Deep fryer cooking oil - advice please!
I've spoken to numerous people including cooks/chefs about how long they keep and use cooking oil in their kitchens. I've looked it up on the Internet as well but am still puzzled. There doesn't seem to be a general rule of thumb like with other kitchen techniques.
Some people say they keep it based on length of time. Others say they change it when it gets too dark. I worry about food particles causing bacteria to grow if the oil is left too long. People tell me that's not a problem because once it heats up, bacteria are killed.
So, I wonder what you do at home when you deep fry with oil? Does anyone throw it out after one use? What are some general rules about keeping and re-using it? Thanks for your input!
I use fry oil until it gets to a really dark color, which I determine by a simple little test kit I have. It's just an eyedropper to suck up some oil and a vial with oil that's at its limit. It's never as dark as you think it is when you actually test it. It lasts for quite a few uses, just scoop out the bread crumbs from the bottom of the fryer occasionally, but that's if you have a dedicated fryer like I do. If you're doing it in a pot, then strain it and keep in a jar, I never bothered to refrigerate it back in those days. If I fry fish or something with more of an odor I might change it soon afterwards.
You're right, there's no rule of thumb, except stuff fried in fresh oil tastes the best, so if you're having company it's a good idea to change it just before then.
I let it cool then strain it through a layer of cheesecloth in a fine mesh strainer (a setup with a strainer with or without a funnel, depending on the jar/bottle I'm keeping the oil in with the cheesecloth in the strainer works as a one-step filter). I keep the oil in glass after I use it the first time (the oil I get normally comes in plastic bottles). I do keep an eye on whether its getting dark and I also count the number of times I heat it up. I find that I get about 5 "fries" out of 2 full quarts of Canola oil. I use a deep fry thermometer and the oil almost never goes past 375 degrees F.
The higher you heat it, the more food you fry in it and the less you strain it after you're done the fewer uses you'll get out of it. I heard Alton Brown say on an episode of Good Eats the other day that he keeps his fryer oil in the freezer between uses and gets 7 uses out of it. I may try that if I ever have enough freezer space.