1 00:00:01,880 --> 00:00:07,640 Speaker 1: Welcome to Brainstuff, a production of iHeartRadio. Hey brain Stuff 2 00:00:07,680 --> 00:00:12,119 Speaker 1: Lauren Volgebon Here. You might think that you try to 3 00:00:12,160 --> 00:00:16,640 Speaker 1: avoid microorganisms in your food because bacteria and fungi cause 4 00:00:16,680 --> 00:00:20,040 Speaker 1: food to spoil. But the truth is we wouldn't have 5 00:00:20,120 --> 00:00:26,760 Speaker 1: a lot of the world's favorite foods and beverages like coffee, chocolate, vanilla, cheese, bread, beer, 6 00:00:26,840 --> 00:00:30,240 Speaker 1: and cured meats, just to name a few, without fermentation, 7 00:00:30,960 --> 00:00:36,400 Speaker 1: which involves the intentional use of microorganisms to transform food. 8 00:00:36,760 --> 00:00:39,760 Speaker 1: The line between spoiling and fermentation is a muddy one, 9 00:00:39,880 --> 00:00:44,960 Speaker 1: but a distinction humans have been fuzzing with for millennia. Generally, 10 00:00:45,040 --> 00:00:48,080 Speaker 1: when we say that food has spoiled, what we technically 11 00:00:48,159 --> 00:00:51,120 Speaker 1: mean is that microbes have started eating it before we've 12 00:00:51,159 --> 00:00:54,240 Speaker 1: had a chance to, and that they've made the texture 13 00:00:54,480 --> 00:00:58,440 Speaker 1: and or flavor unpleasant to us. And if those microbes 14 00:00:58,440 --> 00:01:01,520 Speaker 1: are pathogenic, eating that food could even make us sick. 15 00:01:02,840 --> 00:01:07,360 Speaker 1: When we ferment food, we're employing helpful, nonpathogenic microbes to 16 00:01:07,680 --> 00:01:11,720 Speaker 1: spoil it on purpose before harmful microbes can get to it. 17 00:01:13,400 --> 00:01:15,920 Speaker 1: For the article, this episode is based on How Stuff Work. 18 00:01:16,000 --> 00:01:18,679 Speaker 1: Spoke with sand Or Cats, a teacher and author of 19 00:01:18,720 --> 00:01:24,319 Speaker 1: several books about fermentation. He said, what microbiology has illuminated 20 00:01:24,560 --> 00:01:27,360 Speaker 1: is that all the plants and animal products that make 21 00:01:27,440 --> 00:01:31,800 Speaker 1: up our food are inevitably populated by a diversity of microorganisms. 22 00:01:32,520 --> 00:01:36,959 Speaker 1: Fermentation involves encouraging the growth of some microorganisms, ones that 23 00:01:37,000 --> 00:01:40,959 Speaker 1: make our food more stable, more delicious, more nutritious, safer, 24 00:01:41,360 --> 00:01:45,600 Speaker 1: less toxic or alcoholic, and thereby prevent the growth of 25 00:01:45,640 --> 00:01:48,760 Speaker 1: the ones that can decompose our food or make us sick. 26 00:01:50,600 --> 00:01:54,800 Speaker 1: Every known culinary tradition in the world uses fermentation in 27 00:01:54,840 --> 00:01:59,400 Speaker 1: some way or another. Humans began using fermentation to brew beer, 28 00:01:59,600 --> 00:02:02,960 Speaker 1: preserve food, and make their food tasty, and render toxic 29 00:02:03,000 --> 00:02:07,240 Speaker 1: things edible millennia before Louis Pasteur proved that living cells 30 00:02:07,280 --> 00:02:12,679 Speaker 1: were responsible for fermentation. Akatz said the oldest examples of 31 00:02:12,720 --> 00:02:16,440 Speaker 1: fermentation in the archaeological record are from about ten thousand 32 00:02:16,480 --> 00:02:19,640 Speaker 1: years ago in China, though I would argue that tells 33 00:02:19,680 --> 00:02:21,720 Speaker 1: us more about the history of pottery than the history 34 00:02:21,720 --> 00:02:25,959 Speaker 1: of fermentation. Presumably, the cultural practice of fermentation is older 35 00:02:26,000 --> 00:02:30,200 Speaker 1: than that using pits of the ground, gourds, animal membranes, wood, 36 00:02:30,360 --> 00:02:36,240 Speaker 1: or other biodegradable materials. It's no surprise that fermentation can 37 00:02:36,280 --> 00:02:38,840 Speaker 1: be traced back to around the same time as humans 38 00:02:38,880 --> 00:02:43,000 Speaker 1: began developing communities around agriculture. In order for it to 39 00:02:43,160 --> 00:02:45,440 Speaker 1: make sense for us to invest all our time and 40 00:02:45,560 --> 00:02:49,080 Speaker 1: energy into growing plants and livestock for food instead of 41 00:02:49,120 --> 00:02:51,960 Speaker 1: hunting