Comment by analog31
3 hours ago
I work in an area that involves, among many other things, analysis of cooking oil in factories. It might be hard to pin down the terminology of "reused" frying oil, because many of the frying processes are continuous. The raw material goes through a vat of hot oil on a conveyer and comes out the other end dripping with oil
The quality of the oil is continuously monitored, and new oil goes in while old oil goes out in the fried food itself. The crunchy and salty aspects make it palatable to eat oil. The oil doesn't actually spend a long time in the vat before coming out in the product.
Analogous is the label on vodkas that says “distilled N times”, as if they were making it in batches using pot stills.
Vodka is made almost exclusively in industrial-scale continuous fractionating columns. The concept of it being “distilled N times” is farcical. (But technically defensible because you can map the output of the fractionating column to any arbitrary N via equivalence relationships.)
That's interesting and nice to know.
Good point that industrial use might not strictly be "reusing" - that might apply more to restaurants where they have big vats of frying oil and keep dipping food in it for multiple days. Even worse I've seen small scale home fryers where people neglect to change the oil for who knows how long - but that's probably not super common.