WEBVTT - Stickiness, Part 1 0:00:03.040 --> 0:00:07.120 Welcome to Stuff to Blow Your Mind, a production of iHeartRadio. 0:00:12.920 --> 0:00:14.760 Hey you welcome to Stuff to Blow your Mind. My 0:00:14.880 --> 0:00:16.120 name is Robert Lamb. 0:00:16.120 --> 0:00:19.400 And I am Joe McCormick, and today we're going to 0:00:19.480 --> 0:00:23.600 do another baby looked at Me style topic. My daughter 0:00:23.680 --> 0:00:26.480 is ten months old now, and after I came back 0:00:26.480 --> 0:00:29.000 on the show, after I came back from parental leave, 0:00:29.040 --> 0:00:31.760 I think I warned you all that there would probably 0:00:31.840 --> 0:00:35.479 be plenty of baby looked at Me style content in 0:00:35.520 --> 0:00:37.880 the coming years. And this is one that has really 0:00:37.920 --> 0:00:41.919 harnessed my brain. It starts with an observation that I'm 0:00:41.960 --> 0:00:44.960 sure anybody out there who has or has ever had 0:00:45.040 --> 0:00:49.000 young children will recognize. And it is what one might 0:00:49.080 --> 0:00:55.040 call anomalous adhesion syndrome, the sudden realization that an unusual 0:00:55.160 --> 0:00:58.280 surface in your house has become sticky and you don't 0:00:58.280 --> 0:01:00.600 know how it happened. I don't know. This is one 0:01:00.600 --> 0:01:02.840 of the anomalous phenomena that we need to resort to 0:01:02.880 --> 0:01:07.520 the proof of aliens confirmed column for. But I don't know. 0:01:07.720 --> 0:01:10.280 We'll see. And in my case, it starts with my 0:01:10.440 --> 0:01:13.960 child eating like a frozen fruit smoothie pop. Rob, I 0:01:13.959 --> 0:01:16.399 don't know if you ever made these in your house. 0:01:16.440 --> 0:01:18.440 But it's a nice little treat, you know. You like 0:01:18.480 --> 0:01:21.480 blend up some strawberries and bananas and stuff and freeze 0:01:21.480 --> 0:01:22.880 it in the freezer with a little handle. 0:01:23.360 --> 0:01:27.400 Yeah. Yeah, we have done this plenty of times. I 0:01:27.400 --> 0:01:30.039 think we've stopped using them though, but they're still in 0:01:30.040 --> 0:01:32.839 the freezer. I don't know when we filled the mold last, 0:01:32.880 --> 0:01:34.240 but they're still awaiting use. 0:01:35.120 --> 0:01:37.160 Well, so you give one of these to a baby. 0:01:37.640 --> 0:01:40.240 You know she loves it, but no surprise that her 0:01:40.280 --> 0:01:43.760 face gets sticky. You would expect that her hands get sticky, 0:01:44.000 --> 0:01:47.400 the floor around her gets sticky. But then later maybe 0:01:47.400 --> 0:01:50.440 you're like pulling a book off the shelf and you 0:01:50.600 --> 0:01:55.080 notice that the underside of the bookshelf is sticky. How 0:01:55.120 --> 0:01:59.720 did that happen? We could insert the X files music 0:01:59.720 --> 0:02:03.120 sting here, but I do have a hypothesis. At first 0:02:03.120 --> 0:02:05.720 it was a little more perplexing, but I think maybe 0:02:05.760 --> 0:02:09.560 it's that the adults in the house are acting as 0:02:09.600 --> 0:02:13.880 an intermediary or as a vector of stickiness from one 0:02:14.320 --> 0:02:17.320 surface to the other. So like during frantic moments of 0:02:17.360 --> 0:02:21.359 dealing with the baby, an adult is maybe getting stickiness 0:02:21.400 --> 0:02:24.720 from the baby on themselves, and then touching you know, 0:02:24.760 --> 0:02:28.640 the bookshelf, for the refrigerator door handle or whatever it is. 0:02:29.680 --> 0:02:32.160 Hmmm, well, that's pretty good. I mean, on one hand, 0:02:32.160 --> 0:02:35.040 you could just say sticky baby touches everything, and then 0:02:35.200 --> 0:02:38.720 therefore everything is sticky. I still think that's a solid hypothesis, 0:02:40.280 --> 0:02:43.639 this transference of sticky. This also holds what holds up well. 0:02:43.680 --> 0:02:48.440 I think another possibility is heightened stickiness thanks to baby 0:02:48.560 --> 0:02:52.080 results in heightened awareness of stickiness, and therefore you're just 0:02:52.080 --> 0:02:55.799 more inclined to notice stickiness now that there is an 0:02:55.960 --> 0:02:58.200 enhanced stickiness culprit in the household. 