WEBVTT - Food Storage Mad Science, Part 2 0:00:03.040 --> 0:00:06.800 Welcome to Stuff to Blow Your Mind, production of iHeartRadio. 0:00:12.880 --> 0:00:15.760 Hello, and welcome to Stuff to Blow Your Mind. My 0:00:15.880 --> 0:00:19.080 name is Joe McCormick. My regular co host Rob Lamb 0:00:19.160 --> 0:00:21.280 is not with me today. He's going to be back, 0:00:21.320 --> 0:00:24.840 I think, for tomorrow's episode. So instead of Rob today, 0:00:24.880 --> 0:00:28.000 I am being joined once again by my friends and colleagues, 0:00:28.080 --> 0:00:34.360 Annie Reese and Lauren Vogelbaum, hosts of the food podcast Saver. Today, 0:00:34.360 --> 0:00:36.760 we're going to be recording part two of our series 0:00:36.800 --> 0:00:41.960 called Food Storage Mad Science, all about weird, spooky, and 0:00:42.000 --> 0:00:45.519 surprising things that can happen to leftovers and other foods 0:00:45.920 --> 0:00:48.920 during storage. If you haven't heard part one of this 0:00:49.000 --> 0:00:51.599 series that was Tuesday of this week, I'd recommend going 0:00:51.640 --> 0:00:54.080 back and listening to that one first, though I guess 0:00:54.400 --> 0:00:55.840 I don't know. The stuff we're talking about is not 0:00:55.920 --> 0:00:58.960 fully sequential, so if you'd rather listen to this one first, 0:00:59.000 --> 0:01:01.840 that that's okay too. But Annie and Lauren welcome back. 0:01:02.400 --> 0:01:04.720 Hi. Yeah, thanks for having us back. 0:01:04.959 --> 0:01:05.600 Yes, thank you. 0:01:06.640 --> 0:01:08.960 Okay. So, in part one of the series, we talked 0:01:08.959 --> 0:01:15.520 about two main food transformation phenomena. One was based on 0:01:15.600 --> 0:01:18.959 an anecdote that actually happened to me where a tray 0:01:19.160 --> 0:01:23.480 of leftover baked pasta eight holes in a sheet of 0:01:23.480 --> 0:01:26.280 aluminum foil while I had it stored in the refrigerator. 0:01:26.520 --> 0:01:28.200 We spent a while getting to the bottom of what 0:01:28.480 --> 0:01:32.959 exactly happened there and ended up discovering a pretty firm, 0:01:33.080 --> 0:01:36.880 but fascinating and bizarre answer. And then the other thing 0:01:36.920 --> 0:01:40.160 we talked about last time was the chemical process by 0:01:40.160 --> 0:01:44.560 which cooked or pickled garlic sometimes turns blue or jade 0:01:44.600 --> 0:01:47.840 green turns out. As long as this is not caused 0:01:47.880 --> 0:01:50.560 by mold, it is perfectly safe to eat, and in 0:01:50.640 --> 0:01:54.000 some food traditions, such as Chinese lava garlic, it's even 0:01:54.120 --> 0:01:57.200 an effect that people create on purpose. And we're back 0:01:57.240 --> 0:02:01.160 today to talk about more food transformations. So I think 0:02:01.160 --> 0:02:02.800 a major theme we're going to be looking at in 0:02:02.840 --> 0:02:09.280 this episode is the unexpected either explosion or combustion of 0:02:09.320 --> 0:02:12.320 food and drink. And if it's okay with y'all, I 0:02:12.360 --> 0:02:15.640 wanted to start by looking at a series of initially 0:02:15.760 --> 0:02:21.959 unexplained restaurant fires back around twenty nineteen. Yeah, we put 0:02:22.000 --> 0:02:24.960 on your fire investigator hats with shower, ok. 0:02:25.200 --> 0:02:25.720 Done. 0:02:26.080 --> 0:02:29.720 So here I'm relying on a few news articles to 0:02:29.720 --> 0:02:32.720 get the facts of the case, a July twelfth, twenty 0:02:32.800 --> 0:02:36.720 nineteen Wisconsin Public Radio article by Rob Mentzer, a July 0:02:36.840 --> 0:02:40.440 fifteenth article in The New York Times by Neil Victor, 0:02:40.919 --> 0:02:44.520 and a July sixteenth article for ABC News by Ela Torres. 0:02:45.440 --> 0:02:48.080 And so the story goes like this. In twenty nineteen, 0:02:48.639 --> 0:02:54.560 fire investigators in Wisconsin noticed a recent pattern of what 0:02:54.919 --> 0:03:01.119 appeared to be spontaneous combustion leading to fires in local restaurants. 