WEBVTT - TechStuff Classic: How Tech Could Make Better Chocolate 0:00:04.440 --> 0:00:12.440 Welcome to tech Stuff, a production from iHeartRadio. Hey there, 0:00:12.480 --> 0:00:16.800 and welcome to tech Stuff. I'm your host, Jonathan Strickland. 0:00:16.800 --> 0:00:20.240 I'm an executive producer with iHeartRadio. And how the tech 0:00:20.280 --> 0:00:24.160 are you? It is time for a classic episode of 0:00:24.280 --> 0:00:28.840 tech Stuff. This episode originally published way back on July sixth, 0:00:29.280 --> 0:00:32.680 twenty sixteen. Really, I probably should have published this one 0:00:33.240 --> 0:00:36.240 on Valentine's Day now that I look at the topic. 0:00:36.320 --> 0:00:42.000 The topic is how tech could make better chocolate. Let's listen. 0:00:42.040 --> 0:00:48.599 In so, a consulting firm working on behalf of Mars Incorporated, 0:00:48.800 --> 0:00:52.320 which is a giant candy company that makes a lot 0:00:52.320 --> 0:00:56.120 of different chocolate products. This consulting firm went to a 0:00:56.120 --> 0:00:59.720 group of physicists at Temple University, and physicist is one 0:00:59.720 --> 0:01:04.120 of those words I have difficulty pronouncing. I think I 0:01:04.240 --> 0:01:07.360 might just say scientists. Scientists at Temple University. Hey, that's 0:01:07.400 --> 0:01:10.240 way better. And these guys had developed a method to 0:01:10.319 --> 0:01:16.080 make crude oil flow more easily through pipes using electric fields. 0:01:16.560 --> 0:01:19.480 So the question that the consulting firm had was could 0:01:19.520 --> 0:01:21.480 you do the same thing you did for crude oil 0:01:21.560 --> 0:01:25.520 for chocolate? And here's a spoiler alert, yeah they could, 0:01:26.160 --> 0:01:28.640 but I want to talk more about what they did 0:01:28.720 --> 0:01:32.840 and how they did it because it's a really interesting story. 0:01:33.680 --> 0:01:36.440 So I'm going to go into a bit more detail 0:01:36.800 --> 0:01:41.040 about the physics and the technology behind the scientist solution 0:01:41.240 --> 0:01:43.640 for this problem. It's pretty cool, and a lot of 0:01:43.680 --> 0:01:46.360 it was stuff I had no idea about before I 0:01:46.400 --> 0:01:48.720 began to research the story. So today's episode is going 0:01:48.800 --> 0:01:53.320 to be about chocolate. It's going to be about viscous fluids, 0:01:53.360 --> 0:01:58.640 about electroreological fluids and how an electric field can change 0:01:58.680 --> 0:02:03.560 their fluidic properties, specifically viscosity. So yeah, this episode's going 0:02:03.600 --> 0:02:06.520 to be science heavy, but there's also chocolate, so stick around. 0:02:06.560 --> 0:02:09.720 You know, everyone loves chocolate. So let's get into the 0:02:09.760 --> 0:02:15.520 physics first. Now, fluid dynamics is pretty complicated, and also 0:02:15.919 --> 0:02:18.880 there's some stuff that's related to this that falls into 0:02:18.919 --> 0:02:23.760 the category of misinformation about viscosity. So I'll be talking 0:02:23.800 --> 0:02:27.040 a lot about not just the principles in general, but 0:02:27.120 --> 0:02:33.000 some specific myths that I would like to bust as 0:02:33.440 --> 0:02:35.519 some of my former coworkers used to do on a 0:02:35.560 --> 0:02:39.120 regular basis. So, first of all, viscosity is a property 0:02:39.120 --> 0:02:42.840 of fluids or semi fluids, and it can be described 0:02:42.919 --> 0:02:46.920 as a fluid's thickness or stickiness, and its resistance to 0:02:47.360 --> 0:02:52.040 flowing due to internal friction. More accurately, viscosity is a 0:02:52.080 --> 0:02:55.200 measure of the resistance of a fluid's deformation due to 0:02:55.360 --> 0:03:00.519 tensile or shear stress. Now, sheer stress is mechanical stress 0:03:00.560 --> 0:03:06.200 that's parallel to the surface of that substance. So you 0:03:06.240 --> 0:03:10.960 could think of sheer stress as it's not perpendicular. It's 0:03:11.000 --> 0:03:13.640 not like an impact, right, It's more of a tearing 0:03:14.560 --> 0:03:17.920 tenstyle stress is a pulling stress rather than a compression stress, 0:03:17.960 --> 0:03:22.120 So again, instead of compressing stuff closer together, it's about 0:03:22.120 --> 0:03:26.279 pulling stuff further apart. And water has a pretty low viscosity. 