Which type of oil/fat should I use for deep frying?

For the very best tasting fries, onion rings and battered fish are fried in fat made from rendered beef fat. When I was a cook we rendered down a thousand pounds of beef fat a week, it took days to do. But it made the very best tasting savory deep fried foods. The burning temperature is lowish, so food needs to be cooked at 325 and changed more often. It's not good for things like doughnuts.

I'm not a fan of Canola, I find it often has a taste which I don't like. I don't use peanut mostly due to habit, too many people I've run into with allergies. I can't find rendered beef fat and I'm not going to render it at home.

At home I use a mixture of Sunflower and lard, about 1 part to 3 parts. The sunflower oil makes it easier to handle when filtering through a very fine mesh sieve (more liquid at a lower temperature) after use, then I put it in an old olive oil can which I refrigerate between uses. I leave out overnight before I use it then warm in hot water to pour it out. I don't usually use more then once a month. The more crumbs and batter bits you filter out the longer the fat will remain good. So filter, and don't pour the last bit into the can.

Refrigerated the oil mix doesn't go bad before it becomes no good to use. I get well over a years use. I love sunflower oil, it has almost no taste at all and a high smoke temp. It is pricey.

The best thing to fry, or deep fry with is actually old-fashioned lard. Yes, it is full of saturated fats, but it withstands very high temperatures. Olive oil does not have a very high heating point, and once again, the polyunsaturated fats are transformed. I'm not saying to eat something fried or deep fried in lard every day, but once in a while, and if you want it to be good, use lard.

First and foremost choose a frying medium with a high enough smoke point. You don't want to risk your oil deteriorating before it reaches the temperature you want it to be at. Now, if you'd like to use an oil, I say go for a something neutral in flavor: canola or peanut. If you are looking at using an animal fat, lard from Pigs is the most common. If rendered properly it shouldn't affect the flavor of your foods in an overly negative way.

If it's solid at room temperature, then it's either saturated fat or largely trans-unsaturated fat.

The former is what humans have used for cooking for centuries and is biologically safe. It is also what I would personally recommend.

The latter is from a manufactured process and was originally created so as to be solid at room temperature. (There is considerable dispute about whether we should be even using this kind of fat to cook with.)

Both will return to solid after cooking.

I have found that mixing corn oil with equal parts Crisco make an oil that can be heated relatively high, with little to very little taste.

I recently learned of an oil called " rice bran oil ". This oil has a smokepoint of 490 degrees. Since most commercial places I've contacted say foods are best fried at 350-375, this makes very good sense. I was told this frying temp keeps the food from being soggy. It cost about the same as peanut oil but has a higher smokepoint. You can buy it in bulk and it's cheaper. I got mine from Riceland Foods in Arkansas.

In the interests of safety, most modern deep fat fryers say NO lard, butter, etc. (hard fats). The manufacturers don't say why but I've heard many people conjecture that lard heats up, smokes, maybe burns when exposed to fairly high temperatures (over 370F. or 185C.). My theory is that the heating coils on the deep fat fryer overheat the lard if it is used in its hard form.

We have real lard (from a real pig raised on a real farm -- not a huge farm where pigs lead a short and brutal life). Then we rendered it ourselves which is not hard at all.

We are just about to try cooking french fries (British, chips) in our new deep fat fryer. We have melted the lard, strained it and poured it in, as one would with canola oil, etc.

Wish us luck, please. I'll try to report back on this scary adventure in cooking!

UPDATE: Okay, that didn't work too well. The fries never did brown even after 15 minutes at 320F. and then 12 minutes at 370F. (ordinarily 5 to 7 minutes at the lower, cooled, then 2 minutes at the higher). Cooked but not browned. So I threw a few in a fry pan and burned them a bit. Oh dear. Did I mention we are at 3000 feet above sea level? This makes a bit of a difference in cooking. My friend (bless her heart) said she loves blond french fries and ate them up. I was not quite so pleased!

Since I find myself unable to source certifiably natural lard, when I do fry, I use coconut oil. Coconuts are in fact, mostly saturated fat and hence more stable, having a fairly high heat tolerance. Again, if I could get my hands on quality lard, I'd use it when needed. I use butter for pan frying.

Hard fats such as lard or dripping I find give things much more flavour.

I normally go for a relatively neutral oil such as groundnut or sunflower.

What you are cooking will also effect what you want to use, as different fats have different smoke points and it may be that what you are trying to fry requires more heat than the fat can handle safely.

My mother used to make delicious chips. She bought raw beef suet from the butcher very cheaply. She heated it gently in a heavy pan (with lid) until the the fat had come out. This is called rendering. The liquid fat (called dripping) was then poured into a pyrex bowl and cooled. This is a very hard fat when cold. It can be used for some pastry recipes. She used a chip pan - a large heavy pot with a wire basket and a lid. The solid dripping was added to the chip pan, food was cooked and afterwards everything was allowed to cool and the dripping sat in the pan until next time. Now people think dripping is unhealthy and chip pans are dangerous but the flavour was wonderful. Lard is pig fat. We didn't use it much.