0:03:01.400 --> 0:03:06.160 Primarily it was in places that served sushi. There were 0:03:06.360 --> 0:03:10.160 fires in two different sushi restaurants in the city of Madison, Wisconsin. 0:03:10.680 --> 0:03:12.880 And to get a little color on what happened here, 0:03:12.880 --> 0:03:15.919 I'm going to read from the ABC reporting quote. One 0:03:16.040 --> 0:03:19.200 blaze broke out at Sumo Steakhouse and Sushi Bar on 0:03:19.280 --> 0:03:23.800 April fifth, at around two thirty am. Firefighters entered the restaurant, 0:03:23.880 --> 0:03:26.359 threw a hatch on the roof, and found the kitchen 0:03:26.400 --> 0:03:29.600 in flames. A sprinkler managed to prevent the fire from 0:03:29.639 --> 0:03:32.920 further damaging the building, and the restaurant has since reopened. 0:03:33.280 --> 0:03:37.080 Another fire occurred on May tenth at the Madison restaurant 0:03:37.160 --> 0:03:41.080 to Kara, just before midnight. Firefighters were able to quickly 0:03:41.120 --> 0:03:44.560 extinguish the fire, though the damage was extensive to Kara 0:03:44.680 --> 0:03:47.960 remains closed and that was as of July twenty nineteen. Again, 0:03:49.120 --> 0:03:52.360 so fortunately no one was injured in these two incidents, 0:03:52.400 --> 0:03:55.920 but the damage was extensive, totaling more than five hundred 0:03:55.960 --> 0:03:59.600 and seventy five thousand dollars combined at the two restaurants. Yeah, 0:03:59.680 --> 0:04:03.280 so like serious fires, both of them happening in the 0:04:03.280 --> 0:04:06.040 middle of the night. That's kind of interesting, Like after 0:04:06.080 --> 0:04:08.880 the restaurants had closed, fires picked kicking up in the kitchen. 0:04:09.320 --> 0:04:12.160 So this is not from somebody actively cooking and setting 0:04:12.200 --> 0:04:16.400 fire to something. But this was not all. These two 0:04:16.400 --> 0:04:20.719 fires were linked to a pattern of similar restaurant fires 0:04:21.120 --> 0:04:23.480 across the state of Wisconsin. I think there were five 0:04:23.600 --> 0:04:26.719 total in Wisconsin, and then more across the rest of 0:04:26.720 --> 0:04:30.719 the United States, including in Saint Paul, Minnesota, and Ashburn, Virginia, 0:04:30.800 --> 0:04:35.000 and at least one fire in Canada. So big question 0:04:35.200 --> 0:04:39.320 what was causing these fires. Authorities got on the case, 0:04:39.560 --> 0:04:43.320 and these articles I mentioned all include interview material with 0:04:43.360 --> 0:04:46.599 a particular Wisconsin based fire investigator who I think was 0:04:46.640 --> 0:04:51.520 the lead investigator on this case, named Kara Nelson. Nelson 0:04:51.600 --> 0:04:55.160 coordinated with the Bureau of Alcohol, Tobacco, and Firearms to 0:04:55.320 --> 0:04:58.720 determine the cause of these blazes and ended up tracing 0:04:58.800 --> 0:05:04.880 them back to a form of what investigators call spontaneous combustion. Now, 0:05:04.880 --> 0:05:09.000 we could quibble about whether spontaneous combustion is a misleading 0:05:09.080 --> 0:05:12.240 term or not. I know, sometimes people trying to be 0:05:12.279 --> 0:05:15.880 scientifically accurate don't like that term because it could suggest 0:05:15.920 --> 0:05:19.080 that it's like without a cause somehow, you know, and 0:05:19.120 --> 0:05:22.400 they're they're usually various causes you can identify. In any case, 0:05:22.400 --> 0:05:26.520 I think it's definitely accurate to say surprise combustion. So 0:05:26.600 --> 0:05:31.080 a case of some surprise combustion which was occurring in 0:05:31.200 --> 0:05:34.920 all of these restaurants in the same food material, which 0:05:35.080 --> 0:05:40.520 was deep fried tempura flakes. Okay, y'all, y'all have feelings 0:05:40.560 --> 0:05:43.599 about tempora generally or deep fried tempora flakes. You know 0:05:43.720 --> 0:05:45.239 the crunch they put on the sushi rolls. 0:05:45.520 --> 0:05:46.800 Well, now I'm a little nervous. 0:05:48.440 --> 0:05:50.159 There's no I don't think you have anything to be 0:05:50.200 --> 0:05:54.240 afraid of from eating it. It's it's not an eating problem. 