and gathering, humans would have had to come up 42 00:02:52,000 --> 00:02:55,280 Speaker 1: with a strategy for storing and preserving food so that 43 00:02:55,320 --> 00:02:57,960 Speaker 1: the harvest of a few weeks could last the community 44 00:02:58,080 --> 00:03:03,520 Speaker 1: many months. Also, basically every culture in the world has 45 00:03:03,560 --> 00:03:08,120 Speaker 1: figured out how to ferment sugars into alcohol. It's possible 46 00:03:08,160 --> 00:03:11,720 Speaker 1: that our primate ancestors understood the party inducing effects of 47 00:03:11,760 --> 00:03:13,679 Speaker 1: eating a bunch of fermented fruit that they found on 48 00:03:13,720 --> 00:03:17,120 Speaker 1: the ground. It helps that the yeasts that turn sugars 49 00:03:17,120 --> 00:03:20,040 Speaker 1: into alcohol grow wild in the air and on the 50 00:03:20,040 --> 00:03:23,240 Speaker 1: skins of many fruit. All humans had to do was 51 00:03:23,280 --> 00:03:27,840 Speaker 1: figure out how to do this on purpose. The word 52 00:03:27,880 --> 00:03:31,240 Speaker 1: ferment comes from the Latin word for boiling or rising, 53 00:03:31,560 --> 00:03:34,400 Speaker 1: which makes perfect sense if you've ever seen beer brewing 54 00:03:34,680 --> 00:03:38,480 Speaker 1: or bread dough rising. The bubbles and beer and pockets 55 00:03:38,480 --> 00:03:40,800 Speaker 1: of air and bread both come from the action of 56 00:03:40,880 --> 00:03:46,360 Speaker 1: yeasts living. The applied science of zymology is the study 57 00:03:46,400 --> 00:03:49,800 Speaker 1: of how microorganisms ferment these stuff around us. Oh, what 58 00:03:49,920 --> 00:03:53,760 Speaker 1: the biochemical processes are which specific organisms are doing it, 59 00:03:54,120 --> 00:03:56,760 Speaker 1: and how this works all over the world, including in 60 00:03:56,800 --> 00:04:01,280 Speaker 1: our foods. There are three base types of fermentation that 61 00:04:01,320 --> 00:04:03,960 Speaker 1: can happen in the foods and drinks we enjoy every day. 62 00:04:05,120 --> 00:04:08,360 Speaker 1: Alcoholic fermentation has been a fan favorite for millennia. It 63 00:04:08,560 --> 00:04:12,080 Speaker 1: uses yeasts to convert sugars in plants like grains or 64 00:04:12,120 --> 00:04:16,240 Speaker 1: fruit into ethanol, carbon dioxide, and other byproducts, some of 65 00:04:16,240 --> 00:04:21,880 Speaker 1: which we experience as flavors. Humans invented alcoholic beverages before 66 00:04:21,920 --> 00:04:28,320 Speaker 1: we invented the wheel. Then there's acetic acid fermentation, which 67 00:04:28,320 --> 00:04:32,640 Speaker 1: happens after yeasts finish their alcoholic fermentation and acetic acid 68 00:04:32,680 --> 00:04:38,440 Speaker 1: bacteria take over. These bacteria ferment sugars and ethanol into acids, 69 00:04:38,760 --> 00:04:44,000 Speaker 1: are resulting in things like vinegar and kombucha. Last, but 70 00:04:44,160 --> 00:04:48,159 Speaker 1: not least, there's lactic acid fermentation, which is the microbial 71 00:04:48,240 --> 00:04:51,280 Speaker 1: magic behind so many of our favorite foods, from sour 72 00:04:51,360 --> 00:04:55,960 Speaker 1: dough bread to kimchi to yogurt, plus many types of cheese. 73 00:04:56,240 --> 00:05:01,080 Speaker 1: Lactic acid bacteria convert simple carbohydrates into lactic acid, a 74 00:05:01,200 --> 00:05:05,000 Speaker 1: process that turns sweet things sour, which is what gives 75 00:05:05,080 --> 00:05:10,159 Speaker 1: all of the above foods their characteristic kick a note 76 00:05:10,200 --> 00:05:13,240 Speaker 1: that often the fermented foods we eat rely on more 77 00:05:13,240 --> 00:05:16,839 Speaker 1: than one of these processes. Some beers are flavored with 78 00:05:16,880 --> 00:05:20,599 Speaker 1: help from lactic acid bacteria. Pickles can be made either 79 00:05:20,640 --> 00:05:24,679 Speaker 1: with lactic acid bacteria or vinegar, or a combination of both, 80 00:05:25,640 --> 00:05:28,320 Speaker 1: and things like chocolate and coffee get some of their 81 00:05:28,400 --> 00:05:34,240 Speaker 1: characteristic flavor from a combination of all three. But these 82 00:05:34,279 --> 00:05:38,719 Speaker 1: processes don't just make food tart or tasty or alcoholic. 