> > > > They haven't changed the grease since the restaurant opened more than forty years ago.
> > >
> > > I'm surprised that's even legal.
> > >
> > > Gri"yummy???"shny
> >
> > I just looked it up. It's Dyer's Hamburgers, and the grease is EIGHTY-FIVE years old.
> >
> > I don't think it's the *same* grease. After having millions of patties fried in it, it probably renews itself.
> >
> > --Jez"doesn't taste weird"zika
>
> Question 1: Who said it was legal?
> Question 2: What does rancid mean?
> Question 3: Do the people in Memphis eat there or just the tourist?
> Question 4: What is the death toll, so far?
> Question 5: Is their policy any different from MacGreaser's?
> Question 6: What happens to a car engine if you drive it for years without an oil change?
> Question 8: Why?
> Howard

Asking why Dyer's would do this is a good question, actually. There's no reason that it wouldn't be legal, because frequently reused cooking grease is not necessarily toxic. The problem is that it's really really inefficient and stupid to keep on using it.

Just like car oil, deep-fryer oil occasionally has to be changed. This is because every time it's used, the oil's smoke point gets lower. In other words it's heating at a lower temperature, which means it takes LONGER to cook the hamburgers; and the longer they take to cook, the MORE grease and oil the burgers absorb. So instead of adding more flavour, Dyer's old grease is adding *more fat and carcinogens* to the beef patties. Oh joy. Their mileage, of course, varies depending on the oil used and the items that are fried. But there's a definite limit to the oil's lifetime when it picks up molecular business from the foods and eventually starts breaking down, as seen by the lower smoke point. Heat and oxidative processes break the oil down into free fatty acids, and these are what give off the typical smell of oils or fats gone bad.

My guess is that Dyer's may not be changing their oil. However, they must certainly be topping it up with new oil (something with a high smoke point like peanut oil or safflower, perhaps) to replace the grease continually lost by cooking vaporization and burger absorption.

Wolfspirit