0:05:54.279 --> 0:05:57.039 It's a storage issue. We'll get in, we'll get to 0:05:57.040 --> 0:05:59.440 the bottom of it. But uh, but yeah, are you 0:05:59.480 --> 0:06:00.839 timpoora fans at least. 0:06:01.160 --> 0:06:06.159 No, No, I don't want fried in my sushi. It's 0:06:06.279 --> 0:06:08.560 I understand that it's a thing that some people enjoy. 0:06:08.920 --> 0:06:10.440 I'm there for raw fish. 0:06:10.920 --> 0:06:13.719 I agree with Lauren, But I like tempora as a 0:06:13.760 --> 0:06:14.360 separate thing. 0:06:14.640 --> 0:06:17.560 Yeah, yeah, okay, that's that's where I am. Annie. I'm 0:06:17.600 --> 0:06:19.960 not so big on the tempora in sushi, but I 0:06:20.000 --> 0:06:22.280 love like tempora shrimp or tempora vegetables. 0:06:22.560 --> 0:06:24.880 They're fine, They're often a little soggy for me. If 0:06:24.960 --> 0:06:29.039 I using using tempora tempora flakes specifically at home, it 0:06:29.080 --> 0:06:31.559 can be can be nice, like I enjoy a timpora batter, 0:06:31.720 --> 0:06:34.560 but you have to do it really care. I'm picky 0:06:34.839 --> 0:06:37.719 about my fried food. If I'm going to invest the 0:06:37.760 --> 0:06:42.000 caloric undertake of of fried food, I want to be 0:06:42.040 --> 0:06:43.000 real excited about it. 0:06:43.279 --> 0:06:45.800 Yeah. Okay, well I get that. But yeah, I appreciate 0:06:45.839 --> 0:06:49.560 at least tempora fried things on their own, but so 0:06:49.680 --> 0:06:54.440 Timpura deep fried tempora flakes are known in Japanese as 0:06:54.520 --> 0:06:59.680 aga dama or tinkasu, meaning tempora dregs, and as I 0:06:59.760 --> 0:07:01.960 think I just said, sometimes on menus you will see 0:07:02.000 --> 0:07:04.840 them described as crunch because it's mainly used to add 0:07:04.839 --> 0:07:09.640 a crispy textural element to certain sushi rolls. Timpura batter 0:07:09.920 --> 0:07:13.040 is typically made with some combination of wheat, flour and water, 0:07:13.200 --> 0:07:15.400 like a lot of batters, but you can have other 0:07:15.560 --> 0:07:18.160 things in there as well. Sometimes there will be other 0:07:18.320 --> 0:07:22.679 flowers or starches like corn starch. You might have baking powder, egg, 0:07:22.880 --> 0:07:25.880 so it's you know, it's nothing all that unusual as 0:07:25.880 --> 0:07:30.880 far as batter composition goes. Normally, when you're making tempura, 0:07:31.160 --> 0:07:33.840 you would dip your food in the batter and then 0:07:33.880 --> 0:07:35.960 deep fry it so that the batter forms a crispy 0:07:36.000 --> 0:07:38.960 coating on the fried food. But to make timpura crunch, 0:07:39.280 --> 0:07:42.360 you're just gonna be frying the batter itself. So you 0:07:42.440 --> 0:07:45.400 make these flakes by ladling a bunch of little drops 0:07:45.440 --> 0:07:47.520 of batter into the hot oil, and then you scoop 0:07:47.560 --> 0:07:50.040 them out with the strainer and deposit them into a 0:07:50.080 --> 0:07:55.000 storage vessel. And here's where the problem comes in. When 0:07:55.040 --> 0:07:59.440 these fried flakes are stored densely packed in a bowl 0:07:59.600 --> 0:08:03.360 or a pot, the heat cannot escape very well, and 0:08:03.560 --> 0:08:07.680 adding on that hot oily batter, when exposed to oxygen, 0:08:08.240 --> 0:08:13.440 can undergo a self accelerating chemical reaction that gives off 0:08:13.600 --> 0:08:17.240 even more heat, and if this heat cannot be removed 0:08:17.320 --> 0:08:21.280 fast enough, it just keeps building up until this fried 0:08:21.360 --> 0:08:24.040 food ignites, catches on fire, and then you have a 0:08:24.080 --> 0:08:28.520 kitchen fire. Karen Nelson, the fire investigator, quoted in the 0:08:28.560 --> 0:08:31.200 New York Times, says, quote, it is no different than 0:08:31.240 --> 0:08:34.360 the chemical reaction that causes more well known substances to 0:08:34.480 --> 0:08:38.199 spontaneously combust. It can happen in hay bales, it can 0:08:38.240 --> 0:08:42.439 happen in mulch piles, and apparently also in timpero flakes. 