83 00:05:39,320 --> 00:05:42,960 Speaker 1: They also make them last longer. You know, cheese stays 84 00:05:43,000 --> 00:05:46,279 Speaker 1: good longer than milk. But part of what's so cool 85 00:05:46,320 --> 00:05:50,200 Speaker 1: about our ancestors using fermentation on food is that, thousands 86 00:05:50,240 --> 00:05:54,080 Speaker 1: of years before we understood what microbes or nutrients are, 87 00:05:54,600 --> 00:06:00,360 Speaker 1: we were using microbes to unlock nutrients. The microorganisms that 88 00:06:00,440 --> 00:06:04,880 Speaker 1: ferment our food essentially break down things like carbohydrates, proteins, 89 00:06:05,000 --> 00:06:07,560 Speaker 1: and chemical bonds in our food before we eat it, 90 00:06:08,160 --> 00:06:11,520 Speaker 1: in some cases, making it more easily digested or its 91 00:06:11,600 --> 00:06:16,560 Speaker 1: nutrients more bioavailable. That's why someone with the lactose intolerance 92 00:06:16,640 --> 00:06:19,839 Speaker 1: might be able to eat in aged cheese with no issue. 93 00:06:20,200 --> 00:06:23,239 Speaker 1: The lactose or milk sugar will have been almost entirely 94 00:06:23,279 --> 00:06:28,159 Speaker 1: broken down by bacteria. During the aging process. Fermentation also 95 00:06:28,200 --> 00:06:31,479 Speaker 1: generates additional bee vitamins in many foods and cave vitamins 96 00:06:31,480 --> 00:06:36,200 Speaker 1: in some. Furthermore, some foods can only be made edible 97 00:06:36,240 --> 00:06:40,920 Speaker 1: at all through fermentation. The microorganisms take potentially toxic to 98 00:06:41,000 --> 00:06:45,240 Speaker 1: us compounds and digest them into harmless or even beneficial forms, 99 00:06:45,680 --> 00:06:49,440 Speaker 1: rendering foods that could otherwise be poisonous or irritating safe 100 00:06:49,440 --> 00:06:52,560 Speaker 1: to eat. One example of this can be found in 101 00:06:52,560 --> 00:06:56,080 Speaker 1: cassava tubers. They contain high levels of cyanide when they're 102 00:06:56,080 --> 00:06:59,640 Speaker 1: harvested and require fermentation to make them safe to eat. 103 00:07:00,680 --> 00:07:03,960 Speaker 1: One popular health claim made about some fermented foods is 104 00:07:03,960 --> 00:07:07,520 Speaker 1: that they contain probiotics, which are live microorganisms that are 105 00:07:07,560 --> 00:07:10,200 Speaker 1: supposed to help our digestive systems and or our gut 106 00:07:10,200 --> 00:07:15,200 Speaker 1: microbiome function better. Unfortunately, science hasn't been able to prove 107 00:07:15,240 --> 00:07:19,080 Speaker 1: those claims yet. Our bodies are complicated and more research 108 00:07:19,120 --> 00:07:24,120 Speaker 1: is necessary there. As with any food or drink, we 109 00:07:24,200 --> 00:07:27,120 Speaker 1: hear brain stuff think that you should consume fermented products 110 00:07:27,200 --> 00:07:30,760 Speaker 1: if you like them. Katz said certain ferments, such as 111 00:07:30,760 --> 00:07:33,840 Speaker 1: strong cheeses, are edgy, and that some people find them 112 00:07:33,880 --> 00:07:37,440 Speaker 1: compellingly delicious, while others think that they're disgusting and are 113 00:07:37,480 --> 00:07:42,160 Speaker 1: reminded of decomposition and death. Science offers us no sharp 114 00:07:42,160 --> 00:07:47,160 Speaker 1: dividing line between fermentation and spoilage. In most cases, it's obvious, 115 00:07:47,440 --> 00:07:56,679 Speaker 1: but in certain cases it's culturally determined and subjective. Today's 116 00:07:56,680 --> 00:08:00,360 Speaker 1: episode is based on the article food Fermentation How microorganisms 117 00:08:00,400 --> 00:08:03,880 Speaker 1: make Food Delicious on HowStuffWorks dot com, written by Jesselynshields. 118 00:08:04,520 --> 00:08:06,920 Speaker 1: For lots more about how food fermentation works, check out 119 00:08:06,920 --> 00:08:10,720 Speaker 1: my other podcast Saver brain Stuff is production of iHeartRadio 120 00:08:10,760 --> 00:08:13,000 Speaker 1: and partnership with how stuffworks dot Com, and is produced 121 00:08:13,040 --> 00:08:15,840 Speaker 1: by Tyler klang A. Four more podcasts my heart Radio, 122 00:08:16,040 --> 00:08:19,119 Speaker 1: visit the iHeartRadio app, Apple Podcasts, or wherever you listen 123 00:08:19,160 --> 00:08:20,160 Speaker 1: to your favorite shows.