When you deepfry something, what do you do with the leftover grease?

October 25, 2004 7:12 AM

When you deepfry something, what do you do with the leftover grease? Chase it down the drain with really hot water, put it in a container and toss it, or reuse it? And if you re-use it, do you strain it first, and does it make a difference whether you used the grease for meat or fish vs. potatoes or oreos? Is rancidity a concern?
posted by stupidsexyFlanders to food & drink (22 answers total)

We've got a self-contained electric deep-fryer, and unless the oil is really nasty -- and I mean absolutely disgusting -- we leave it in there and close the top. Makes no difference what's been fried (although we don't fry fish, as fried-fish-smell is impossible to get rid of). It's often been in there for six months at a time, and it's never gone rancid. And as much as people will tell you that fresh oil tastes better, I find that I prefer foods fried in the old, crusty, black-as-night stuff. But maybe that's just me.
posted by uncleozzy at 7:27 AM on October 25, 2004

Bag it, bin it. Don't flush it.

"Solidified fat is one of the biggest causes of blocked sinks and can lead to blockages in our sewers."
posted by nthdegx at 7:27 AM on October 25, 2004

If you really want to put it down the drain, this guy has a good method.

"Many years ago my mother taught me a trick that really works to stop grease from coagulating in drain and city sewer lines. I knew that bacon grease and other greases turned into a hard slick mass once cooled so I was shocked one day as I saw my mother pour a large amount of bacon grease down our kitchen sink. What I didn't see is that minutes before she had squirted a generous amount of liquid dish soap into the skillet. She then added lots of hot water and mixed the grease with the soap. After pouring the solution into the sink, she let the hot water run for about one minute. Mom was using her training as a pharmacist to emulsify the grease."
posted by mrgavins at 7:34 AM on October 25, 2004

you can reuse cooking oil used for deep fryer. we used to just store it in the deep fryer (covered, of course). eventually the quality of the oil degrades and oil used for frying something with a strong odor/flavor (say, fish or onion rings) will impart flavor to other foods. it does eventually degrade and adding salt to it will cause that to happen more quickly. my 1960's edition of the joy of cooking has a little bit on the reuse and storage of oil used in deep-frying.

strain it after use, cover it and throw it it out when it starts to darken noticeably. i have always disposed of used deep-frying oil by either letting it harden and scooping it into the trash or pouring it into a coffee can while still liquid, letting it harden and throwing it into the trash.
posted by crush-onastick at 7:35 AM on October 25, 2004

It also depends on the oil you're using. If it's partially hydrogenated (like Crisco), over time, and reheating, it'll tend to pick up off flavors. (Alton Brown had a good explaination on this in the Good Eats episode I think was called "Fry Harder.")

I use corn oil for deep frying because it has a high smoke point. That smoke point will lower the more often it's re-used/heated.

If you don't have a deep fryer, you should strain it, preferably through a fine mesh or even a coffee filter in a funnel. and put it back into the container it came in, in a dark cupboard, and it can be reused several times, for up to 6 months. Iit will pick up flavors of the things you've cooked in it. This is called "nuance." Though, I don't know if I'd fry something sweet (like oreos) after I fried something savory (like fish), but the other way around might be ok.

When you do toss it, you should contain it ... I use old milk cartons for all my grease discards. Never pour it down the drain, unless you like dealing with clogged sinks.
posted by crunchland at 7:49 AM on October 25, 2004

You could just find a restaurant to make use of their grease dump.
posted by angry modem at 7:54 AM on October 25, 2004

You could use it to fuel your car.
posted by iconomy at 8:10 AM on October 25, 2004

please please please, do a favor to yourself, your arteries and your loved ones: do not reuse that shit at all cost. please. (and yeah, don't flush it, it's a killer for water pipes, as well)
posted by matteo at 8:10 AM on October 25, 2004

Around Thanksgiving you may be able to find grease filter devices in stores like K-Mart. The recent surge of interest in deep-frying turkeys has prompted a couple of companies to manufacture grease-filter pump thingies -- I saw one last year around this time.

The pump was electrically powered and looked kinda like a giant hand-blender. A hose came out the top, and you were supposed to put that in whatever container you planned on storing the oil in.

Dunno if they work, but I think it was only like $20 so I suppose you could give it a whirl.
posted by aramaic at 8:24 AM on October 25, 2004

posted by revgeorge at 9:08 AM on October 25, 2004

I strain the oil through a coffee filter into mason jars, and then cap 'em. The oil lasts forever and a day that way.

