Tea is sometimes called “hot leaf juice.” This was popularized by the American animated television series on the Nickelodean channel, Avatar: The Last Airbender, in the episode “City of Walls and Secret” that originally aired on September 22, 2006:
 
UNCLE IROH: Euch! This tea is nothing more than hot leaf juice.
PRINCE ZUKO: Uncle, that’s what *all* tea is.
UNCLE IROH: How could a member of my own family say something so horrible!
 
“Tea is just leaf soup” is a similar tea saying.
         
 
Wikipedia: Avatar: The Last Airbender
Avatar: The Last Airbender (Avatar: The Legend of Aang in some regions) is an American animated television series that aired for three seasons on Nickelodeon. The series started in February 2005, and concluded with a two-hour episode on July 2008. Avatar: The Last Airbender is set in an Asiatic-like world in which some people are able to manipulate the classical elements by use of psychokinetic variants of Chinese martial arts, known as “bending”. The show combines the styles of anime and American cartoons, and relies on the imagery of various East Asian, Inuit, Southeast Asian, South Asian, and New World societies. The series follows the adventures of protagonist twelve-year-old Aang and his friends, who must bring peace and unity to the world by ending the Fire Lord’s war against the other three nations. The show is obtainable from various sources, including DVD, the iTunes Store, and Amazon Video.
 
IMDb (The Internet Movie Database)
Avatar: The Last Airbender (TV Series)
City of Walls and Secrets (2006)
Quotes
Uncle Iroh: Euch! This tea is nothing more than hot leaf juice.
Uncle Iroh: Uncle, that’s what *all* tea is.
Uncle Iroh: How could a member of my own family say something so horrible!
(...)
Officer: This is the best tea in the city.
Uncle Iroh: The secret ingredient is love!
(...)
Uncle Iroh: Would you like a pot of tea?
Prince Zuko: We’ve been working in a tea shop all day. I’m sick of tea!
Uncle Iroh: Sick of tea? That’s like being sick of *breathing*! 
 
Google Groups: rec.arts.anime.misc
Avatar 9/22: ......................................
Phillip Thorne
9/22/06
Because the subject line doesn’t say it: Episode 2.14, “City of Walls and Secrets.”
(...)
Don’t forget the C-plot at the tea shop!
 
Iroh: “This tea is nothing more than hot leaf juice!”
Zuko: “Uncle, that’s what *all* tea is.”
Iroh: “How can a member of my own family say something so horrible?”
 
YouTube
hot leaf juice
woonie
Published on Dec 5, 2008
So… what is tea?
0:10
“This tea is nothing more than hot leaf juice!”
(From the American animated television series Avatar: The Last Airbender.—ed.)
   
Twitter
Dismal Moron‏
@Dismal_Moron
@Avatar_Quotes Uncle: “This tea is nothing more than hot leaf juice!”  Zuko: “Uncle - that’s what all tea is.” (BK: 2, CH: 14)
3:44 PM - 24 Oct 2009
   
Reddit—Shower Thoughts
Tea is just hot leaf juice
submitted December 29, 2015 by UlfarrOT
 
Reddit—Funny
This tea is nothing more than hot leaf juice (imgur.com)
submitted October 17, 2016 by Ask-if-I-Like-Lemons
 
17 March 2017, Western Advocate (Bathurst, New South Wales), “Farmers needing rain,” pg. 2:
In reality, though, isn’t tea just hot leaf juice?