0:02:58.960 --> 0:03:01.160 You know, normally, I would say that kind of explanation 0:03:01.240 --> 0:03:03.360 makes a lot of sense, but I think for me, 0:03:03.480 --> 0:03:07.400 psychologically it's the exact opposite. I used to have much 0:03:07.440 --> 0:03:10.360 more awareness of the ickiness of stickiness, but now having 0:03:10.360 --> 0:03:14.320 a baby, I am I think I am somewhat desensitized 0:03:14.480 --> 0:03:16.160 to the to the icky of the sticky. 0:03:16.800 --> 0:03:21.440 Hmmm. Interesting. Yeah, I mean we still seem like, I 0:03:21.520 --> 0:03:24.840 still feel like we have enhanced stickiness in the household 0:03:25.480 --> 0:03:27.520 even at this point. And I think part of it 0:03:27.639 --> 0:03:29.400 too is just like you get a third body in 0:03:29.440 --> 0:03:33.160 the house, or you know, in larger family households, you know, 0:03:33.240 --> 0:03:36.320 multiple more bodies, that's more folks coming in and out 0:03:36.360 --> 0:03:38.800 of the kitchen, that's more folks handling food. Yeah, there's 0:03:38.840 --> 0:03:42.680 just kind of this exponential swell of stickiness. And then 0:03:42.720 --> 0:03:44.920 how do you handle it? Do you just become desensitized 0:03:44.960 --> 0:03:46.560 to it? Or do you try and keep up the 0:03:46.640 --> 0:03:48.080 battle against the sticky? 0:03:49.040 --> 0:03:51.760 Keeping up the battle is really a slog because another 0:03:51.800 --> 0:03:54.400 part of you know, a baby learning to appreciate solid 0:03:54.400 --> 0:03:57.640 foods is a lot of throwing foods on the floor, 0:03:57.720 --> 0:03:59.600 a lot of the floor. 0:04:00.040 --> 0:04:03.440 How did people cope with carpets, wall to wall carpets 0:04:03.640 --> 0:04:05.560 and children in the past. I don't know. 0:04:05.960 --> 0:04:08.560 Oh, I don't want to think about it. But anyway, 0:04:08.640 --> 0:04:12.600 so this got my brain cranking on the subject of stickiness, 0:04:13.000 --> 0:04:16.039 and I wanted to kick off a series today exploring 0:04:16.080 --> 0:04:19.520 the concept of stickiness and it's many wonderful, terrible and 0:04:19.600 --> 0:04:24.239 mysterious forms. So one place I was kind of foiled 0:04:24.320 --> 0:04:27.680 right at the beginning is I was like, Okay, is 0:04:27.720 --> 0:04:30.000 there just an answer to the question, sort of a 0:04:30.080 --> 0:04:34.440 chemistry or material science question, what makes a sticky thing sticky? 0:04:35.160 --> 0:04:36.720 I think it turns out this is one of those 0:04:36.800 --> 0:04:39.719 questions that seems like it should have a very simple answer, 0:04:39.760 --> 0:04:43.640 but in fact is rather difficult and complex, because while 0:04:43.800 --> 0:04:48.039 stickiness seems like one phenomenon to us, you know, we 0:04:48.120 --> 0:04:50.840 have a single word for it, it's actually a lot 0:04:50.880 --> 0:04:54.599 of different things. And I've been reading a book that 0:04:54.680 --> 0:04:58.159 addresses this a bit. It's a book called Sticky, The 0:04:58.240 --> 0:05:02.320 Secret Science of Surfaces, by Laurie Winkless from Bloomsbury twenty 0:05:02.360 --> 0:05:05.520 twenty three. So this is a new popular science book. 0:05:05.920 --> 0:05:08.760 It's not just about stickiness. It's also about slipperiness and 0:05:08.839 --> 0:05:13.040 generally about surface interactions, and the science thereof is by 0:05:13.080 --> 0:05:16.800 this author named Luri Winkless. And for everybody who says 0:05:16.839 --> 0:05:19.800 that you know, book jacket blurbs don't matter, I will 0:05:19.800 --> 0:05:21.479 say this is a case where I was swayed. I 0:05:21.520 --> 0:05:23.880 was convinced to go ahead and buy this one because 0:05:23.920 --> 0:05:25.839 it had a positive blurb from Mary Roach. 0:05:26.680 --> 0:05:29.479 Oh yeah, friend of the show Mary Roach. Always a 0:05:29.560 --> 0:05:30.279 ringing endorsement. 0:05:30.520 --> 0:05:33.760 But anyway, in the introduction to her book, Winkless reveals 0:05:33.760 --> 0:05:36.760 something that kind of surprised me, which is that despite 0:05:36.800 --> 0:05:40.600 the fact that stickiness and slipperiness are essential and probably 0:05:40.800 --> 0:05:44.600 universally recognized properties of substances in the world around us. 0:05:44.800 --> 0:05:49.200 You know they have crucial and perfectly well understood everyday meanings. 