0:08:43.160 --> 0:08:45.680 So what does it look like when this happens. Well, 0:08:46.080 --> 0:08:49.559 the New York Times article includes security camera footage from 0:08:49.600 --> 0:08:52.800 inside one of these restaurants where the timpero flakes were 0:08:53.040 --> 0:08:55.800 made earlier in the day, in the afternoon and then 0:08:55.880 --> 0:08:59.240 left in a colander in the kitchen to cool. And 0:08:59.280 --> 0:09:02.080 you can see from the time stamps on the video, 0:09:02.559 --> 0:09:05.720 about six hours after they were first cooked, the flakes 0:09:05.840 --> 0:09:09.320 start smoking, and then something like ten hours after cooking, 0:09:09.559 --> 0:09:11.960 they actually catch on fire. And then the fire gets 0:09:12.000 --> 0:09:14.880 bigger and bigger, and then the walls are covered in flames. 0:09:15.160 --> 0:09:17.360 And then the part I found really scary is you 0:09:17.400 --> 0:09:19.920 see the sprinkler system come on and it starts dumping 0:09:19.960 --> 0:09:22.200 water all over the kitchen, but the fire does not 0:09:22.320 --> 0:09:25.840 immediately go out. It keeps flaming, kind of sputtering against 0:09:25.840 --> 0:09:28.319 the spray of water from above. I think the sprinklers 0:09:28.440 --> 0:09:31.800 can eventually douse the fires, you know, they cool them 0:09:31.800 --> 0:09:34.840 off and deprive them of oxygen. But for a while 0:09:34.880 --> 0:09:36.520 it looks like the fire is fighting back. 0:09:36.840 --> 0:09:40.720 Oh yeah, No, kitchens are terrifying, terrifying, yeah, for that reason. 0:09:40.840 --> 0:09:45.400 Yeah, yeah, So what exactly is this chemical reaction in 0:09:45.440 --> 0:09:47.840 the tempera batter that's causing it to act this way? 0:09:48.600 --> 0:09:51.760 Once again, like in the last episode with the aluminum 0:09:51.800 --> 0:09:54.679 anode in the Lasagna battery, we are looking at the 0:09:54.720 --> 0:09:59.640 process of oxidation at the molecular level. The fats and 0:09:59.720 --> 0:10:04.439 oil used in cooking are mainly composed of molecules called triglycerides, 0:10:04.840 --> 0:10:07.720 which in turn are made of a core lipid molecule 0:10:07.840 --> 0:10:13.480 called a glycerol bonded with three fatty acids. Triglycerides are 0:10:13.480 --> 0:10:15.480 found throughout nature. They're one of the main ways that 0:10:15.559 --> 0:10:19.480 animals and plants store energy for later use. So animals 0:10:19.559 --> 0:10:22.880 store these as fats in their adipose tissue, plants often 0:10:22.880 --> 0:10:25.840 store them in seeds or fruits. It's a very very 0:10:25.960 --> 0:10:28.920 efficient way to store a lot of energy in a 0:10:28.960 --> 0:10:32.160 small amount of matter, which is the main reason that. 0:10:32.200 --> 0:10:34.600 Also that fats are very calorically dense as a food, 0:10:34.679 --> 0:10:37.480 So you know, you're trying to store a lot of 0:10:37.520 --> 0:10:40.600 food in a small space and a small amount of weight. 0:10:40.679 --> 0:10:43.319 You want to have as many fats as you can. Also, 0:10:43.360 --> 0:10:47.079 that's delicious, right, and they taste good, yeah, for evolutionary 0:10:47.120 --> 0:10:49.280 reasons because their energy dense exactly. 0:10:49.480 --> 0:10:51.720 Yeah. 0:10:51.880 --> 0:10:56.720 So when oils made of triglycerides are exposed to oxygen, 0:10:56.840 --> 0:10:59.040 such as in the atmosphere, in the air around us, 0:10:59.400 --> 0:11:04.720 they undergo a chemical reaction called autooxidation. The oxidation reaction 0:11:04.920 --> 0:11:09.800 with the air the oxidation of triglycerides can sometimes result 0:11:09.960 --> 0:11:12.240 and it can do different things. It can sometimes result 0:11:12.280 --> 0:11:17.400 in polymerization, which is when small isolated lipid molecules called 0:11:17.520 --> 0:11:22.479 monomers bind together to form long chain molecules called polymers. 