“I’m a chemical engineer. I convert beer and wine into urine”

The “convert beer into urine joke” has been popular since at least the 1990s. About 2008, a joke called the “Wisdom of a Retiree” circulated from an uncredited source:
 
“I’ve often been asked, ‘What do older people do once they retire?’ Well, I have a Boomer retired friend who has a chemistry background and one of the things enjoyed most is is turning beer, whiskey, and wine into urine. And, by golly, he’s pretty damn good at it!”
 
 
Google Groups: alt.tasteless
The Last Temptation of Chris
Sean Med
12/20/97
With all this maudlin hand-wringing about blubbery former comedian Chris Farley trying to emulate the life and death of his idol John Belushi, am I the only one who remembers that there was yet another beloved household name who made
an indelible mark on the world before leaving us, all too soon, at the age of 33? That’s right, you remember Him, don’t you? The parallels are frightening…
(...)
Christ: Turned water into wine.
Chris: Turned beer and whiskey into urine.
   
Google Groups: alt.society.boomers
What Good R Boomers?
lanier
5/28/08
I’ve often been asked, “What do older people do once they retire?”
 
Well, I have a Boomer retired friend who has a chemistry background and one of the things enjoyed most is is turning beer, whiskey, and wine into urine.
 
And, by golly, he’s pretty damn good at it!
 
Google Books
Uncle Berl:
Collected Short Stories
By George Oscar Lee
Xlibris Corporation (Xlibris.com)
2009
Pg. 72:
I may add in conclusion that I’m very fortunate to have a few friends who have a chemical engineering background, and one of the things we enjoy most is turning vodka, scotch, beer, or wine into urine. And what’s more, we’re pretty damn good at it. Ciao.
   
Google Groups: Barkemas
FW: Wisdom Of A Retiree:
Charles Barkema
5/6/09
Wisdom Of A Retiree:
I’ve often been asked, ‘What do you old folks do now that you’re retired?’  Well..I’m fortunate to have a chemical engineering background, and one of the things I enjoy most is turning beer, wine, Scotch, and margaritas into urine.
     
Going Like Sixty
Harold the Chemist – An Inspiration
Posted on October 20, 2010 by goinglikesixty
(...)
Harold Schlumberg is such a person:
 
“I’ve often been asked, ‘What do you old folks do now that you’re retired?’ Well…I’m fortunate to have a chemical engineering background and one of the things I enjoy most is converting beer, wine and vodka into urine. I do it every day and I really enjoy it.”
 
Google Books
All Kinds of Humor:
Jokes, Quips, and Fun Stuff for Many Occasions, Book 2
By Frank Verano
Xlibris (Xlibris.com)
2012
Pg. 199:
A quote from a retired old man, Harold:
 
“I’ve often been asked, ‘What do you do now that you’re retired?’ Well, I’m fortunate to have a chemical engineering background, and one of the things I enjoy most is converting, beer, wine, and whiskey into urine. It’s rewarding, uplifting, satisfying, and fulfilling. I do it every day and I really enjoy it.”
 
The Commentator
Great Yorkshire Quotes: A Tyke’s retirement—Converting beer, wine and whisky into urine
England’s greatest county never fails to impress. Now then…
by Yorker on 29 September 2013 15:05
Here in Yorkshire, you’re never short of a bit of down to earth humour. Sitting in Bar T’at in Ilkley, there’s an interesting addition on the notice board about: “The importance of an occupation after retirement”.
 
It features the photo of an elderly looking gentleman called Harold. He says: “I’ve often been asked: What do you do now that you’re retired.”
 
He answers:
 
“Well… I’m fortunate to have a chemical engineering background and one of the things I enjoy most is converting beer, wine and whiskey into urine. It’s rewarding, uplifting, satisfying and fulfilling. I do it every day and I really enoy it.”
   
Slate
NOV. 6 2015 3:30 PM
That Viral, 89-Year-Old Stand-Up Is a Shameless Joke Thief
By Forrest Wickman
(...)
Esterly:
People wonder what old folks do with their time. Actually, I have a chemical engineering background, so I spend a lot of time converting beer, wine, and liquor into urine.
 
Old joke:
This one has been going around since at least 2010, appearing online and even in books of jokes.