Why we cook food in oil

this video is sponsored by audible why does nearly every recipe start with dropping a film of oil into a pan ever wonder what had happened if you just didn't hey let's find out actually first let's do it the normal way just for the sake of comparison a little olive oil in a hot pan sprouts in and almost immediately you start to see this nice golden color emerging generations of people raised on boiled brussels sprouts grew to hate them and that's understandable you gotta brown them they're filled with starches and sugars and proteins that brown up real nice if you give them enough time and enough heat these took six minutes to get very brown and tender and quite tasty if i do say so myself now let's try to do the exact same thing again but with no oil are they going to stick to the pan without any oil in there not really not if you keep them moving here's our first bit of browning and check out how different that looks it's a patch of black with really clearly defined borders very different from the broad smudge of golden brown we got with oil there's a few little brown spots showing up on the cut sides but much smaller and more localized than the overall browning we got with oil and one other thing i noticed is that they're cooking very very slowly we're at six minutes now which is how long it took to cook the previous batch all the way through and these are still hard on the inside nowhere close to being tender after 11 minutes i'm giving up if i cook these any longer they're going to burn here they are side by side oiled sprouts are on the right and on the unoiled sprouts you can see how hard i have to push my fork in there they cooked for nearly twice as long and they are still not done also their flavor wasn't nearly as good so what's going on here well keeping the food from sticking to the pan is i think not the most important reason that we cook with oil oil or any kind of liquid fat has a much more significant role to play in that pan let's do it again with the thermal imaging camera i got some broccoli this time same basic deal that film of oil is serving as what they call a thermal interface the pan surface is flat and rigid the food is not so only teeny little bits of the food are actually making physical contact with the metal the oil essentially reaches up from the bottom of the pan and grabs hold of those bits that are floating just above the surface and because oil is a tremendously good conductor of heat energy from the pan is transmitted into more parts of the food than the pan itself could reach if i pull up this piece of broccoli you can see its whole face is really hot not just the parts in immediate contact with the metal and look at the nice brown color you get from that let's do this again with no oil in the pan and you can see that the heat on the broccoli is more localized to the few points making actual contact but also you can see that the overall heat of the food is just lower we simply aren't getting nearly as much energy in there and so this is going to take a lot longer and parts of the outside will probably be burned by the time the inside is tender now fat is not the only thermal interface that's available to us here in the kitchen right we also cook food all the time in water we boil food in water for the same reason we fry it in fat it's this heat conducting medium that can wrap itself all the way around the food and you could use water like oil in a saute just throw down a thin film of it and it will reach up and fill the gaps between the food and the pan surface conducting heat up into whatever you're cooking water might be the better dietary choice for those of us who maybe eat too many calories but it has some distinct disadvantages compared to oil in this context most cooking oils can get into the neighborhood of 400 fahrenheit 200 c before they even start breaking down into substances that aren't oil anymore water under normal atmospheric pressure can only get up to 212 fahrenheit c before it starts becoming something other than water namely steam it evaporates and leaves the pan that's bad for a saute because you'll have to keep replenishing the water but more significantly it's bad because browning reactions cannot happen at such a low temperature my yard reaction and caramelization both start around 330 fahrenheit 165c under normal terrestrial conditions water simply will never get that hot plus water isn't as viscous as fat so it's not going to coat the food as well as oil would therefore in order to use water is a really effective thermal interface you generally have to submerge food in it you got to boil it or you got to enclose the food in steam like you could put a lid on this pan right now and that's not a bad way to steam food if you don't have a steamer basket without a lid these are also just taking a very long time to cook i had them in there for 15 minutes and they're still not quite tender enough remember the ones we cooked in oil took six minutes so now you might be thinking yeah well i guess maybe you do need to coat vegetables in a little bit of oil in order to cook them in a pan vegetables have hardly any fat in them naturally what about something that does like meat why do you have to oil meat doesn't meat have enough fat inside itself to cook itself well let's try it i've got a little piece of sirloin steak here no extra fat at all on there just whatever is naturally in the meat and the first thing i notice it is stuck like glue to the pan meat is mostly water and protein and protein is particularly prone to sticking proteins form complexes with metal atoms at high temperatures they literally bond once the surface of the meat is really brown and rigid you can usually pull it off without tearing up the meat too much this is going to take some scraping unfortunately and yum look at that delicious golden crust i mean the meat is flat and pliable so it made much better contact with the pan surface than the vegetables did but you can still see some of that extreme contrast between the nearly blackened bits that touched the metal and the gray bits that seem to get hardly any heat at all there probably isn't enough fat in this meat to serve as a thermal interface or if there is not enough of it rendered out into the pan fast enough to coat the surface how exactly fats