0:11:23.120 --> 0:11:25.760 And this is not the main process at play in 0:11:25.920 --> 0:11:28.280 Timpura flate combustion. But I did want to stick on 0:11:28.320 --> 0:11:30.280 this for a second because it relates to our conversation 0:11:30.320 --> 0:11:33.960 in the last episode about food reacting in interesting chemical 0:11:34.000 --> 0:11:37.760 ways with cooking pans. Polymerization is what happens when you 0:11:37.920 --> 0:11:40.880 season a cast iron or a carbon steel pan to 0:11:41.040 --> 0:11:44.839 create a rustproof and non stick surface. So you rub 0:11:44.840 --> 0:11:47.319 oil all over the iron and then you apply high 0:11:47.400 --> 0:11:51.160 heat to it. This heat helps oxidize the oil really fast, 0:11:51.400 --> 0:11:54.120 and it makes the oil molecules bond together into a 0:11:54.160 --> 0:11:57.520 big sheet of plastic y polymers coating the metal. And 0:11:57.600 --> 0:12:00.199 that does multiple things. It both protects the metal from 0:12:00.200 --> 0:12:03.319 exposure to oxygen, and it also makes the cooking surface 0:12:03.400 --> 0:12:07.520 more non stick. Are y'all very protective of cast iron 0:12:07.760 --> 0:12:09.839 and carbon steel cookware? I know, I know some people 0:12:09.840 --> 0:12:11.880 in their kitchens are like, you know, I don't let 0:12:11.920 --> 0:12:15.199 anybody use my cast iron pan. I'm afraid they might 0:12:15.320 --> 0:12:17.280 wash it the wrong way and get my seasoning off. 0:12:17.320 --> 0:12:19.920 Some people are very protective. My mom's like that. 0:12:20.760 --> 0:12:27.400 One time, I'm not great at it. And once before 0:12:27.640 --> 0:12:30.520 I knew more about cast iron pans, I was trying 0:12:30.559 --> 0:12:32.559 to help out a friend of mine who had made dinner, 0:12:33.480 --> 0:12:38.120 and I washed her cast iron pan, and she looked 0:12:38.120 --> 0:12:42.319 at me and was like, oh, my seasoning. You were 0:12:43.720 --> 0:12:46.240 like that because you are supposed to wash them. But 0:12:46.280 --> 0:12:48.479 I had really gone in for the scrub. 0:12:48.400 --> 0:12:51.479 Like, oh, dish detergent and steel wool. 0:12:52.040 --> 0:12:55.240 Yeah, and I still feel a lot of guilt about 0:12:55.280 --> 0:12:56.000 that whole thing. 0:12:56.520 --> 0:12:58.400 If you really go hard, you can you can do 0:12:58.440 --> 0:13:00.720 a lot of damage. But also I think people are 0:13:00.760 --> 0:13:03.640 a little overly precious about that. Like, you know, a 0:13:03.720 --> 0:13:05.840 quick wash with a little bit of soap, you usually 0:13:05.840 --> 0:13:08.000 still retain most of the seasoning. It's not going to 0:13:08.040 --> 0:13:10.719 be too bad. But yeah, if you really scrub at 0:13:10.760 --> 0:13:12.920 it and use a lot of detergent in there, it'll 0:13:12.920 --> 0:13:13.360 strip it. 0:13:13.640 --> 0:13:15.280 Yeah, I mean, even if you use a little bit 0:13:15.280 --> 0:13:17.839 of steel while on there, unless you know, if you're 0:13:17.880 --> 0:13:22.120 just using it to lightly scrape the surface not dig 0:13:22.280 --> 0:13:25.160 into it. Yeah, I don't know. I mean, you know. 0:13:25.559 --> 0:13:29.559 I but that being said, I do washvine with hot water, 0:13:29.960 --> 0:13:32.440 maybe a little bit of salt on a clean sponge. 0:13:32.559 --> 0:13:33.839 Oh yeah, I do that. 0:13:33.880 --> 0:13:36.160 Then I just yeah, I just rub, I'll oil into it, 0:13:36.200 --> 0:13:38.200 pop it in the toaster oven for like half an 0:13:38.240 --> 0:13:41.000 hour at two hundred go nice. 0:13:41.880 --> 0:13:44.720 I wish I could say I re season every time 0:13:44.760 --> 0:13:46.840 I use it. I know, they say, ideally that's what 0:13:46.920 --> 0:13:49.040 you do. Instead, I tend to have more like seasoning 0:13:49.160 --> 0:13:51.080 days when I have a day when I can set 0:13:51.080 --> 0:13:53.720 aside a few minutes to get out all of my 0:13:54.040 --> 0:13:57.760 all of my carbon steel and cast iron cookware, rub 0:13:57.800 --> 0:13:59.840 it all with oil, put it all in the same ovens. 0:14:00.000 --> 0:14:01.839 So that kind of saves energy if you do it 0:14:01.880 --> 0:14:04.640 all in the oven at the same time. But yeah, 0:14:05.080 --> 0:14:06.880 I try to take care of it, but I could 0:14:06.880 --> 0:14:07.920 take better care, I guess. 