0:05:49.839 --> 0:05:53.600 To quote from her introduction, the words sticky and slippery 0:05:53.680 --> 0:05:57.440 are also not true materials properties in the way that 0:05:57.520 --> 0:06:01.960 say hardness and thermal conductivity are. They have no agreed 0:06:02.040 --> 0:06:05.839 upon scientific definitions and no specific metrics that can be 0:06:05.920 --> 0:06:09.359 used to quantify or compare them. Now, of course, stickiness 0:06:09.360 --> 0:06:13.240 and slipperiness do involve a number of well understood and 0:06:13.279 --> 0:06:19.760 mathematically well defined physics concepts like friction, viscosity, elasticity, and 0:06:19.839 --> 0:06:23.600 so forth. Apparently, they in themselves are kind of more 0:06:23.680 --> 0:06:26.760 vague and complex concepts, and they describe a number of 0:06:26.760 --> 0:06:29.800 different phenomena with different causes. So when you say that 0:06:30.000 --> 0:06:33.440 glue is sticky, and velcrow is sticky, and sugar syrup 0:06:33.520 --> 0:06:37.440 is sticky, you're using one word to describe a similar 0:06:37.440 --> 0:06:41.159 property these substances have. But the explanations can go in 0:06:41.160 --> 0:06:45.880 a variety of different directions. So this exploration of stickiness 0:06:45.960 --> 0:06:48.040 over the next few episodes will not be a single 0:06:48.040 --> 0:06:51.760 straight highway, but a bunch of diverging roads. Though, I 0:06:51.839 --> 0:06:55.560 think because we started with the example of food based 0:06:55.600 --> 0:06:58.280 substances getting on things and making them sticky. I think 0:06:58.320 --> 0:07:01.280 it might be good to stick to food for a bit. 0:07:02.320 --> 0:07:05.560 Let's stick to the food for a bit, yes, Because, yeah, 0:07:05.600 --> 0:07:09.000 stickiness is not always a byproduct of misplaced or spilled 0:07:09.000 --> 0:07:13.080 food treats. Sometimes it's a vital part of the culinary experience. 0:07:14.120 --> 0:07:17.720 And as we'll get into this, might not be as 0:07:17.760 --> 0:07:21.160 obvious to all listeners out there when we talk about, oh, 0:07:21.200 --> 0:07:23.560 don't you love it when the food is sticky? Don't 0:07:23.600 --> 0:07:27.120 you love it when the food is chewy? There's actually 0:07:27.200 --> 0:07:32.320 some rather stark differences that can be observed across different 0:07:32.320 --> 0:07:33.080 food cultures. 0:07:33.440 --> 0:07:35.880 Now, I'm sure when a lot of people think sticky foods, 0:07:35.920 --> 0:07:38.800 you immediately think sugar syrups and candy. But we're going 0:07:38.840 --> 0:07:40.520 to go in a slightly different direction here. 0:07:41.280 --> 0:07:45.240 That's right, because you have most chewy and sticky candies. 0:07:45.280 --> 0:07:48.640 I mean, yeah, that's the sweet dimension. But the example 0:07:48.640 --> 0:07:51.520 we're going to bring up here, it can be enjoyed sweet, 0:07:51.520 --> 0:07:54.840 it can be enjoyed savory. I'm talking about the sticky 0:07:54.840 --> 0:07:59.960 food par excellence. Sticky rice. So you may have a 0:08:00.080 --> 0:08:02.440 counted sticky rice in different forms. I mean, there's like 0:08:02.800 --> 0:08:06.760 bamboo sticky rice, there's Oh, there's mango sticky rice, which 0:08:07.120 --> 0:08:11.200 I think is absolutely amazing. You know, it's going to 0:08:11.240 --> 0:08:13.200 be different depending on you know, exactly what sort of 0:08:13.240 --> 0:08:16.400 mango you you have on there, but you can and 0:08:16.640 --> 0:08:19.080 sticky rice can be enjoyed with savory foods, it can 0:08:19.120 --> 0:08:22.640 be enjoyed with sweet foods. It's just absolutely tremendous. 0:08:22.840 --> 0:08:24.880 Now, when you say the phrase sticky rice, you could 0:08:24.880 --> 0:08:27.400 just be talking about rice and using sticky as an 0:08:27.440 --> 0:08:30.840 adjective to describe the rice. Because rice is, as we'll discuss, 0:08:31.160 --> 0:08:34.720 different varieties of rice are a varying levels of stickiness. 