0:03:27.120 --> 0:03:31.720 Honey has a very high viscosity. So we actually measure 0:03:31.800 --> 0:03:38.240 viscosity in units called poises poises. Water at room temperature 0:03:38.280 --> 0:03:41.920 twenty degrees celsius or so has a viscosity of zero 0:03:42.120 --> 0:03:46.720 point zero one poises or acenti poise. In other words, 0:03:47.400 --> 0:03:50.520 a thick oil might have a viscosity of one point 0:03:50.680 --> 0:03:55.920 zero poise. Now we measure viscosity with a viscometer. I'm 0:03:55.960 --> 0:03:58.720 not making that up. It's actually the name of the 0:03:58.720 --> 0:04:03.960 tool used to measure fluid's viscosity. Now, typically we will 0:04:04.000 --> 0:04:08.480 call a liquid viscous if its viscosity is higher than 0:04:08.520 --> 0:04:11.920 that of waters, and if the viscosity is lower than 0:04:11.960 --> 0:04:14.880 that of waters, because water is not the least viscous 0:04:14.920 --> 0:04:18.560 material that we know of, if it has a lower viscosity, 0:04:18.600 --> 0:04:22.640 then water we call that fluid mobile. So some fluids 0:04:22.680 --> 0:04:25.320 are so viscous that they can actually seem to be 0:04:25.400 --> 0:04:29.600 a solid, And this leads us to that misinformation I 0:04:29.640 --> 0:04:32.440 was talking about. It's one of those things that I 0:04:32.520 --> 0:04:36.839 hear bandied about pretty well, not as frequently as it 0:04:36.960 --> 0:04:40.520 used to, but it's one of those mis understandings that 0:04:40.600 --> 0:04:42.839 gets passed around as fact every now and again. And 0:04:42.880 --> 0:04:47.000 that is the idea that glass is one of these fluids, 0:04:47.000 --> 0:04:50.880 that glass is actually a fluid that is so viscous 0:04:51.000 --> 0:04:53.080 that it appears to be a solid, And that is 0:04:53.279 --> 0:04:58.880 not true. Glass is not a very, very viscous fluid. 0:04:59.400 --> 0:05:03.719 It's a little more complicated than that. So here's the 0:05:03.720 --> 0:05:06.440 basic idea. People have noticed that if they look at 0:05:06.920 --> 0:05:12.080 windows and very old buildings like medieval churches, they see 0:05:12.120 --> 0:05:16.720 that the base of the window is thicker than the 0:05:16.760 --> 0:05:20.280 top of the window. And this has led some people 0:05:20.320 --> 0:05:25.280 to conclude to jump to a conclusion that the reason 0:05:25.320 --> 0:05:28.520 why the base is thicker than the top is that glass, 0:05:28.640 --> 0:05:33.520 over the course of centuries has been flowing downward, and 0:05:33.560 --> 0:05:38.480 that it's so slow that it's not detectable under normal situations. 0:05:38.800 --> 0:05:41.360 It's only over the course of centuries that you can 0:05:41.440 --> 0:05:44.880 see the difference. Here's the problem is that that's just 0:05:45.120 --> 0:05:48.640 not that's not the case. That's not true, it's not 0:05:48.680 --> 0:05:55.200 what's happening. If you look at the glass making approach 0:05:55.320 --> 0:05:59.239 in the Middle Ages, you'll see why there's a thicker 0:05:59.279 --> 0:06:03.039 part of the paine of glass. Glass was created generally 0:06:03.080 --> 0:06:06.440 speaking in the Middle Ages through something called the crown 0:06:06.800 --> 0:06:11.000 glass process. It's a pretty neat idea pretty neat way 0:06:11.000 --> 0:06:15.520 of making glass windows. Here's how it worked in general. First, 0:06:15.520 --> 0:06:19.159 you get your raw materials to make glass, and in 0:06:19.160 --> 0:06:22.440 the Middle Ages that was essentially sand and potash, and 0:06:22.480 --> 0:06:25.080 you mix it together and you melt them in a 0:06:25.200 --> 0:06:29.520 very hot furnace. Then you would get a glass blower 0:06:29.560 --> 0:06:32.480 with a pipe and they would get a roll out 0:06:32.520 --> 0:06:35.840 a lump of molten glass put on the pipe, blow 0:06:36.000 --> 0:06:39.160 out the glass, so they expand the glass outward before 0:06:39.279 --> 0:06:43.039 flattening it. So they don't just you know, create a 0:06:43.120 --> 0:06:45.800 globe of glass, They actually flatten it back out. Then, 0:06:45.920 --> 0:06:49.120 with the flat glass, which is still hot and still malleable, 0:06:49.160 --> 0:06:52.880 it hasn't cooled to the point where it is really solidified, 0:06:53.279 --> 0:06:56.159 you would put that on a disc, a spinning disc, 0:06:56.240 --> 0:06:58.880 and the disk spins around to draw out the glass 0:06:58.920 --> 0:07:02.200 to flatten it further. Sort of like how a pizza 0:07:02.240 --> 0:07:05.520 maker will toss and spin dough in the air in 0:07:05.600 --> 0:07:07.800 order to make that circular pizza. It's kind of similar 0:07:07.839 --> 0:07:12.200 to that. So the disk spins and the centripetal force, 0:07:12.920 --> 0:07:16.360 if you like, is pushing the glass outward toward the edges. 