Either way, you've deep-fried. You've overcome your fears. Congratulations!
But now you're left with a big pot of oil and you're wondering what to do with it.
Should you just pour it down the sink? Not unless you want to call the plumber.
Should you transfer it to a plastic container and toss it into garbage? Not so fast!
You can reuse your frying oil for the next batch of latkes, doughnuts, or battered fish. But how many times, and under what conditions?
This might be unsatisfying to hear, but there's no right or wrong answer. As J. Kenji López-Alt over at Serious Eats puts it, "Distrust any source that gives a firm answer on the number times you can reuse oil.”
Instead, you'll need to look for signs that the oil has reached its limits.
First, clean the oil: Let it cool completely, then use a funnel to pour it through a fine mesh sieve into a resealable glass or plastic container (we like to use the same container the oil came in). This helps filter out any particles—bits and pieces from breading, for example—that may have contaminated the oil during the cooking process.
Label the bottle "FRY OIL" so that you don't accidentally add it in your next batch of Vegan Chocolate Chip Cookies (it happened to me!).
Tightly seal and store in a cool, dark location. Some recommend storing fry oil in the fridge, while others say the back of the pantry.
The next time you're ready to fry, check for signs of degradation:
- foam on the surface,
- a fishy aroma or any scent that indicates it's "off" or rancid, or
- a dark, murky appearance.
And if you try heating the oil and it smokes before it reaches the desired frying temperature, take it as another indication that it's no longer good to use. (Besides, if you can't bring the oil to the right temperature, your food is bound to be soggy or greasy.)
Fry like with like.
Frying fish will impart a particular flavor and smell to the oil and the same goes for chicken and other meats. To keep your crullers from tasting like catfish, make sure you save fish oil for frying fish and fish alone.
The type of food you fry affects not only the flavor of the oil, but also how quickly the oil breaks down.
Fattier meats, like chicken or bacon, render fat as they cook. According to Serious Eats, this fat can mix with the frying oil, which will cause it to break down faster.
Similarly, different preparations of food—bare, battered, or breaded—contaminate the oil in varying degrees.
Bare foods (like French fries) leave behind fewest particles, followed by battered foods. The worst offenders are flour-dredged foods, which according to Bon Appétit, leave behind particles that eventually burn and impart a bitter flavor. (To solve this problem, add a bit-catching magnet, otherwise known as a carrot, to your fry oil!)
Keep these points in mind when you're choosing your order of operations.
If you're frying potatoes and fish (fish and chips!), for example, fry the bare, neutral-flavored potatoes before you fry the battered fish.
Clean as you go.
If you don't use the handy carrot trick, or you want extra protection, keep a fine mesh strainer by the pot and use it to skim off any particles that come loose, lessening the chances of a bitter, burnt flavor in the oil.
Used oil can, for a time, be more efficient than fresh oil.
As oil breaks down, the molecules become less hydrophobic, which means they can come in closer contact with the food; thus, frying can happen more efficiently! (We learned this, too, from Kenji at Serious Eats This is why you'll hear that some people reserve old oil for mixing with new oil. At some point, however, used oil becomes so much less hydrophobic than in its original state that it enters the food too quickly, which leads to sog and grease.
Now you're prepared to use, store, and reuse your oil. You'll just have to figure out how to get that deep-frying smell out of your house...