0:08:35.000 --> 0:08:37.280 But there is also a type of rice that is 0:08:37.320 --> 0:08:38.880 specifically sticky rice. 0:08:39.320 --> 0:08:45.680 That's right. Specifically, it's a Ariza sativa variant glutenosa, also 0:08:45.760 --> 0:08:48.959 known as glutenous rice. But don't let the name deceia view. 0:08:49.280 --> 0:08:52.480 It doesn't actually contain gluten. It is merely glutenous in 0:08:52.559 --> 0:08:54.080 that it is glue like or. 0:08:53.960 --> 0:08:58.280 Sticky, also sometimes called sweet rice. The last time I 0:08:58.400 --> 0:09:01.280 bought it at one of our local Asian markets, it 0:09:01.360 --> 0:09:03.800 was just in a bag that had sweet rice written 0:09:03.800 --> 0:09:04.080 on it. 0:09:04.679 --> 0:09:09.000 Yeah, and there are numerous cultivars of this particular type 0:09:09.040 --> 0:09:12.360 of rise and it's grown throughout Southeast and East Asia. 0:09:12.960 --> 0:09:17.160 This and the among the cultivars, you have mochigami, which 0:09:17.200 --> 0:09:20.080 is key to Japanese mochi, which is also one of 0:09:20.120 --> 0:09:23.600 life's great pleasures. Now where it gets interesting because ultimately 0:09:23.760 --> 0:09:26.160 the question arises where does the stickiness come in? What 0:09:26.280 --> 0:09:32.560 makes it stickier? So typical rice contains two starches, amelos 0:09:32.960 --> 0:09:37.640 and amelo pectin, but sticky rice lacks amelos and its 0:09:37.679 --> 0:09:41.600 absence leads to this sticky quality that we have. This 0:09:41.679 --> 0:09:45.160 is due to a mutation in its waxy gene. DNA 0:09:45.240 --> 0:09:48.840 evidence suggests that it emerged a single time somewhere in 0:09:48.960 --> 0:09:56.400 Southeast Asia, and the resulting stickiness was seemingly light, preserved, encouraged. 0:09:56.640 --> 0:09:58.520 You know that we see this story time and time 0:09:58.559 --> 0:10:03.360 again throughout the history of domesticated and cultivated foods, where 0:10:03.679 --> 0:10:07.360 something changes in the particular plant and we realize, oh, 0:10:07.480 --> 0:10:09.040 this is even better than before. 0:10:10.000 --> 0:10:12.319 Yeah, I can see that. In another way, I kind 0:10:12.360 --> 0:10:16.720 of think about a glutinous rice as blasting off of 0:10:16.800 --> 0:10:21.440 one end of the rice experience spectrum. So, just from 0:10:21.440 --> 0:10:25.280 personal experience in the kitchen, I'm familiar with the properties 0:10:25.280 --> 0:10:27.520 of different kinds of cooked rice, and there is a 0:10:27.600 --> 0:10:32.640 general pattern that longer grain rice varieties tend to be 0:10:32.840 --> 0:10:36.360 firmer and less sticky, so they stick to each other less. 0:10:36.400 --> 0:10:39.600 So you think of the example of basmadi rice used 0:10:39.640 --> 0:10:42.080 in a lot of Indian cuisine and other long grain 0:10:42.200 --> 0:10:46.240 rice is they tend to have grains that separate from 0:10:46.240 --> 0:10:49.720 one another more easily and remain firmer after cooking. So 0:10:50.320 --> 0:10:52.960 these rices kind of flake when you toss them with 0:10:53.000 --> 0:10:55.920 a fork after cooking. Rob you know that experience. 0:10:55.679 --> 0:10:57.800 Yeah, yeah, And of course this becomes vital too if 0:10:57.800 --> 0:11:00.840 you're going to be potentially eating with chopsticks. You know 0:11:00.920 --> 0:11:02.640 what kind of rises are going to clump together in 0:11:02.640 --> 0:11:03.440 which ones are going. 0:11:03.360 --> 0:11:06.679 To fall apart. Yes, these would be more difficult to 0:11:06.720 --> 0:11:09.200 eat with chopsticks, though you know, with enough practice you 0:11:09.240 --> 0:11:12.679 need almost anything with chopsticks. Yeah, yeah, especially if you 0:11:12.760 --> 0:11:15.439 got some kind of saucy, wet thing to kind of 0:11:15.480 --> 0:11:19.240 stick it together. But yes, the grains that separate from 0:11:19.240 --> 0:11:21.960 one another more easily like this, the long grain rices 0:11:22.040 --> 0:11:26.200 are more difficult. Meanwhile, shorter grain rices tend to be 0:11:26.280 --> 0:11:29.360 softer in texture and stickier. They stick to each other 0:11:29.400 --> 0:11:31.760 and stick to other things more easily. So you can 0:11:31.760 --> 0:11:34.520 think of short grain rices like you know ar boreo 0:11:34.679 --> 0:11:38.480 rice which is commonly used in risotto, or short grain 0:11:38.559 --> 0:11:42.079 sushi rice which is tender and sticks together nicely to 0:11:42.840 --> 0:11:45.680 you know, make into sushi rolls or other multiple forms. 