I came across this quote about "nothin' tea" from "The Martian", though I haven't read the book.
I started the day with some nothin’ tea. Nothin’ tea is easy to make. First, get some hot water, then add nothin’.
I googled for "nothin' tea", and most hits I got were for the book.
Are there any more common terms for this concept, apart from "hot water"? An example usage would be
My grandma sometimes has ____ - not because she's stuck on Mars, but because of problems she has with tea.