WEBVTT - How Does Baker's Yeast Work? 0:00:01.800 --> 0:00:06.960 Welcome to brain Stuff, a production of iHeart Radio, Hey 0:00:07.080 --> 0:00:11.119 rain Stuff, Lauren bogobam here. If you're making a raised 0:00:11.160 --> 0:00:13.840 baked good, there are a few ways you can achieve 0:00:13.920 --> 0:00:18.079 that height. Quick breads like muffins use chemical leaveners like 0:00:18.120 --> 0:00:21.760 baking powder. Cookies, bars, and cakes often use whipped eggs 0:00:21.840 --> 0:00:24.720 or creamed butter and sugar with tiny pockets of air 0:00:24.880 --> 0:00:28.960 carefully beaten in. But many breads and rolls use a 0:00:29.000 --> 0:00:34.760 living ingredient to get that rise. Yeast. This single celled 0:00:34.880 --> 0:00:39.760 organism is integral too many a baking process, transforming a solid, 0:00:39.840 --> 0:00:44.400 dense ball of dough into a soft, risen loaf. But 0:00:44.640 --> 0:00:47.159 not all yeast is the same. There are more than 0:00:47.240 --> 0:00:50.519 one thousand, five hundred recognized species of yeast in the world, 0:00:50.720 --> 0:00:53.519 with the first known types dating back hundreds of millions 0:00:53.520 --> 0:00:58.480 of years. Today's primary baking yeast species is Sacchara mices 0:00:58.560 --> 0:01:02.720 sera vizier. It's responsible for two of the tastiest yeast 0:01:02.720 --> 0:01:07.720 related food products out there, bread and beer. But how 0:01:07.760 --> 0:01:11.360 can a tiny organism only visible with the microscope create 0:01:11.400 --> 0:01:14.800 two of the world's most beloved meal time staples, and 0:01:15.120 --> 0:01:19.680 is baking with yeast as intimidating as it seems. Let's 0:01:19.680 --> 0:01:22.720 back up a step. A yeast is a single celled 0:01:22.840 --> 0:01:27.640 fungus related to mushrooms. Yeast used by bakers, s seravisier 0:01:28.040 --> 0:01:33.440 is known as a sugar eating fungus. Simple sugars like sucrose, fructose, glucose, 0:01:33.480 --> 0:01:37.679 and maltose helped the yeast thrive, and once metabolized, the 0:01:37.720 --> 0:01:42.840 sugars ultimately lead to risen bread. The process is known 0:01:42.920 --> 0:01:48.200 as alcoholic fermentation. When you mix flour, water, and yeast together, 0:01:48.640 --> 0:01:51.480 the yeast eats these simple sugars in the flour and 0:01:51.800 --> 0:01:56.080 poops alcohol, carbon dioxide bubbles and molecules that we consider 0:01:56.160 --> 0:02:00.600 flavor into the doughy mix. The carbon dioxide bowls can't 0:02:00.720 --> 0:02:04.639 escape the elastic dough, so instead they cause it to rise. 0:02:05.520 --> 0:02:08.240 When you bake that dough, you're firming up the matrix 0:02:08.280 --> 0:02:12.000 of proteins like gluten in the dough around those air bubbles, 0:02:12.040 --> 0:02:16.079 resulting in what we know as fluffy, tender yeast leavened bread. 0:02:18.200 --> 0:02:21.120 There are two primary types of baker's east on the market. 0:02:21.480 --> 0:02:25.239 Active yeast and instant yeast. Both come to you dried 0:02:25.280 --> 0:02:29.200 and granulated in small packets, but each brings something slightly 0:02:29.200 --> 0:02:32.920 different to the table. Active yeast must be activated with 0:02:32.960 --> 0:02:36.520 warm water before using instant yeast can go straight into 0:02:36.600 --> 0:02:40.720 your dough and get to work. The fermentation process with 0:02:40.800 --> 0:02:44.600 active dry yeast takes longer than with instant yeast. This 0:02:44.680 --> 0:02:47.320 can lead to subtly different flavors and breads made with 0:02:47.360 --> 0:02:51.840 active yeast over instant. For the article this episode is 0:02:51.840 --> 0:02:54.360 based on, has to Work, spoke of Kelly Olson, a 0:02:54.400 --> 0:02:58.440 representative for the company Red Star Yeast. She said, when 0:02:58.560 --> 0:03:01.440 yeast has more time to work the dough, more flavor 0:03:01.560 --> 0:03:04.440 and a better texture is developed, and so there's some 0:03:04.480 --> 0:03:08.359 benefit to the more moderate active dry yeast. But then 0:03:08.400 --> 0:03:11.080 there are other products where instant yeast is very favorable 0:03:11.080 --> 0:03:15.880 as well. Instant east is more shelf stable than active 0:03:15.919 --> 0:03:19.680 yeast and provides more consistent results over time, which is 0:03:19.720 --> 0:03:22.000 great when you're baking in bulk or when you're looking 0:03:22.040 --> 0:03:26.280 for a more mildly flavored baked good. But you don't 0:03:26.360 --> 0:03:29.360 technically have to buy yeast. You can make your own. 0:03:30.840 --> 0:03:33.240 When people made bread in ancient times right up through 0:03:33.280 --> 0:03:35.800 the mid eighteen hundreds, they may not have known what 0:03:35.840 --> 0:03:38.360 they were doing, but they were making their own yeast. 