0:11:46.280 --> 0:11:49.480 And this correlates to what you mentioned, Rob that changing 0:11:49.600 --> 0:11:54.320 ratio of ammelos to amelopectin, longer grain rices tend to 0:11:54.360 --> 0:11:57.600 have more ammelos and shorter grain rices tend to have less. 0:11:58.040 --> 0:12:01.679 Glutenous rice goes even beyond the normal short grain rice. 0:12:01.920 --> 0:12:05.920 It has especially low ammelose content and high a melopectin, 0:12:06.400 --> 0:12:09.560 which causes the rice to, once it's cooked, clump together 0:12:09.640 --> 0:12:13.440 for molding purposes in cooking, and retain a really sticky 0:12:13.480 --> 0:12:17.280 adhesion between grains while eating. It's also worth noting that 0:12:17.320 --> 0:12:21.199 sticky rice is used to create a number of secondary 0:12:21.280 --> 0:12:24.439 food products like Shoushing wine, which is used in a 0:12:24.440 --> 0:12:28.240 lot of Chinese cooking, is usually made by fermenting a 0:12:28.880 --> 0:12:33.880 mash containing glutinous rice. In particular, Japanese sake is an 0:12:34.400 --> 0:12:36.960 alcoholic beverage that I think is also often made with 0:12:37.520 --> 0:12:41.200 fermented sticky rice. But I was getting curious about what 0:12:41.480 --> 0:12:45.600 actually makes the difference. Why do these different ratios of 0:12:45.679 --> 0:12:50.199 amelos and amlopectin change the stickiness and the texture of rice. 0:12:50.240 --> 0:12:52.959 Like what's happening at the sort of at the molecular level. 0:12:53.400 --> 0:12:55.360 So I was looking all over for a good explanation 0:12:55.440 --> 0:12:58.480 that I could actually understand of what exactly is happening here, 0:12:58.520 --> 0:13:01.400 and eventually I found a great article about this by 0:13:01.440 --> 0:13:04.720 an author named Guy Crosby, who writes about food science 0:13:04.760 --> 0:13:07.520 for America's Test Kitchen and teaches at the Department of 0:13:07.600 --> 0:13:11.360 Nutrition at Harvard's chan School of Public Health. And so 0:13:11.679 --> 0:13:14.760 here's the way Crosby explained it. You got to start 0:13:14.760 --> 0:13:19.240 off by understanding what starch is. Starch is a carbohydrate 0:13:19.280 --> 0:13:22.960 that is found in lots of foods, and it is 0:13:23.040 --> 0:13:28.800 the natural way that plants store energy, store food energy 0:13:28.840 --> 0:13:31.840 that they make via the process of photosynthesis. And so 0:13:32.280 --> 0:13:34.839 this is kind of an interesting connection to like, when 0:13:34.880 --> 0:13:37.200 you're thinking about the food you eat, think all the 0:13:37.200 --> 0:13:40.200 way back to like how that energy entered the planet 0:13:40.280 --> 0:13:44.400 Earth in the form of sunlight and turned into the 0:13:44.440 --> 0:13:46.840 food on your plate. So, of course plants make their 0:13:46.880 --> 0:13:49.600 own food by way of photosynthesis, which means they are 0:13:49.760 --> 0:13:54.040 forcing a chemical reaction between carbon dioxide in the air 0:13:54.280 --> 0:13:58.240 and water, and that chemical reaction is powered by the 0:13:58.360 --> 0:14:02.160 energy from sunlight, and it produces is glucose or sugar 0:14:02.240 --> 0:14:05.160 carbohydrates as a product that's the food for the plant, 0:14:05.520 --> 0:14:09.920 and then oxygen as a byproduct. Plants then convert the 0:14:10.120 --> 0:14:14.760 sugar they produce through photosynthesis into starch, which is a polymer. 