0:07:17.520 --> 0:07:21.200 So then once that's done, you would cut the glass 0:07:21.280 --> 0:07:25.560 into panes so that you could fit them in a window. Now, 0:07:25.840 --> 0:07:28.160 that would mean that when you would get anywhere close 0:07:28.160 --> 0:07:31.920 to where the edge of the glass was, the outer edge, 0:07:31.960 --> 0:07:33.600 because you put the glass on that disk and you 0:07:33.640 --> 0:07:37.280 spun it around, the outer edge was thicker than the 0:07:37.320 --> 0:07:40.600 rest of the glass, just because that's where the excess 0:07:40.680 --> 0:07:45.160 was accumulating as it was being pushed outward due to 0:07:45.200 --> 0:07:50.320 the spinning motion. So typically window makers would cut panes 0:07:50.400 --> 0:07:53.080 so that a thicker edge would only be on one 0:07:53.200 --> 0:07:55.480 side and they'd put that side at the bottom at 0:07:55.480 --> 0:07:58.920 the base of the window, so glass didn't flow to 0:07:59.000 --> 0:08:02.760 the base. Hundreds of years it started out like that. 0:08:02.840 --> 0:08:06.000 It was like that from the beginning. That being said, 0:08:06.040 --> 0:08:09.240 glass is a really interesting substance. It's what we would 0:08:09.320 --> 0:08:14.000 call an amorphous solid, so saying that it's a fluid 0:08:14.160 --> 0:08:17.360 or a liquid is not accurate. But it is an 0:08:17.360 --> 0:08:21.480 amorphous solid, which is a little hinky compared to other 0:08:21.520 --> 0:08:26.440 materials that you might be familiar with. So typically not everything, 0:08:26.560 --> 0:08:29.720 obviously metals and glass being exceptions, but a lot of 0:08:29.760 --> 0:08:33.560 solids have an ordered crystalline structure, so that means the 0:08:33.640 --> 0:08:38.080 molecules are organized in a pretty regular lattice. They form 0:08:38.760 --> 0:08:44.520 a nice repeating pattern that goes throughout the entire material. 0:08:45.640 --> 0:08:49.320 When you heat up this solid, those molecules start to 0:08:49.320 --> 0:08:52.200 shimmy and shake, some of the molecular bonds might start 0:08:52.240 --> 0:08:55.959 to break down a little bit, the bonds between one 0:08:56.080 --> 0:08:59.920 molecule and another. The essentially the crystalline order breaks down, 0:09:00.640 --> 0:09:02.640 and if you heat a solid beyond its melting point, 0:09:02.640 --> 0:09:05.840 the crystalline structure completely breaks down and molecules will begin 0:09:05.880 --> 0:09:09.480 to flow freely, or as freely as the viscosity of 0:09:09.520 --> 0:09:14.439 that fluid allows and there's a very clear delineation between 0:09:14.480 --> 0:09:18.200 the solid and liquid stages. You can see the difference 0:09:18.280 --> 0:09:22.920 molecularly from the way this substance looks when it's in 0:09:22.960 --> 0:09:26.880 solid form versus in liquid form, and we call that delineation, 0:09:27.240 --> 0:09:30.719 that border between the two the first order phase transition. 0:09:32.080 --> 0:09:37.000 It's obvious when you look at it from a microscopic standpoint. 0:09:37.040 --> 0:09:39.880 I mean it's obvious from a macroscopic standpoint two, because 0:09:40.440 --> 0:09:44.440 a solid behaves one way and a liquid behaves another way. Now, 0:09:44.440 --> 0:09:49.440 when you cool a liquid down, its viscosity tends to increase. 0:09:50.240 --> 0:09:54.120 If you introduce a nucleation site into the liquid, crystals 0:09:54.160 --> 0:09:57.319 can form and you get that nice solid structure again 0:09:57.920 --> 0:10:00.680 once you get down below what the melting point was. 0:10:02.120 --> 0:10:07.280 But glass doesn't do this. Glass doesn't form a crystalline structure. 