0:03:39.280 --> 0:03:42.640 The same goes for you making a sour dough starter today, 0:03:42.840 --> 0:03:46.240 you simply mix equal parts filtered water and flour and weight. 0:03:46.880 --> 0:03:50.160 If conditions are right, naturally occurring yeasts that live in 0:03:50.200 --> 0:03:52.440 the air around us, we'll get to work and grow 0:03:52.480 --> 0:03:54.840 a colony that you can then use to make bread. 0:03:56.200 --> 0:03:58.880 Often throughout history, bread makers would get a little help 0:03:58.920 --> 0:04:02.240 from beer brewers. Sometimes these workers were one and the same. 0:04:03.280 --> 0:04:07.520 Baker's used balm the frothy east colony left over from 0:04:07.560 --> 0:04:11.800 brewing beer as a starter to raise their breads. Brewers 0:04:11.840 --> 0:04:14.560 at the time we're capturing wild yeasts as well by 0:04:14.640 --> 0:04:19.640 letting their beers ferment in open containers. But these wild 0:04:19.720 --> 0:04:22.760 yeasts are different from the packets of Baker's east available 0:04:22.760 --> 0:04:26.840 in stores. Olsen said. A commercial yeast is made from 0:04:26.880 --> 0:04:30.599 a pure strain of Saccaro Mices seravisier. When you try 0:04:30.600 --> 0:04:33.440 to make your own yeast, you're actually getting wild yeast 0:04:33.520 --> 0:04:38.280 that's not necessarily from sacaramceas servisier. You're not getting pure yeast, 0:04:38.480 --> 0:04:41.440 and you're not necessarily getting something that's consistent or that 0:04:41.480 --> 0:04:47.560 will perform the same as commercial yeast. That unpredictability, both 0:04:47.600 --> 0:04:50.719 with wild yeast and even with store bought yeast is 0:04:50.760 --> 0:04:54.920 one reason why yeast can intimidate bakers, but Olson, who 0:04:54.960 --> 0:04:58.839 feels numerous calls for Red Stars East customers, says Baker's 0:04:58.880 --> 0:05:02.159 East isn't a scary as it seems. She explained that 0:05:02.200 --> 0:05:04.280 it really comes down to watch in your dough while 0:05:04.279 --> 0:05:09.120 it rises, versus sticking solely to your recipes timetables. She said, 0:05:09.600 --> 0:05:11.760 I always encourage people to go by the look and 0:05:11.839 --> 0:05:14.640 feel of the dough. I use the recipe as a guide, 0:05:14.680 --> 0:05:17.119 but realize that things can vary from batch to batch, 0:05:17.279 --> 0:05:18.880 and so it's best to go by what the dough 0:05:18.960 --> 0:05:24.279 is doing. And yes, brewers and winemakers also use s 0:05:24.279 --> 0:05:29.039 Seravisier and other yeasts to create alcoholic beverages. In beer, 0:05:29.360 --> 0:05:32.479 yeast eats the sugars in malted barley to create alcohol, 0:05:32.600 --> 0:05:37.120 carbon dioxide bubbles and flavors. S. Sarahvisier is the go 0:05:37.240 --> 0:05:41.960 to for ale style beers, while another species, Sacchara Mices pastorianis, 0:05:42.040 --> 0:05:47.160 is typically used in laggers, and recently brewers began experimenting 0:05:47.200 --> 0:05:51.800 with wild yeasts again. In wine, yeast is already present 0:05:51.880 --> 0:05:54.960 on grape skins, but most winemakers also add a pure 0:05:54.960 --> 0:05:59.360 culture like s seravisier to ensure that their fermentation occurs reliably. 0:06:00.839 --> 0:06:04.040 The yeast is very particular and easy to kill. In 0:06:04.120 --> 0:06:06.960 temperatures of a hundred and twenty degrees fahrenheit or forty 0:06:06.960 --> 0:06:09.640 eight point eight celsius or higher will start killing it, 0:06:10.279 --> 0:06:13.280 but the cultures can go dormant and then be rejuvenated 0:06:13.320 --> 0:06:16.560 down the road, even if that road covers five thousand years. 0:06:17.520 --> 0:06:21.800 One egyptologist uncovered yeast microbes in ceramics from over five 0:06:21.800 --> 0:06:25.240 thousand years ago. He and his team extracted the yeast 0:06:25.520 --> 0:06:29.160 then baked bread with it, resulting in a successful sweet 0:06:29.200 --> 0:06:37.040 sour dough. Today's episode is based on the article yeast 0:06:37.120 --> 0:06:39.400 is the Magic microbe that makes Bread Rise on how 0:06:39.440 --> 0:06:42.880 stuff works dot com, written by Stephanie Vermillion. Brain Stuff 0:06:42.920 --> 0:06:45.119 is production of iHeart Radio in partnership with how stuff 0:06:45.120 --> 0:06:48.000 works dot Com and is produced by Tyler Klang. Four 0:06:48.040 --> 0:06:50.960 more podcasts my heart Radio, visit the iHeart Radio app, 0:06:51.120 --> 0:06:53.880 Apple Podcasts, or wherever you listen to your favorite shows.