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Apr 29, 2010 11:58 AM

ATTENTION DEEP FRYING EXPERTS! The Zen of Maintaining Proper Oil Temperature

I followed the recipe from Cooks Illustrated for Korean fried chicken and the results were PHENOMENAL. Tastes just like KyoChon.

Here a link to the recipe-- may require a subscription

But here's the thing... the recipe was extremely specific about keeping the temperature of the oil at 350 degrees for proper results. I have a old gas range and a 7.25 qt round Le Creuset, which I emptied about 2 inches of canola oil in to. The oil got to 350 and higher, but as I added the chicken to the pot the temperature came down and never recovered. The recipe says to add 1.75 lbs of battered chicken wings at a time (one piece at a time) but I found that when I added more than 5 or 6 wings the temperature dropped to about 330 and could not recover.

The question is somewhat moot, because even at 330 the results were great. But it does bring up the question... how does one maintain a proper frying temperature? Is my gas range just hopelessly underpowered? I kept trying to adapt for the temp drop by waiting until the oil got to 360 before adding chicken. (I was testing the oil temp with an instant read Thermapen, so the temperatures should have been pretty accurate.


Lastly, what is the best way to filter and reuse the oil? At what point should I no longer reuse the oil?

Thanks Fry Hounds!

Mr Taster

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  1. Unfortunately I couldn't check out your recipe, no subscription to CI.

    Keeping oil at a steady frying temp is a issue for home stove tops. Restaurants use big btu fryers that recover quickly; we home cooks don't always have that option. Do not despair.

    What I can suggest is to fry less at a time, which I believe you tried. It's all about the btu's and unfortunately it sounds like you don't have 'em. Sometimes it's quantity of oil as well, a large quantity of oil at the proper temp will cook more pieces of whatever without the loss of temp, then a smaller quantity of oil. Was your chicken cold or at room temp? Food temperature effects low btu situations as well. What type of oil are you using? That doesn't matter much for temp control, I'm just curious. Refined peanut or grapeseed oil are the best for high temp deep frying. Sometimes leaving a lid on the fryer helps to keep in the heat.

    So, cook less wings at a time in larger quantiites of oil. That's my best advice and also what I do, except for French fries. Because they're smaller, the temp seems to recover pretty quickly when I'm frying them on my gas range.

    Filter your cooled oil into a dedicated container, preferably glass, through a coffee filter or paper towel. Depending upon the application, the oil can be reused at least a few times, but it's best not to mix oils that certain items have been fried in, to avoid flavor contamination, i.e. you wouldn't use fish frying oil for French fires. You'll know when the oil is shot, the oil color will have darkens quite a lot, and it will start to foam up (foam, not bubble) when you fry something.

    5 Replies
    1. re: bushwickgirl

      Thanks for all this info, bushwickgirl

      Yes, it does appear that I am bumping my head (yet again!) against the limitations imposed on me by a crippled home kitchen. Since I have been upping my cooking game over the last few years, I've noticed this has been a recurring theme in my life. It's easy to fix when it's a cheap frying pan that needs upgrading to a fully clad pan. Not so easy when you rent an apartment and the landlord has no interest in converting it into a professional kitchen for you!

      The chicken I used was cooler than room temp, but not straight out of the fridge. I can see how that would help. Of course by the time I added the chicken for the second fry, the chicken was warm and I experienced the same problem with the oil not being able to recover temp.

      CI's recipes are generally *extremely* accurate and detailed. If they tell you to add 1/2 of the 3.5 lbs of wings into the fryer, you can be assured that someone in their test kitchen did this several times successfully before committing it to paper. It always bothers me when my home kitchen experiences don't match up with theirs, because it generally means that there's something wrong with my stuff (as opposed to theirs). I followed the directions exactly-- used 7.25 quart Le Creuset, 2 inches of veg oil (I used canola, peanut too expensive), heated to 350 degrees on medium high heat.

      So after drying the wings, seasoning with salt and pepper, dredging in sifted cornstarch, and a final dredge in cornstarch/salt/water batter, the recipe does in fact tell you to add half of the chicken-- a full 1.75 lbs, one piece at a time, to the pot of 350 degree oil. I had faith that it would work, but my oil just couldn't take it.