0:14:08.280 --> 0:14:10.439 I will say that the cast iron that I use 0:14:10.480 --> 0:14:14.480 in my home belongs to my roommate, and I'm more 0:14:14.600 --> 0:14:18.559 precious perhaps with her cast iron cookware than I would 0:14:18.600 --> 0:14:19.440 be with my own. 0:14:21.640 --> 0:14:25.280 So in addition to this where we're like baking oil 0:14:25.400 --> 0:14:28.360 onto our pans, you know, intentionally using very high heat 0:14:28.400 --> 0:14:31.120 to polymerize it, there are some special types of oil 0:14:31.200 --> 0:14:34.520 known as drying oils. Like this includes linseed oil or 0:14:34.560 --> 0:14:37.920 walnut oil, things like that that when exposed to oxygen, 0:14:38.040 --> 0:14:41.440 especially in the presence of heat, but when exposed to oxygen, 0:14:41.520 --> 0:14:46.440 naturally undergo oxidation and polymerization as they dry or people 0:14:46.440 --> 0:14:50.280 sometimes call this curing maybe drying. Normally, when we think 0:14:50.280 --> 0:14:53.960 about liquids drying, we're imagining water based liquids or maybe 0:14:54.040 --> 0:14:57.240 alcohol or something which dry by evaporating into the air. 0:14:57.360 --> 0:15:01.080 Of course, oils don't evaporate. When these oils dry, we're 0:15:01.200 --> 0:15:04.360 typically talking about them oxidizing in reaction with the air 0:15:04.680 --> 0:15:07.720 and then forming a hard polymer. So drying oils are 0:15:07.720 --> 0:15:10.840 often used as the base lipid and substances like paint. 0:15:11.480 --> 0:15:13.640 This is also why you can rub some walnut oil 0:15:13.800 --> 0:15:16.880 into like a hardwood floor if it's getting a little 0:15:16.920 --> 0:15:20.160 patchy in places, and it will help help reseal the floor. 0:15:20.600 --> 0:15:24.040 Yes, exactly totally. So these they have the sealent quality 0:15:24.520 --> 0:15:28.440 because they form the polymerization surface. But a different oxidation 0:15:28.520 --> 0:15:30.800 process is more important to consider in the case of 0:15:30.880 --> 0:15:33.960 food and also in the case of fires, and that 0:15:34.120 --> 0:15:38.880 is decomposition. This is when oils exposed to oxygen start 0:15:38.920 --> 0:15:43.120 to break down at the molecular level. So triglycerides react 0:15:43.120 --> 0:15:48.560 with oxygen to form these unstable molecules called hydroperoxides, and 0:15:48.600 --> 0:15:53.160 then the hydroperoxides, because they are unstable, break apart into smaller, 0:15:53.280 --> 0:15:56.800 volatile molecules of many different kinds. You get short chain 0:15:56.840 --> 0:16:02.280 fatty acids, aldehydes, esters ketone, and as a side note, 0:16:02.280 --> 0:16:06.080 a lot of these breakdown products smell and taste bad. 0:16:06.760 --> 0:16:10.640 The oxidation of cooking oil is the main cause of 0:16:10.920 --> 0:16:14.920 oil ransidity. So when oil is old or it's been 0:16:14.960 --> 0:16:17.680 sitting too long in the fryer and starts to taste bad, 0:16:18.000 --> 0:16:20.440 that usually means that a lot of these oxidation by 0:16:20.520 --> 0:16:23.560 products are mixed in with the oil and they produce 0:16:23.640 --> 0:16:28.680 these unpleasant, sometimes bitter or metallic flavors and aromas. But then, 0:16:28.720 --> 0:16:30.840 on the other hand, I do believe that some of 0:16:30.880 --> 0:16:35.920 the pleasant aromas and flavors we associate with fried foods 0:16:36.280 --> 0:16:39.840 also come from some oil oxidation and breakdown products like 0:16:39.840 --> 0:16:43.040 that kind of you know, festival food, fried food smell. 0:16:43.440 --> 0:16:45.920 I think that that's some of that too. But if 0:16:45.920 --> 0:16:48.120 you get too much oxidation, I think that is when 0:16:48.160 --> 0:16:51.880 things start to be overwhelmingly unpleasant. Ever, you know, you 0:16:51.920 --> 0:16:54.720 smell the oil in the bottle and something just smells 0:16:54.720 --> 0:16:56.040 like metal or something m. 0:16:56.240 --> 0:16:59.040 Mmm, or if you come home from a dive bar 0:16:59.120 --> 0:17:01.400 and your shirt is just you're like, oh, this is 0:17:01.520 --> 0:17:02.600 bad fryar smell. 