0:10:08.200 --> 0:10:12.520 Glass's viscosity increases, so it does what other fluids do 0:10:12.559 --> 0:10:17.000 at that point. But since it doesn't crystallize, it solidifies 0:10:17.000 --> 0:10:20.679 in a different way. The molecules actually form an irregular arrangement, 0:10:21.360 --> 0:10:24.880 not that nice ordered structure that you see in other solids. 0:10:25.120 --> 0:10:29.800 But that irregular arrangement is still cohesive enough to maintain rigidity. 0:10:30.520 --> 0:10:34.160 So glass does become a solid, it's just not a 0:10:34.200 --> 0:10:39.480 crystalline solid. It's an amorphous solid. We'll be back with 0:10:39.520 --> 0:10:52.800 more about how technology could make better chocolate after these messages. Now, 0:10:52.920 --> 0:10:55.880 there's no first order phase transition here. It's not like 0:10:56.000 --> 0:10:58.599 if you looked at the liquid form of glass and 0:10:58.640 --> 0:11:01.679 the solid form of glass, you would a massive difference 0:11:01.840 --> 0:11:07.160 in the molecular structure. But there is a second order transition. 0:11:07.480 --> 0:11:10.040 Now that transition is a little more subtle than first 0:11:10.160 --> 0:11:14.719 order transitions. It involves the thermal expansion and heat capacity 0:11:14.800 --> 0:11:19.240 of a material, so it wouldn't be as obvious to 0:11:19.360 --> 0:11:24.040 casual observation on a microscopic level, but there would still 0:11:24.080 --> 0:11:29.720 be differences with the thermodynamics of the material, so we still 0:11:29.720 --> 0:11:32.319 would say the glass is a solid, not a liquid. 0:11:32.440 --> 0:11:35.120 All right, I'm done with glass now, I promise. I 0:11:35.160 --> 0:11:37.400 had to go on that little track just because it 0:11:37.440 --> 0:11:39.439 was related to the stuff I was talking about, and 0:11:39.840 --> 0:11:42.600 I get really irritated seeing that one myth passed around 0:11:42.600 --> 0:11:44.840 as fact. So now you know, if you ever go 0:11:44.920 --> 0:11:49.120 through a tour and the tour guide says and the 0:11:49.160 --> 0:11:51.520 reason that the windows are thicker at the bottom is 0:11:51.520 --> 0:11:53.920 because glass flows over the course of hundreds of years. 0:11:54.200 --> 0:11:58.760 You can raise your hand and say, well, actually and 0:11:58.840 --> 0:12:00.800 tell them Josh Clark sent because I don't want that 0:12:00.880 --> 0:12:02.839 kind of burden on me. I like being able to 0:12:02.880 --> 0:12:07.800 take tours. Anyway, Let's get back to viscosity in general. So, 0:12:07.920 --> 0:12:11.320 like I said earlier, viscosity is due to internal friction 0:12:11.520 --> 0:12:14.559 of a liquid. And you might think that that sounds weird, 0:12:14.640 --> 0:12:17.199 like how can a liquid have friction inside of it? 0:12:17.480 --> 0:12:21.600 But we're talking about liquid specifically that have like molecules, 0:12:21.600 --> 0:12:24.240 and those molecules can have a tendency to resist getting 0:12:24.320 --> 0:12:28.160 by each other. So some molecules are more resistant to 0:12:29.320 --> 0:12:31.880 slip and by each other than others. Or a liquid 0:12:31.880 --> 0:12:34.280 could actually have particles that are suspended in it. It could 0:12:34.280 --> 0:12:37.959 be a suspension, which is different than just a pure liquid. 0:12:39.160 --> 0:12:43.439 But if it's a suspension, it's got particles suspended within 0:12:44.080 --> 0:12:48.240 the liquid at some level of density, right, Like some 0:12:48.640 --> 0:12:50.559 may be a pretty weak suspension where you don't have 0:12:50.600 --> 0:12:55.760 a whole lot, but others could have a greater density 0:12:55.800 --> 0:13:00.320 of particles inside a suspension of fluid. Make chocolate bars, say, 0:13:00.800 --> 0:13:04.640 and you're laying out melted chocolate into the mold for 0:13:04.720 --> 0:13:07.640 the chocolate bars, and it clogs up, and you have 0:13:07.679 --> 0:13:10.520 to stop production and clean out the clog and get 0:13:10.559 --> 0:13:13.240 everything back up to temperature and start it all over again. 0:13:13.679 --> 0:13:17.880 It's time consuming and expensive when that happens. So one 0:13:17.920 --> 0:13:21.600 solution to preventing it from happening is dilute the cacao 0:13:22.080 --> 0:13:25.280 more so that those particles don't clump up as much 0:13:25.320 --> 0:13:31.559 because there's a less dense CACW component in the fluid. 