When you hear someone comment with cool beans (aka kewl beans, kool beans, and cool beanz), it means that the speaker approves of the comment or the situation that prompted him/her to say cool beans. Not only is this an idiom, according to Time magazine, it’s been in the Oxford dictionary since 2014.
For fans of the sitcom, “Full House” which aired from 22 September 1987 through to 23 May 1995, DJ Tanner used the expression so often that fans and followers of the show followed suit. But the writers of “Full House” weren’t the originators of the expression.
The idiom shows up in Marlene Fanta Shyer’s book “Grandpa Ritz and the Luscious Lovelies” published by Scribner Books (an imprint of Simon and Schuster) in 1985. There on page 30, this appears:
“It’s cool beans!” That’s what Betsy always says when she thinks something is fantastic, and I couldn’t help wondering what she’d say if she could see me now.
In the 1960s, quaaludes, amphetamines and barbituates known as uppers and downers were referred to as cool beans because they resembled jellybeans. They were also known as beans, wacky beans, and cool beans.
The drug-induced positive reaction would therefore be attributed to cool beans thereby creating a positive impression of cool beans.
The reference to cool beans didn’t appear elsewhere in Idiomation’s research. While cool beans as an item is from the 1960s, the expression indicating approval is from sometime between the 1960s and 1985 when it appeared in Marlene Fanta Shyer’s book.
Historically Speaking 