0:17:02.800 --> 0:17:03.600 Oh why. 0:17:05.080 --> 0:17:06.240 I ate those fries? 0:17:06.320 --> 0:17:13.360 Oh no, yeah, But okay, So anybody with some experience 0:17:13.359 --> 0:17:15.359 in the kitchen is going to be familiar with these 0:17:15.440 --> 0:17:18.440 cases of oil oxidation, like oil ransidity. If the oil 0:17:18.520 --> 0:17:21.240 is old enough it's gonna smell weird, taste bad or 0:17:21.520 --> 0:17:25.119 seasoning cast iron pans and stuff. But how does oil 0:17:25.200 --> 0:17:30.000 reacting with oxygen actually result in a fire. So, the 0:17:30.040 --> 0:17:35.680 autooxidation of unsaturated fats is what's called an exothermic reaction, 0:17:35.920 --> 0:17:40.320 meaning the chemical reaction releases heat. It takes heat to 0:17:40.400 --> 0:17:44.600 get going, but it also releases more heat when it happens. 0:17:45.200 --> 0:17:49.280 So if a bunch of oily material like oily fried 0:17:49.320 --> 0:17:52.680 bits of batter or oily rags another common example here, 0:17:53.200 --> 0:17:56.160 if a bunch of that material is kept bunched up 0:17:56.240 --> 0:18:00.439 tightly in space somewhere, the heat from that exothermic reaction 0:18:01.119 --> 0:18:04.560 gets the oil around it hotter, which makes the oxidation 0:18:04.640 --> 0:18:07.720 happen faster in the surrounding oil, and then it releases 0:18:07.760 --> 0:18:10.320 more heat, and the heat can't escape because it's all 0:18:10.320 --> 0:18:13.560 packed together in a bowl, and you get runaway thermal 0:18:13.720 --> 0:18:17.679 escalation until it starts smoking and then catches fire. So, 0:18:17.840 --> 0:18:21.400 coming back to the sushi restaurant fires, this article by 0:18:21.400 --> 0:18:26.439 Wisconsin Public Radio describes some tests that fire investigators use 0:18:26.520 --> 0:18:30.600 to confirm their theory about the spontaneous combustion of timpura batter. 0:18:31.000 --> 0:18:34.000 One of the restaurants agreed to make a test batch, 0:18:34.320 --> 0:18:38.040 and according to Karen Nelson, the investigator from Madison, when 0:18:38.080 --> 0:18:40.560 they measured the temperature in the middle of the bowl 0:18:40.600 --> 0:18:42.879 of fried batter, it had reached two hundred and seventy 0:18:42.880 --> 0:18:46.560 seven degrees. The article does not say fahrenheit or celsius. 0:18:46.800 --> 0:18:49.320 I think this has to be fahrenheit because oily batter 0:18:49.359 --> 0:18:52.160 at two hundred and seventy seven celsius would probably already 0:18:52.200 --> 0:18:52.800 be on fire. 0:18:53.160 --> 0:18:56.680 Yes, no, no, yeah, yeah, that sounds like a very 0:18:56.680 --> 0:18:58.520 bad situation, but. 0:18:58.560 --> 0:19:02.560 That's still I mean, even fahrenheit, that's hot inside. That's 0:19:02.600 --> 0:19:05.040 start starting with a lot of heat packed in there. 0:19:05.080 --> 0:19:07.359 And then if you just leave it sitting, you would 0:19:07.400 --> 0:19:09.960 expect and naturally, when you leave hot things sitting, they 0:19:09.960 --> 0:19:12.880 cool off over time. But this one, the heat starts 0:19:12.960 --> 0:19:16.679 triggering this rapid oxidation reaction with the air and it 0:19:16.680 --> 0:19:19.440 gets hotter instead of cooling off, and it just gets 0:19:19.480 --> 0:19:22.760 hotter and hotter until you have a fire. In Karen 0:19:22.800 --> 0:19:26.000 Nelson's words quote, as they deep fried in batches, they 0:19:26.000 --> 0:19:28.560 put it into a colander or mesh strainer in batches, 0:19:28.600 --> 0:19:31.600 so they're basically adding heat every time. So the heat 0:19:31.640 --> 0:19:35.040 builds and builds once it hits ignition temperature, that's when 0:19:35.080 --> 0:19:39.360 a fire occurs. Now, one question I had about this 0:19:40.000 --> 0:19:44.639 is why is it that oily rags or fried batter 0:19:45.240 --> 0:19:50.440 can spontaneously or again, spontaneous combustion is used throughout this reporting, 