By the 1950s, it [Schlitz] was the nation's largest brewer, with additional breweries outside Wisconsin. But in the '60s and '70s, Jos. Schlitz Brewing Co. did some things that affected the beer's taste.
In 1967, Schlitz patented a process that accelerated fermentation, according to the book "Breweries of Wisconsin" by Jerry Apps. That was followed by apparent changes in ingredients, including a different type of barley and the use of corn instead of barley, Apps wrote.
Drinkers noticed and turned away, said John Gurda, Milwaukee historian and author.
"That stuff was undrinkable in the '70s," Gurda said. "It had a very pronounced chemical taste."
As I recall, it was the only beer that could give you a headache while you were drinking it. The bottled Schlitz will be brewed using the formula from before those changes. (The article says a slightly different formula is used for Schlitz in cans.) Looks like Schlitz still won't be available, as it's signage would say, "on draught".
P.S. Belated happy Beer Day.