0:13:32.320 --> 0:13:36.160 That essentially means replacing CaCO with something else, typically something 0:13:36.240 --> 0:13:40.640 that is less viscous, like that oil that fat essentially, 0:13:41.559 --> 0:13:44.760 so you usually add more fat to the recipe so 0:13:44.800 --> 0:13:48.000 you get the more fat but less cacw. However, it 0:13:48.080 --> 0:13:52.360 ends up flowing better and creates the chocolate bars that 0:13:52.400 --> 0:13:56.200 you want without creating the clogs. But it's not necessarily 0:13:56.280 --> 0:13:59.199 the best product you could create. It's just the most 0:13:59.200 --> 0:14:04.360 convenient upon the method of production. So that's where this 0:14:04.400 --> 0:14:08.280 alternative solution comes in. If you could change the shape 0:14:08.480 --> 0:14:11.360 of those cacal particles in the fluid so that they 0:14:11.440 --> 0:14:16.200 packed together more effectively, you would reduce that viscosity, that 0:14:16.360 --> 0:14:20.720 internal friction of the fluid. So imagine you've got one 0:14:20.760 --> 0:14:25.160 of those inflated rubber balls, like a kickball or something. Now, 0:14:25.200 --> 0:14:28.680 imagine that you're able to grab hold on either side 0:14:28.920 --> 0:14:33.000 of this ball and pull it outward so that you're 0:14:33.160 --> 0:14:37.000 elongating it. Now it would become a more of an 0:14:37.000 --> 0:14:42.280 oval shape, or as the researchers at Temple University called them, 0:14:42.640 --> 0:14:48.120 prolate spheroids. Now, the interesting thing about these prolate spheroids 0:14:48.240 --> 0:14:50.800 is if you align them in the direction of the 0:14:50.840 --> 0:14:54.160 flow of chocolate, you can pack more of them together. 0:14:54.240 --> 0:14:57.240 They have these elongated sides, and they will fit together 0:14:57.360 --> 0:15:01.520 much more snuggly. You can create chains of them, and 0:15:02.200 --> 0:15:05.800 chocolate would flow much more readily. But how do you 0:15:06.040 --> 0:15:09.680 change the shape of those cacal particles. What is it 0:15:09.720 --> 0:15:13.280 that you could do to make them actually assume a 0:15:13.360 --> 0:15:19.600 different shape than their natural globular ball like shape. This 0:15:19.760 --> 0:15:24.240 is where electric fields come in. We're going to talk 0:15:24.280 --> 0:15:27.240 about applying magnetic or electric fields to a fluid to 0:15:27.360 --> 0:15:30.960 change its viscosity. But first, this doesn't work with every fluid. 0:15:32.000 --> 0:15:35.360 Not every fluid reacts to electric fields and magnetic fields 0:15:35.400 --> 0:15:38.240 in a way that will alter its viscosity. But it 0:15:38.280 --> 0:15:41.640 does work in fluids that have certain non conducting or 0:15:41.720 --> 0:15:47.760 weakly conducting particles suspended in an electrically insulating fluid. Now 0:15:47.840 --> 0:15:53.240 we call this a special type of liquid electroreeological fluid 0:15:53.760 --> 0:15:56.880 electroheological fluids. That essentially means that when you apply an 0:15:56.920 --> 0:16:00.880 electric or magnetic field to such a fluid, it changes 0:16:01.000 --> 0:16:04.840 its viscosity. Sometimes we also call them smart fluids, but 0:16:04.880 --> 0:16:08.360 more about that in a bit. Now. Interestingly, the property 0:16:08.480 --> 0:16:12.360 was completely discovered by chance. There was an inventor named 0:16:12.440 --> 0:16:16.600 Willis Winslow who observed the effect in the nineteen forties, 0:16:16.720 --> 0:16:21.080 and he actually patented it in nineteen forty seven. Now, 0:16:21.120 --> 0:16:24.840 for this reason, we sometimes call this effect of changing 0:16:24.880 --> 0:16:29.920 an electroheological fluids viscosity the Winslow effect, And I'll mostly 0:16:29.960 --> 0:16:32.680 be using that term from here on out, because there's 0:16:32.680 --> 0:16:33.960 only so many times I'm going to be able to 0:16:34.000 --> 0:16:38.440 say electroreeological before my mouth just decides to rebel against 0:16:38.440 --> 0:16:41.280 the rest of me and march out the door. And 0:16:41.360 --> 0:16:47.440 as entertaining as that