prevent food from sticking to the pan i'm not totally sure i've read several reputable scientific sources on the subject that don't seem to fully agree with each other it's certainly true that oils or all liquid fats will spread out across the pan and form some kind of a barrier between the proteins and the metal and because it's such an effective thermal interface fat cooks the surface of the meat a lot faster and more thoroughly and a really brown crust releases from the pan much more easily i also noticed that the whole steak is cooking much faster with oil in the pan and it tastes way better there's certainly some other chemical magic that happens between fats and other substances at high temperatures that create delicious flavors indeed we can observe a huge difference even if we take sticking totally out of the equation sirloin in a non-stick pan with no oil there's no sticking but nonetheless it's cooking really slowly and that crust is even worse at least with the stainless steel pan the meat stuck to the metal and that held it in contact with the heat on teflon there's nothing to stop big balloons of steam from pushing the meat up up and away from the hot pan and that's where you get those repulsive patches of gray even in a non-stick pan we still need oil to serve as a thermal interface and for its other flavor benefits now i bet some of you are thinking unfair test beef sirloin is a really lean cut of meat what if you were to cook a fattier cut without any supplemental oil indeed something like wagyu beef needs no extra fat at all in my experience how about this skin on chicken thigh i'm putting this into a dry and cold pan and then i'm gradually bringing in the heat this is the classic french way of cooking duck breast in a pan fat starts to render at relatively low temperatures so you give it a little head start to melt out some fat before the heat really gets going and cooking the meat by then you've got plenty of fat in the pan and the meat can fry itself works great with duck breast because duck breast has a huge layer of fat under the skin i thought it worked okay on this thigh not as good probably because there just isn't as much fat that skin has a bit of that weird mixture of overdone and underdone you get without sufficient thermal interface probably from the lack of fat at the very beginning of cooking not my favorite but of course all of this is subjective i mean the results are objective but whether or not you like them is totally subjective consider certain indian style breads that are cooked in a dry pan sorry this is not non-dough it's pizza dough just what i had available but this is a way that naan is often cooked dry pan no fat again highly localized browning or even blackening i'll do it again this time with oil in the pan and again generalized golden browning because of the thermal interface this one with no oil tastes like bread this one tastes like a donut i mean it's kind of awesome but this one does a better job of replicating the dry heat effects you get from an oven speaking of which do you really need to oil food before it goes in the oven let's find out i've got some mixed vegetables on this tray fatty beef roast and chicken thighs over here oil on one side of each pan only and i'll toss that around to get everything coated maybe a little foil snake will serve as some kind of a barrier between the oiled and unoiled sides into a 400 fahrenheit oven oiled food is on the right half an hour later the vegetables look done and boy that is not as big a difference as i was expecting both sides got about the same amount of color at least on top look underneath this parsnip was coated in oil and the side that touched the metal got beautiful golden brown i want to eat that over on the no oil side the part of the parsnip touching the metal has some of that same uneven coloration you get without the interface of the oil a mixture of burned and pale it's also kind of dry not as appetizing imho back over on the meat tray wow the oiled beef looks exactly the same as the unoiled beef there is an appreciable difference on the chicken though the oiled skin looks a little nicer than the unoiled skin i would guess that's because the skin served as a barrier preventing rendered fat from pushing up and settling on the surface whereas the open structure of this beef allowed for plenty of rendered fat to settle on the surface yep oil does not make as big of a difference in the oven as i would have guessed why i'm not totally sure i intended today's video to be more of a practical guide than a science explainer if you want more of the latter might i suggest our friend jay kenji lopez alts excellent book the food lab which you can listen to on audible the sponsor of this video my dad trained me in the art of making open-faced tuna melts on saturdays he also taught me a valuable lesson and how not to cut a block of frozen beef straight from the freezer into steaks a memorable afternoon that included the line kenji go get me the hammer don't worry the science gets considerably more sophisticated from there and i reckon i'm a slightly more sophisticated person thanks to audible i cannot sit with a book as often as i would like to but with audible i can listen even as i'm tearing down acoustical foam forts an audible membership gets you access to thousands of audiobook titles including all the latest bestsellers you also get unlimited access to the plus catalog which is all the bat catalog books ad free versions of podcasts and audible original programs like the words plus music series these are exclusive stories and performances from some of my favorite artists like elvis costello and new members can try audible free for 30 days visit audible.com slash adam ragusia or text adam ragusia to 500-500 that's all down in the description audible.com adam rogucia thank you audible and thank you fat it's not your fault i eat too much of you you're great in addition to being an excellent thermal interface and anti-stick agent you're also an essential nutrient and you facilitate the absorption of fat-soluble vitamins in my body that's probably the most important reason to cook in oil

Channel: Adam Ragusea

Views: 3,930,094

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Id: ktVSavCov9Y

Length: 12min 25sec (745 seconds)

Published: Mon Oct 25 2021