0:19:50.520 --> 0:19:53.439 so maybe to put aside spontaneous, why is it that 0:19:53.520 --> 0:19:58.359 oily rags or fried batter can go under surprise combustion 0:19:58.840 --> 0:20:02.440 but a massive oil on its own does not, Because 0:20:02.440 --> 0:20:05.000 it is the oil that's oxidizing reacting with the air. 0:20:05.560 --> 0:20:08.520 And I believe the answer here is mainly about surface area. 0:20:09.119 --> 0:20:13.320 Oily rags or oily craggy bits of fried food expose 0:20:13.680 --> 0:20:16.720 more oil to the air all at once than you 0:20:16.720 --> 0:20:19.919 would be able to with just a volume of oil 0:20:20.080 --> 0:20:23.119 stored on its own. When oil is in a container, 0:20:23.600 --> 0:20:26.280 most of the oil is submerged and only the top 0:20:26.320 --> 0:20:29.040 surface is exposed to the air. And then on top 0:20:29.080 --> 0:20:33.080 of that, oily rags or timpuraflakes also accelerate the reaction 0:20:33.200 --> 0:20:37.000 because the air pockets inside these masses of rags or 0:20:37.040 --> 0:20:40.800 food provide insulation and they keep the heat trapped inside 0:20:40.840 --> 0:20:41.480 for longer. 0:20:42.720 --> 0:20:45.240 I wonder if you also have in there the factor 0:20:45.320 --> 0:20:48.800 of some kind of combustive material that gets the whole 0:20:48.840 --> 0:20:51.199 process kind of started once it gets hot enough, like 0:20:51.200 --> 0:20:53.480 you've got the flour or you've got cotton in the 0:20:53.520 --> 0:20:56.680 case of rags. I mean there have been without oils 0:20:56.720 --> 0:20:59.159 particularly present, there have been all kinds of fires and 0:20:59.280 --> 0:21:01.560 in flower facts over the course of history. 0:21:01.680 --> 0:21:04.359 So yes, yeah, grain fires can be a big thing, 0:21:04.440 --> 0:21:07.760 especially when the grain is I know, the big thing. 0:21:07.800 --> 0:21:11.280 There is a lot of powdered foods can cause fires 0:21:11.320 --> 0:21:13.720 when they're dispersed in the air. So like this can 0:21:13.760 --> 0:21:16.399 happen with flour or any kind of grain. It can 0:21:16.440 --> 0:21:20.639 happen with powdered milk if you have you know, dairies 0:21:20.680 --> 0:21:24.680 and creameries, they can have powdered milk fires. So yeah, 0:21:24.840 --> 0:21:27.440 that is certainly a risk too. So it probably does 0:21:27.520 --> 0:21:30.919 not hurt that the the thing that's being fried also 0:21:31.119 --> 0:21:34.000 is a pretty ready fuel source. You know, it's not 0:21:34.119 --> 0:21:36.920 like something that won't burn being coated in oil. 0:21:37.359 --> 0:21:40.920 We should be making flakes of meat for sushi. 0:21:41.720 --> 0:21:44.880 But so okay, let's say that maybe I'm a person 0:21:44.920 --> 0:21:47.000 who loves tempera crunch, and I want to make temper 0:21:47.040 --> 0:21:49.200 a crunch, but I don't want to start a fire 0:21:49.200 --> 0:21:53.359 in my kitchen. What are some ways around this? One is, 0:21:53.480 --> 0:21:57.359 if you're making fried tempera batter or any similar fried substance, 0:21:57.840 --> 0:22:01.840 don't store it in a densely packed way right after 0:22:01.880 --> 0:22:04.200 you cook it. So don't dump it into a bowl 0:22:04.640 --> 0:22:07.560 or anywhere that it is densely piled up on itself. 0:22:07.840 --> 0:22:09.840 Spread it out on a baking sheet or some of 0:22:09.840 --> 0:22:13.480 their surface where it can cool more efficiently. Another piece 0:22:13.520 --> 0:22:15.719 of advice they give is don't make a batch of 0:22:15.760 --> 0:22:18.040 fried batter and then like at the end of the 0:22:18.160 --> 0:22:21.159 night and then leave it unattended overnight. That is what 0:22:21.240 --> 0:22:25.439 happened in some of these cases. These articles recommend that 0:22:25.680 --> 0:22:28.720 restaurant owners make fried tempura batter in the morning so 0:22:28.760 --> 0:22:31.280 that you will be around in the kitchen to observe 0:22:31.320 --> 0:22:34.719 it during the danger window, which these articles suggest is 0:22:34.760 --> 0:22:37.359