      So yeah, it sounds like you're right... other than installing a stronger gas range, my options seem to be frying less chicken at a time. I already had to break it down into 3-4 batches, and even then I experienced a temp drop to 320-330. If I had maintained a full 350 the whole time, what would the difference have been?

      Mr Taster

      1. re: bushwickgirl

        hey! actually my try was oppsoite. i made duplicated ad hoc buttermilk fried chicken with canola oil rather than peanut oil. when i put the two pices of chikcen into bit less than 2 liters of the oil in 5 quart stainless pot, oil temps suddnly spiked up quite fast and a lot.
        i did this on gas stove top. do you know why my canola oil temps was otherwise?

        1. re: hae young

          The type of oil doesn't matter (with respect to this phenomenon) - this happens (temp shoots up) with everything to a certain degree, but especially with anything that is very wet. It has to do with the surface water superheating in the initial minutes - all the steam is released and the amount of it trapped in the oil has an additive effect. The key is that it should start to go down almost immediately, as the surface seals up, and then the effect of the larger thermal mass of your material (chicken) being at a lower temp will start to bring your temp down. You must compensate by turning the heat up at that point - but being careful not to overshoot.

          To avoid the superheating - bubbling and steaming - pat your material dry before dropping it in the oil. That's the best way to get a nice crispy coating. Batter will be inevitably wet, but with the right material at the right temps, will quickly form a skin and let the moisture stay inside.

          1. re: applehome

            i guess the very moisture is due to 12 hours of lemon brine.

            1. re: hae young

              But you can still pat the item dry on the outside. The beauty of dff is that it seals the moisture in.

      2. "The question is somewhat moot, because even at 330 the results were great."

        When you win the lottery do you also worry that the State will pay you in 20s, instead of 100s?

        If your wings turned out great, why worry about how and why you cannot maintain constant oil temp.

        I would focus more on the fact that you made "great" wings! Which by itself is something that should be lauded and celebrated and not fussed over b/c (gasp!) your oil temp deviated from 350F.


        (P.S. I echo everything that bushwickgirl said above. It's nearly impossible to maintain a constant oil temp with most home setups. And, yes, adding less at a time will help keep your oil temp within a more narrow constant range.)

        2 Replies
        1. re: ipsedixit

          I know, but this is not just about one batch of wings. I do tend to be a fusspot about following directions on topics which I know little about because a bigger part of the doing is learning. And although the wings were great, I am still left wondering... "Would they have been even better at 350?" Then comes the obsessive spiral of doing everything I can to find a rig that will allow me to do just that...

          1. re: Mr Taster

            It's difficult to know what type of deep frying equipment CI used in their kitchen for testing. My assumption is they have commercial ranges with big btu's and possibly a deep fryer. If that's the case, their method is not really a fair comparison to what home cooks can produce. From my experience with their recipes, though, CI is very careful in detailing accurate instructions, ingredient amounts and techniques; their wonderful reputation depends on that.

            330* is not a bad deep frying temp. At 350* things will be crispier, in the sense that they fry at a hotter temp, and take less time to cook. At 330*, you'll get similar results, with just a bit longer frying time. I routinely blanch French fries at 325* then refried to crisp at 350*. So if that's what you have, it's not at all bad.

            If you're happy with the wings outcome, and admittedly you are, then that's cool. Please don't obsess over this, if there's not much you can do about it at this point in time. If you find a way to improve the oil temp situation in the future, and you may, that's great, but know that what you're currently doing is not too shabby.

        2. Most restaurants set their fryer temps above 350F. degrees to allow for it to drop when food is added thereby keeping the heat more consistent. For example, the place I worked at kept the fryer temp at 380F. You can try increasing your temperature at home, but use an oil with a higher smoke point as suggested by Bushwickgirl; it won't work with other oils and will burn your food. I wouldn't go as far as 380F. using anything other than a deep fryer., but you could go say, 365F-370F. degrees with a chicken fryer or dutch oven

          1. I'm not going to say much because the ever-so-talented bushwickgirl said it all...

            I will underscore the fact that Mr. Taster's got the right idea... there is, indeed, a *huge* difference in results with just 10-20 degrees' difference in temp, when frying.