would be, I kind of need it. Well, 0:16:48.120 --> 0:16:51.680 we know that the candy man can make better chocolate, 0:16:51.960 --> 0:16:54.960 but how could tech make better chocolate? I guess we'll 0:16:55.360 --> 0:17:10.560 conclude that when we come back from these messages. All right, 0:17:10.640 --> 0:17:14.040 So Applying an electric or magnetic field to such a 0:17:14.040 --> 0:17:20.359 fluid changes that fluid's viscosity within melliseconds like it's practically instantaneous, 0:17:21.119 --> 0:17:24.199 And if you remove the field, the particles in the 0:17:24.200 --> 0:17:27.199 fluid will snap back to their original shape, to the 0:17:27.240 --> 0:17:30.399 fluid's viscosity will return to what it normally would be. 0:17:30.800 --> 0:17:34.440 So the change isn't permanent. It only persists as long 0:17:34.560 --> 0:17:38.840 as the respective field persists, which is super cool because 0:17:38.880 --> 0:17:42.960 you can do these temporary changes that are really useful 0:17:43.040 --> 0:17:45.639 in specific situations and then have it go back to 0:17:45.720 --> 0:17:49.080 normal and it's like it never happened in the first place. 0:17:50.520 --> 0:17:52.600 But one thing to keep in mind is the direction 0:17:53.000 --> 0:17:57.359 of the electric or magnetic field is critically important when 0:17:57.560 --> 0:18:00.439 you want to make a particular effect. So in the 0:18:00.440 --> 0:18:05.160 case of chocolate, if you apply the electric field perpendicular 0:18:05.320 --> 0:18:08.920 to the direction of flow, you will actually increase the 0:18:09.040 --> 0:18:12.040 viscosity of the chocolate. You will make it thicker, more 0:18:12.080 --> 0:18:16.320 like a gel. Melted chocolate will turn into this kind 0:18:16.320 --> 0:18:19.600 of thick gel. It'll otherwise have all the same properties 0:18:19.600 --> 0:18:24.680 that had before, but that viscosity will increase dramatically. However, 0:18:24.920 --> 0:18:27.159 if you were to apply that electric field in the 0:18:27.240 --> 0:18:31.560 direction of the flow of chocolate. Then you would decrease 0:18:31.600 --> 0:18:34.199 the viscosity of chocolate and it will flow more freely 0:18:34.280 --> 0:18:38.920 at that point. Now this makes some sense because imagine 0:18:38.960 --> 0:18:46.920 that you have these elongated ovals, these prolate spheroids. Right. 0:18:47.800 --> 0:18:50.919 If you stand them vertically, then you could imagine them 0:18:50.960 --> 0:18:54.040 slipping through a pipe very easily. If you laid them 0:18:54.040 --> 0:18:59.800 out horizontally, you could imagine them ending up like blocking 0:19:00.119 --> 0:19:03.160 pipe easily. Because it's like trying to fit a long 0:19:03.280 --> 0:19:05.960 stick through a narrow doorway. If you don't turn it 0:19:05.960 --> 0:19:08.440 the right way, you're just gonna hit against the door. 0:19:08.680 --> 0:19:11.040 This is making me think of my dog, Timbalt, who 0:19:11.320 --> 0:19:14.240 has done this on numerous occasions. He just he can't 0:19:14.240 --> 0:19:16.880 get it through his little doggy mind that he needs 0:19:16.920 --> 0:19:19.199 to turn the stick vertical in order to move it 0:19:19.280 --> 0:19:22.840 through a doorway. He just wants to charge ahead full 0:19:22.920 --> 0:19:28.920 steam with the stick horizontal. In many other ways, He's 0:19:28.960 --> 0:19:34.440 an intelligent dog, so we forgive him this lapse of judgment. Anyway, 0:19:34.680 --> 0:19:37.520 the chocolate on a molecular level is essentially the same thing. 0:19:37.920 --> 0:19:41.159 If you are applying this electric field perpendicular to the 0:19:41.160 --> 0:19:45.440 flow of chocolate, then you get this much thicker mixture. 