As long as the oil is liquid at room temperature, I can't see the harm in flushing it. It isn't going to suddenly solidify just because it's in a pipe.
posted by five fresh fish at 9:10 AM on October 25, 2004

As long as the oil is liquid at room temperature, I can't see the harm in flushing it. It isn't going to suddenly solidify just because it's in a pipe.

The oil will end up being the same temperature as your cold water is, as it also makes a similar magical underground journey. You might want to check if it solidifies at *that* temperature.
posted by shepd at 10:43 AM on October 25, 2004

You can also fill a plastic bag with newspapers and pour the slightly cooled fat/oil into it. The paper will absorb the grease, so it doesn't leak. My trash goes to a trash-to-energy incinerator, so this is recycling, of sorts. Putting it in the wastewater stream sounds environmentally unfriendly. It may not solidify immediately in the kitchen sink drain, but it will meet hair in the bend of a pipe, and aggravate any existing blockage.
posted by theora55 at 10:50 AM on October 25, 2004

Do not reuse oil that has been heated and then cooled. I'm not well versed in the related chemistry, but I believe you're "hydrogenating" and/or "oxidizing" the fat by exposing it to heat and air. The hydrogen, oxygen, or carbon (from cooking at high temps) molecules that are added create potentially dangerous compounds. These include acrolein and benzopyrene (very potent carcinogens), carbon (carcinogenic), and toxic "free radicals" or peroxides (strong oxidizing agents that can destroy cells, cell structure, and promote cancer). Hydrogenation (from the factory or in your FryDaddy) does increase the shelf life of oil (something about the added molecules inhibits bacteria growth) as well as increase the amount of "bad" cholesterol (LDL).

I'd be interested to hear more from a resident biochemist, but I know that it's very bad to reuse fats that have been heated to high temperatures.

As far as disposing used oil, I've always washed it down the drain with hot water and never had problems in either a sewer or septic-tank environment.
posted by maniactown at 11:26 AM on October 25, 2004

The hot water and detergent method is a terrible idea. The grease soon separates from the detergent and coats either your piping or the sewer later on. This just adds frigging detergent to the waste.

I get rid of mine by pouring it onto the absorbent mats we have for our dogs to pee and poop on.
posted by shoos at 12:05 PM on October 25, 2004

I inject it directly into my love handles. The track marks are unsightly but you can't beat the efficiency.
posted by damehex at 12:30 PM on October 25, 2004

We pour it into empty cans (tomato juice cans work great) and freeze it.

When we have a full can, we take it from the freezer on trash day and toss it into the bin at the curb.

No muss, no fuss.
posted by mr_crash_davis at 6:02 PM on October 25, 2004

maniactown: not much hydrogenating or oxidizing occurs when heating vegetable oil below the smoke point. Commercially, hydrogenated oil is produced with a catalyst (nickel/platinum/palladium metal) and hydrogen gas at a higher temp than you'd use for cooking. Oxidized oil is rancid oil and will be obvious by sniffing/tasting it. Oil that's been burnt should be tossed, however. Otherwise just don't use oil that smells or tastes off. Besides, someone who's very concerned about long term health isn't doing a lot of deep-frying anyway.
</lapsed biochemist>
posted by TimeFactor at 7:00 PM on October 25, 2004

My mom saves bacon grease in her fridge (throws hamburger grease) and uses it for lard. But this has nothing to do with deep-fryers.
posted by MrAnonymous at 7:19 PM on October 25, 2004

I pretty much do what crash does, although I don't deep-fry, so I pretty much use it for bacon grease and whatnot. I pour it into an empty tin can (soup cans are great), wait for it to solidify, then toss it in the trash. (But be careful -- if you live in a place where there are raccoons or other animals that like to get in the trash, they'll love old at.)
posted by Vidiot at 9:48 PM on October 25, 2004

errr...old fat, that is.
posted by Vidiot at 9:55 PM on October 25, 2004

Dammit TimeFactor, you beat me to it. How many biochemists do we have around here anyway? :-)

Putting on my chef's hat, reusing fat for deep frying is a very good thing. Small amounts of detergents form in the fat from frying, which allow it to have better contact with your wet food. This is why the first batch of anything you fry always comes out underbrowned. Even if you can't save all the oil, saving only a little until the next time helps a lot.
posted by TungstenChef at 2:53 AM on October 26, 2004