RE: Food Science
To UncleVic: Yes, I am talking about big fryalaters. The ones that hold gallons of shortening. I spent time draining and refilling those things years ago. You drain it, get all the little bits of loose breading or whatever out, MAYBE do some kind of soapy washout and rinse it (the leftover water boils away explosively) then you turn on the burner and start throwing huge blocks of shortening in there. I would imagine that most 24 hr operations have two fryers so they can service one or the other in off-peak hours.
Now, the article I read about saving a ladle of the old oil is from the LA Times, and I don't think they were pulling our legs about this. They explained the science underlying this practice. You may be right about old oil causing new oil to break down more quickly, but...when you are frying mass quantities of whatever, you will be changing the oil pretty frequently, and I think the concept is to maintain a consistent flavor from batch to batch. Anybody else know about this?