0:14:14.800 --> 0:14:20.160 It's this huge macromolecule that is composed of smaller individual 0:14:20.200 --> 0:14:24.920 molecules all linked together in a big chain. And starch 0:14:25.040 --> 0:14:29.200 is a natural form of high density energy storage. It's 0:14:29.200 --> 0:14:32.320 a way to squeeze a ton of chemical energy into 0:14:32.360 --> 0:14:36.000 a very compact space. All of this sugar is packed 0:14:36.040 --> 0:14:41.000 into one tight, gigantic molecular structure. This starch structure is 0:14:41.040 --> 0:14:44.000 known as a granule. So sometimes you can actually look 0:14:44.080 --> 0:14:48.200 up like microscopic imagery of starch granules and they have 0:14:48.280 --> 0:14:51.520 a interesting little little like if you look at a 0:14:51.520 --> 0:14:53.960 cross section of one. Sometimes they'll have these little rings, 0:14:54.040 --> 0:14:56.200 kind of like the rings of a tree. That's interesting. 0:14:57.760 --> 0:15:02.040 And when plants make these starch granules, they are storing 0:15:02.040 --> 0:15:06.160 the glucose in starch in two distinct molecular forms. One 0:15:06.280 --> 0:15:09.840 is amylose and one is Amylopectin. These two starches we 0:15:09.880 --> 0:15:13.840 mentioned earlier ammelos is a linear molecule which is smaller 0:15:13.880 --> 0:15:17.480 in size, and amylopectin is a larger molecule with a 0:15:17.560 --> 0:15:21.960 kind of branching out structure, And these amelos and amylopectin 0:15:22.240 --> 0:15:26.320 pectin molecules are organized into these tight structures called granules. 0:15:26.360 --> 0:15:29.600 And then inside the granules there are layers with a 0:15:29.600 --> 0:15:33.440 different makeup. So there are these like tightly crystallized, highly 0:15:33.440 --> 0:15:37.800 structured organized layers, and then there are more amorphous, non 0:15:37.880 --> 0:15:43.400 crystallized layers with more random arrangements of amylose molecules and 0:15:43.480 --> 0:15:48.040 amylopectin any kind of non regular pattern. So why does 0:15:48.080 --> 0:15:50.280 that matter, Well, you got to look at what happens 0:15:50.320 --> 0:15:54.040 when starch granules get cooked in hot water. When the 0:15:54.080 --> 0:15:58.120 starch granules are in water above a certain temperature, that 0:15:58.640 --> 0:16:02.360 water starts to pin trait the starch granule, causing it 0:16:02.440 --> 0:16:06.240 to swell. So you can imagine water molecules like soaking 0:16:06.400 --> 0:16:08.960 into something I don't know, like a couch cushion or 0:16:09.000 --> 0:16:12.400 something and making it like swell up, and that makes 0:16:12.400 --> 0:16:14.400 it swell up kind of like a balloon in a way. 0:16:14.680 --> 0:16:17.720 And as these starch granules in hot water get hotter 0:16:17.800 --> 0:16:22.000 and hotter, they eventually reach a breaking point their maximum 0:16:22.080 --> 0:16:26.080 volume and viscosity, as Crosby says, and this is called 0:16:26.080 --> 0:16:30.040 their gelatinization temperature. And eventually what happens is they burst. 0:16:30.280 --> 0:16:33.840 They just like leak pieces of starch molecules all out 0:16:33.880 --> 0:16:38.040 into the water around them. Exactly what temperature this is 0:16:38.160 --> 0:16:41.400 depends on the type of starch e g. What plant 0:16:41.440 --> 0:16:44.600 it comes from. And a key factor is the ratio 0:16:44.640 --> 0:16:48.440 of amylose to amelopectin in each starch granule. So the 0:16:48.480 --> 0:16:51.400 more amylose there is in the starch, the more the 0:16:51.440 --> 0:16:53.720 swelling of the granule in the presence of hot water 0:16:53.840 --> 0:16:56.400 is delayed. So you can kind of think of amylose 0:16:56.720 --> 0:17:01.400 as an armor against gelatinization. The more amlos, the higher 0:17:01.480 --> 0:17:05.480 the gelatinization temperature, and the more the granule fights off 0:17:05.600 --> 0:17:09.600 the gelatinization process. And then Crosby uses the example of 0:17:09.960 --> 0:17:13.720 rice to show this process. He writes, quote, long grain 0:17:13.800 --> 0:17:16.840 rice contains about twenty two to twenty eight percent ammelos 0:17:16.880 --> 0:17:20.600 by weight, Medium grains contain about sixteen to eighteen percent 0:17:20.640 --> 0:17:24.040 by weight, while short grain contains less than fifteen percent 0:17:24.320 --> 0:17:27.760 to almost no ammelos. Varieties of long grain rice have 0:17:27.800 --> 0:17:30.760 a gelatinization temperature above one hundred and fifty eight degrees 0:17:30.800 --> 0:17:34.680 fahrenheit or seventy degrees celsius, while waxy short grain rice 0:17:34.760 --> 0:17:37.960 gelatinizes at about one hundred and forty four degrees fahrenheit 0:17:38.280 --> 0:17:41.639 or sixty two degrees celsius. So the temperature in the 0:17:41.680 --> 0:17:45.040 short grain rice is the temperature for gelatinization is lower, 0:17:45.280 --> 0:17:49.080 meaning it happens more easily. So the granules of starch 0:17:49.119 --> 0:17:52.840 in short grain rice with lower ammelose content reach their 0:17:53.000 --> 0:17:56.920 gelatinization point and burst at a lower temperature. And when 0:17:56.960 --> 0:18:00.760 the starch granules burst, they flood the surrounding one with 0:18:00.960 --> 0:18:05.879 disorganized small chunks of amylos and amylopectant of just little 0:18:05.920 --> 0:18:10.400 bits of starch, Crosby writes quote, creating an infinite network 0:18:10.440 --> 0:18:13.840 of entwined molecules that trap water and thicken to a 0:18:13.920 --> 0:18:19.600 gel on cooling. So this mesh of loose, uncrystallized starch 0:18:19.680 --> 0:18:23.639 molecules thickens the water and causes the rice grains to 0:18:23.720 --> 0:18:27.480 stick together. And you can actually observe a similar principle 0:18:27.800 --> 0:18:31.520 when you use starch to thicken other foods thicken like 0:18:31.560 --> 0:18:33.719 a soup or a sauce. If you've ever used a 0:18:34.320 --> 0:18:37.960 roue based on wheat flour or a corn starch slurry. 0:18:38.000 --> 0:18:41.560 It's the same principle. Corn starch flour, potato starch and 0:18:41.600 --> 0:18:46.040 so forth all undergo the same gelatinization process, though at 0:18:46.080 --> 0:18:49.760 different temperatures and rates. So the starch granules will swell 0:18:49.840 --> 0:18:53.000 up and eventually burst in hot water, and this has 0:18:53.040 --> 0:18:57.600 the effect of increasing the viscosity, meaning the thickness and 0:18:57.840 --> 0:19:01.800 the stickiness of the water based or sauce. So that 0:19:01.920 --> 0:19:05.280 is how the lower ratio of ammelos to amelopectin makes 0:19:05.320 --> 0:19:06.480 the cooked rice sticky. 0:19:07.040 --> 0:19:10.960 Ah, fascinating, fascinating. So all that's going on at the 0:19:11.400 --> 0:19:14.840 at the micro level and at the macro level, you're 0:19:14.880 --> 0:19:18.399 just enjoying some some sticky rice. Maybe a little sweet, 0:19:18.400 --> 0:19:21.040 maybe you're a little savory. It kind of depends on 0:19:21.119 --> 0:19:25.240 the particular dish. I don't think we can properly prepare 0:19:25.280 --> 0:19:29.119 you for the stickiness just in this audio podcast is 0:19:29.119 --> 0:19:32.000 something you need to fully to fully appreciate. You need 0:19:32.040 --> 0:19:36.600 to try it for yourself. But it's it's generally like 0:19:36.640 --> 0:19:39.360 when I've had it, oftentimes, not only could you eat 0:19:39.400 --> 0:19:41.480 it with a with a pair of chopsticks, you could 0:19:41.520 --> 0:19:44.199 eat it with like one of those little like wooden 0:19:44.240 --> 0:19:46.320 planks that comes They used to come on the top 0:19:46.359 --> 0:19:48.520 of ice creams. You could eat it with a popsicle stick, 0:19:48.560 --> 0:19:48.840 you know. 0:19:49.080 --> 0:19:52.480 Mm hmm. Sticky rice is often used for a like 0:19:52.720 --> 0:19:55.399 molding purposes, so you can wrap it round foods, or 0:19:55.440 --> 0:19:57.520 you can just use it as sort of like forming 0:19:57.600 --> 0:20:01.000 little little bits of it or paddles of it in 0:20:01.040 --> 0:20:13.000 your hand and scoop up foods with it. But there's 0:20:13.040 --> 0:20:17.760 another thing about the texture of sticky rice, which is 0:20:17.840 --> 0:20:21.840 that I think it's because of this gelatinization that it 0:20:21.920 --> 0:20:24.640 has a similar thing going on that like risotto has, 0:20:24.680 --> 0:20:26.320 which is a creaminess. 