            It's too bad that Mr. Taster's stove is woefully under-powered. The use of the nice, heavy Le Creuset is a good "buffer"... it keeps a little heat so will help keep temps from going down too far... Cast Iron is great, too. Years ago I used an old cast iron dutch oven to do deep-fry (immersion; deeper than the 2" the OP used to cook the wings).

            There was a post here a couple of months back that addressed the old-fashioned electric skillets... they had a temperature control that was automatic... and I remember deep-frying chicken in the one my mom had (it was a Kenmore). But sadly the dinky element will indeed not give you the fire you need.

            I also take exception to the poster, above, who claims that restaurants routinely go above 350... I would never allow my fry-cook to sustain 380 degrees; once you go above 350, the oil starts breaking down very rapidly (turning dark amber and "foaming" the way bushwickgirl describes -- foamy oil will, indeed, cook your food but will also render it saturated and off-tasting).

            We have two Pitco Fryalators at our restaurant... One's kept as low as 325 and the other will range from 350-360 but no higher. Of course, I can dump a few pounds of fridge-temperature chicken wings in the hi-temp one without diminishing the temperature of the oil at all, for two reasons: the sheer volume of oil is such that it stays hot, and also these things fire at 140,000-150,000 btus... when the gas turns on, the heat generated is sweltering! If you go with wings that are cool inside I find they come out juicier. But again, if you're doing it on a home stove-top the cool wings *may* impact the heat so negatively that you'll get some of the saturation that occurs at low-temp.

            Re: oil. I use pure soy oil and always have. And my Chinese chef doesn't actually filter the oil; we place it in a huge stock-pot and let the particles precipitate to the bottom; we re-use 3/4 of the oil and throw out the dark-amber sludge that remains. It takes no effort; just time (we let it precipitate at room temperature for about eight hours).

            1. Deep fat frying, aka "French frying," is a problem for home cooks, especially today. Sounds to me as if your problem is a really good pot for deep frying and a really wimpy stove. Holding the temperature when you add cold food to hot oil has a ratio to it: The more cold food you add, the greater the temperature drop. The wimpier your heat source, the more difficult it is to regain what you've lost, and in some instances it's practially impossible. Sounds to me like you're sitting in that chair.

              I would guess that you're not jumping up and down with joy thinking of the expense of replacing your stove, but just in case you are, go induction. MUCH faster heat recovery than any other cooking method. But short of that, my suggestion is that you go to garage sales and pawn shops looking for an OLD Sunbearm cooker deep fryer. Here's a picture of one for sale on eBay that is identical to mine: The advantage of it is that it has an extremely thick cast aluminum liner that helps retain heat when cold food is added to hot oil or liquid. The temperature range runs from a very low simmer to a whoppingly hot 425F. (Do NOT crank it up that high for deep frying!) It works great as a slow cooker or a deep fat fryer. The ONLY problem is that it's a pain in the butt to clean, but hey, no free lunch. I also have a brand spanking new modern French fryer with the grease filter and all that good stuff, but it just doesn't hold a candle to the Sunbeam when it comes to performance, so it collects dust on the shelf.

              Sometimes old really is better! '-)

              3 Replies
              1. re: Caroline1

                You are absolutely correct C1, I had one of these given to me once upon a time and I couldn't agree more "The advantage of it is that it has an extremely thick cast aluminum liner that helps retain heat when cold food is added to hot oil or liquid. "
                I used this baby often, long story short, a divorce and he got the cooker. Anyway, looking for another manual, I found the owners manual. The instruction for fried chicken read to fry at 375F in preheated shortening, & to fry large pieces with like & small etc.
                Sure do miss that pot.

                1. re: chef chicklet

                  They have several on eBay. I've lost my fryer basket, so I'm thinking about one for a back-up and then I'll have one basket for two pots! '-)

                  1. re: Caroline1

                    Oh no!
                    Thanks, I will take a look around on eBay. I also thought that I'd check out my favorite thrift shop, I often find really great stuff in there, sometimes completely untouched or barely used. Love it when that happens.