spirit.
Nonetheless, there was a rationale, however thin, for the name. The product contained maltose, known at the time as "grape sugar," and it did have a nutty flavor. Moreover, bearing in mind that the name is properly spelled "Grape-Nuts" and not "Grape Nuts," one might argue that while there were generic commodities known as grapes and nuts, there was nothing called grape-nuts, in the sense that there were cashew nuts, and thus the name could have no tendency to deceive. A fine distinction, I suppose, but that is what we have lawyers for.
Anyway, the 1906 Pure Food and Drug Act specifically excluded "fanciful" (as opposed to deceitful) trade names from prosecution, and when the FTC set up shop in 1914 it showed no inclination to get persnickety about things. We might finally note, Winfield, that while you and I are insignificant insects (well, you are, anyway), General Foods is a multinational megacorporation. But of course that has no bearing on the matter at all.
-- CECIL ADAMS.
It used to explain why on the back of the packet. From memory I thought it was because they called the pans they used to bake the stuff in "Grapes". I know that sounds strange but this is what I remember it as.
Putting your search engine to use would've helped you find this "Grape-Nuts is a breakfast cereal developed by C. W. Post in 1897. Post was a patient and later competitor of the 19th-century breakfast food innovator, Dr. John Harvey Kellogg. Neither grapes nor nuts have ever been ingredients in the cereal. The original formula for Grape-Nuts called for grape sugar, which is composed mostly of glucose unlike most other sugar sources and food sweeteners which are principally sucrose. This, combined with the "nutty" flavor of the cereal inspired its name. But some employees at Post claim that the cereal got its name because the tiny nuggets resemble grape seeds or grape "nuts.""
However, that excerpt is from Wikipedia and since anyone can post text there, the reliability of anything on that site can be questionable. I wouldn't count on that being the actual truth unless you find similar information elsewhere (and I figured you could search for that yourself as easily as I could).
I think the nuts are maybe oats? and there might be preserved grapes in it too.
Just a guess.