"Man That Woman Can Age Whiskey" ???

I was listening to an old radio show Burns and Allen and George Burns is talking to Bill Goodwin about his mother-in-law.

Bill) Oh I take it you don’t get along with your mother-in-law
George) Man, that woman can age whiskey

Now that got a very big laugh but what exactly does it mean? Does it mean his mother-in-law is old? Or that she is mean? Or what?

I kinda vaguely get it. He’s implying that she’s so hard to get along with, she makes you age, just being around her . . . she even has that effect on whiskey.

It might be funny if you’re sitting in an audience and expecting to hear something funny.

Well, whisky is aged in oak barrels, and oak is a traditionally strong wood, so kinda like saying she’s tough as nails? Or thick as a plank? Or… something…

I think panache has it.

Tough as oak/barrel-shaped/smokes a lot/makes you want to hit her with a large mallet?

She’s so unpleasant to be around that time seems to actually dilate, …