0:20:27.720 --> 0:20:30.720 Yeah, yeah, I can definitely take on this creamy, gooey 0:20:31.920 --> 0:20:36.360 kind of texture, has this incredible mouth feel. It can 0:20:36.400 --> 0:20:39.280 make for an overpoweringly good dessert, but again also works 0:20:39.320 --> 0:20:43.280 very well in savory and plays a very important role 0:20:43.359 --> 0:20:50.320 in various cuisines in various traditions, especially I've read in 0:20:50.480 --> 0:20:55.280 the culinary traditions of Laos in Laotian cooking. As pointed 0:20:55.320 --> 0:20:58.080 out by Mike Ives in a Taste of Sticky Rice, 0:20:58.400 --> 0:21:01.960 Laos's national dish, it can be steamed twice during the 0:21:02.000 --> 0:21:04.879 course of the day, beginning first thing in the morning. 0:21:04.960 --> 0:21:08.040 So like traditionally sticky rice is something you make right away, 0:21:08.080 --> 0:21:10.080 like this is how you start off your day. A 0:21:10.160 --> 0:21:14.040 third steaming ives rights is said to just make it 0:21:14.080 --> 0:21:17.280 too chewy to eat at that point, but the author 0:21:17.320 --> 0:21:19.440 points out that quote a hunk of sticky rice is 0:21:19.480 --> 0:21:24.320 a delicious bread like dipping implement. So I looked around 0:21:24.320 --> 0:21:26.560 at some other sources on this, and yet traditionally in 0:21:26.640 --> 0:21:30.000 Laotian cuisine, one rolls it up with one's fingers and 0:21:30.040 --> 0:21:33.280 then dips it into sauces, which is, you know, it 0:21:33.400 --> 0:21:35.639 is even a little bit different than other uses of 0:21:35.640 --> 0:21:37.440 sticky rice. You might be more familiar with. 0:21:37.760 --> 0:21:40.440 One of the many great world food traditions of make 0:21:40.480 --> 0:21:42.720 your own utensils and then eat the utensil. 0:21:43.359 --> 0:21:46.880 Yeah, yeah, I've been to I think I think I've 0:21:46.880 --> 0:21:50.560 only been to one Laotian restaurant a couple of times, 0:21:50.600 --> 0:21:53.960 and I don't remember enjoying the sticky rice like this, 0:21:54.320 --> 0:21:56.240 And now I want to. I really want to seek 0:21:56.240 --> 0:21:59.399 it out and have this experience. Anyway, the importance of 0:21:59.440 --> 0:22:02.560 sticky rice and laos goes well beyond just you know, 0:22:02.680 --> 0:22:05.600 how you start your day. It factors into Laotian Buddhist 0:22:05.680 --> 0:22:08.000 rights and traditions will come back a little to a 0:22:08.040 --> 0:22:10.800 little bit to this in just a few minutes here. 0:22:11.359 --> 0:22:14.000 But it also was apparently long sought after by monks 0:22:14.119 --> 0:22:18.399 because quote as ice rites quote, it takes longer to 0:22:18.480 --> 0:22:23.200 digest than white rice does. It states hunger for longer periods. 0:22:24.000 --> 0:22:26.680 So I thought that that was an interesting tidbit. Is 0:22:26.840 --> 0:22:29.680 another reason to have it first thing in the morning. Now, 0:22:30.240 --> 0:22:32.920 whether that actually how much of that is the actual 0:22:33.200 --> 0:22:36.000 science of the digestion of sticky rice versus other varieties 0:22:36.040 --> 0:22:39.240 of rice, I don't know, but and I can't help 0:22:39.280 --> 0:22:41.960 but wonder too if there's some version of like food 0:22:42.080 --> 0:22:44.520 sticking to your ribs, if there's some sort of like 0:22:44.800 --> 0:22:49.720 idea of that in Laotian traditions as well. I'm not 0:22:49.760 --> 0:22:54.359 sure linguistic stickiness and so forth. Anyway, getting into the 0:22:54.400 --> 0:22:56.640 just sort of the history of rice and the possible 0:22:56.760 --> 0:23:00.280 like history of like when did sticky rice emerge? There 0:23:00.320 --> 0:23:02.399 are various dates you'll come across for some of this. 0:23:02.400 --> 0:23:04.080 There's so a lot of work has gone into like, well, 0:23:04.400 --> 0:23:07.240 you know, when do we see this particular rice variety 0:23:07.280 --> 0:23:11.119 pop up? And what does genetic information tell us the 0:23:11.160 --> 0:23:15.399 domesticated species or Za sativa or Asian rice evolved starting 0:23:15.440 --> 0:23:18.720 approximately nine thousand years ago. I've read this according to 0:23:18.960 --> 0:23:24.880 Filipino American biologist Michael Pruganin in twenty ten. I've also 0:23:24.920 --> 0:23:28.080