0:19:45.480 --> 0:19:49.760 And an interesting side note, the electro rheological properties of 0:19:49.800 --> 0:19:53.040 chocolate aren't a new discovery, right. I mean, I covered 0:19:53.040 --> 0:19:57.520 this story for house Stuffworks now because there was a 0:19:57.600 --> 0:20:01.800 new application of this property with chocolate. But we actually 0:20:01.840 --> 0:20:04.840 knew that chocolate would react this way already, at least 0:20:04.880 --> 0:20:08.439 to the point of increasing the viscosity, because back in 0:20:08.520 --> 0:20:12.520 nineteen ninety six there was a Michigan State University grad 0:20:12.560 --> 0:20:15.719 student who observed the Winslow effect on chocolate. And his 0:20:15.840 --> 0:20:19.879 name is doctor Christopher R. Daubert, and as professor, doctor 0:20:20.000 --> 0:20:23.760 James Steph worked with him. They both conducted experiments on 0:20:23.880 --> 0:20:27.720 liquid chocolate and observed the Winslow effect. Now, in that experiment, 0:20:27.800 --> 0:20:31.600 Daubert was again increasing the viscosity, not decreasing it, so 0:20:31.680 --> 0:20:34.439 he was turning chocolate into that thicker gel. That the 0:20:34.480 --> 0:20:38.560 liquid chocolate into thick gel. It wasn't until recently that 0:20:38.640 --> 0:20:42.119 we saw someone try and do the opposite. So that 0:20:42.160 --> 0:20:46.399 brings us to the Temple University experiment. So you had 0:20:46.440 --> 0:20:50.119 these researchers. They had worked on crude oil and decreased 0:20:50.119 --> 0:20:53.160 the viscosity of crude oil, which is a huge thing 0:20:53.240 --> 0:20:56.960 for the oil industry to be able to move oil 0:20:57.040 --> 0:21:02.360 more effectively without the fear of clogs or viscosity screwing 0:21:02.480 --> 0:21:06.240 up things that had been planned ahead of time. They 0:21:06.280 --> 0:21:08.040 wanted to see if they could, in fact use a 0:21:08.080 --> 0:21:12.200 similar approach to have liquid chocolate move more smoothly through 0:21:12.200 --> 0:21:17.280 a system, so that manufacturers could save money by not 0:21:17.320 --> 0:21:20.080 having to worry about cleaning up clogs and shutting down 0:21:20.080 --> 0:21:25.000 production for maintenance. So they had to test this hypothesis 0:21:26.040 --> 0:21:28.719 that an electric field directed in the flow of liquid 0:21:28.800 --> 0:21:32.920 chocolate would reduce viscosity. So they built a cool chocolate 0:21:33.040 --> 0:21:38.920 zapping gadget. It's not really a zapper, it's a it's 0:21:39.000 --> 0:21:43.000 kind of not entirely accurate, but I like the idea 0:21:43.080 --> 0:21:45.879 of using electricity to zap chocolate to make it better. 0:21:46.480 --> 0:21:49.680 That's just an oversimplification of what happened, but that's okay. 0:21:49.880 --> 0:21:54.280 I'll explain to you what was actually going on. They 0:21:54.320 --> 0:21:56.920 built this thing where it starts with a bit of 0:21:56.960 --> 0:21:59.480 a melting chamber. You can just think of it as 0:21:59.520 --> 0:22:03.800 like a a pot. It could even be a glass vial. Really, 0:22:03.800 --> 0:22:08.040 it could just be any little container that can hold chocolate. 0:22:08.720 --> 0:22:11.640 They put the chocolate in the container, and they cover 0:22:11.720 --> 0:22:16.560 the container, sealing it shut. They added compressed nitrogen gas 0:22:16.760 --> 0:22:20.080 into the chamber simply really to just increase the pressure 0:22:20.880 --> 0:22:23.840 inside the chamber itself. The chamber was heated so that 0:22:23.880 --> 0:22:26.840 you had chocolate melting into a liquid. There was a 0:22:26.840 --> 0:22:29.080 therma couple in there to make sure that the temperature 0:22:29.160 --> 0:22:32.520 was correct so that the chocolate would not overheat or 0:22:32.560 --> 0:22:36.080 cool down so much that it becomes solid again. And 0:22:36.119 --> 0:22:39.520 then the base of this container was essentially a drain, 0:22:40.600 --> 0:22:43.679 so there's like a hole at the bottom of the 0:22:43.720 --> 0:22:47.080 container that liquid chocolate could flow through. Attached to that 0:22:47.240 --> 0:22:49.399 was a tube, and inside the tube they put a 0:22:49.440 --> 0:22:55.359 series of metal mesh screens, and the screens were what 0:22:55.600 --> 0:22:59.840 generated the electric field. They had electricity running to those 0:23:00.040 --> 0:23:03.240 screens and creating electric field that way in the direction 0:23:03.320 --> 0:23:05.960 of the flow of chocolate, so the chocolate would end 0:23:06.040 --> 0:23:11.399 up flowing very smoothly through the tube and didn't have 0:23:11.440 --> 0:23:14.439 any issues. At the other end, they had another vessel 0:23:14.840 --> 0:23:18.320 container that the liquid chocolate would flow into, it would 0:23:18.320 --> 0:23:22.359 cool down solidify. So once that liquid chocolate flowed through 0:23:22.480 --> 0:23:26.520 into the collecting vessel and once it was free of 0:23:26.560 --> 0:23:30.080 the electric field, the cacal particles they went back to 0:23:30.119 --> 0:23:34.600 their original shape immediately. Again, they didn't have to transform 0:23:34.680 --> 0:23:38.200 or anything. It wasn't a gradual process. They boop moved 0:23:38.200 --> 0:23:41.600 back into those globe shapes that they typically are in, 0:23:42.760 --> 0:23:46.640 and the chocolate cooled and solidified and was, to all 0:23:46.640 --> 0:23:50.000 intents and purposes, indistinguishable from the chocolate that was being 0:23:50.040 --> 0:23:54.479 fed through at the top at that top chamber. So 0:23:54.520 --> 0:23:58.879 they were able to reduce the viscosity of the flowing 0:23:58.960 --> 0:24:03.919 chocolate and to the point where it was no there 0:24:03.960 --> 0:24:07.240 were no issues of clogging, it was perfectly fine. So 0:24:07.280 --> 0:24:09.720 they were able to prove that their hypothesis was correct, 0:24:09.760 --> 0:24:14.000 that in fact, this electric field applied in this way 0:24:14.560 --> 0:24:21.119 would decrease chocolate's viscosity. Hooray. But there's more to it 0:24:21.160 --> 0:24:23.520 than that. So this experiment was not just a success. 0:24:23.600 --> 0:24:26.640 The researchers actually realized that it had a lot more 0:24:26.640 --> 0:24:31.360 implications than just having chocolate flow freely through a machine. 0:24:32.920 --> 0:24:35.560 That again, the reason why chocolate has such a relatively 0:24:35.680 --> 0:24:39.600 high fat content is to create that oily fluid to 0:24:39.840 --> 0:24:44.040 reduce viscosity, to have the cacao particles suspended within it 0:24:44.560 --> 0:24:48.480 at a density that's low enough so that you're not 0:24:48.880 --> 0:24:52.200 likely to clog up the machines. But if you use 0:24:52.280 --> 0:24:57.240 this approach, if you use the electric fields to reduce viscosity, 0:24:57.640 --> 0:25:01.240 you don't need as much oil or fat in your 0:25:01.320 --> 0:25:04.679 chocolate content. You could actually start with a recipe that 0:25:04.760 --> 0:25:09.240 has less fat in it, and the electric fields would 0:25:09.280 --> 0:25:12.320 take care of the viscosity problem, so you don't have 0:25:12.520 --> 0:25:15.200 to have as much fat there. That also means you 0:25:15.200 --> 0:25:18.040 could have more cacal in your mixture. It could be 0:25:18.760 --> 0:25:23.600 a higher proportion of the overall recipe. So they found 0:25:23.640 --> 0:25:26.520 that they could reduce the fat content in certain types 0:25:26.560 --> 0:25:30.399 of chocolate by as much as twenty percent and still 0:25:30.400 --> 0:25:34.679 have no negative impact on the fluid's viscosity. Now, it 0:25:34.760 --> 0:25:37.880 depends on what type of chocolate they were using. They 0:25:37.920 --> 0:25:43.160 were actually using name brand chocolates, you know, like chocolate bars. 0:25:43.880 --> 0:25:46.600 They would try different types and depending on the type, 0:25:46.600 --> 0:25:51.280 they could actually end up removing up to twenty percent 0:25:51.320 --> 0:25:54.639 of the fat in the mixture and still have the 0:25:54.680 --> 0:26:00.000 chocolate flow without any problems. And beyond that, the researchers 0:26:00.119 --> 0:26:03.760 said that people who are tasting the chocolate afterward, because 0:26:03.840 --> 0:26:05.440 keep in mind, other than the fact that there was 0:26:05.520 --> 0:26:08.000 less fat in it, there was really no difference between 0:26:08.040 --> 0:26:11.159 the original chocolate and the end result. They said that 0:26:11.200 --> 0:26:15.120 the end result chocolate actually tasted better to them. He said, 0:26:15.119 --> 0:26:18.320 I had a more intense cacw flavor. It was more 0:26:18.440 --> 0:26:23.800 chocolatey than the original chocolate. Now that could be just subjective, 0:26:24.000 --> 0:26:27.600 or it could be purely psychological, but it's not outside 0:26:27.640 --> 0:26:33.840 the realm of possibility that by increasing the proportion of 0:26:34.000 --> 0:26:38.600 chocolate of cacao in your mixture because you've removed some 0:26:38.680 --> 0:26:42.200