Intro music
Fatu: “Hello everyone and welcome back to the show, We Love Science. My name is Fatu”
Shekerah: “And I am Shekerah, and today we have a special episode where we delve into our favorite of all topics: food science!
Fatu: Yes ma'am! There is so much science in food and it is all so fascinating and really drives our curiosity. Plus, it’s also delicious! So today we are gonna talk about YEAST – my favorite little food microbe.
Before we get started tho, how are you doing Shekerah?
Shekerah: (reply.) How are you Fatu?
Fatu: What are some of your favorite foods made with yeast? And least favorite?
Ok, let’s jump into our yeast talk!
Shekerah: What are yeast?
Fatu:
- Yeast is a single celled microscopic organism; a packet of yeast (like what you buy in the store for baking) contains billions of cells.
- This means 1 granule does not equal 1 yeast but 1,000s and 1,000s
- Yeast is used in cooking for its ability to digest different kinds of sugar (sucrose, fructose, glucose, maltose [maltose is in flour starch]) and produce carbon dioxide (gas) and ethyl alcohol
- Called fermentation
- Used in breadmaking and beer making; also winemaking
- Types of yeast
- Baker’s yeast or brewer’s yeast (Saccharomyces cerevisiae)
- Nutritional yeast, inactive yeast for flavoring food
- Wine and distiller’s yeast
- Yeast have been around since forever, and were first viewed under the microscope by Louis Pasteur in the late 1860’s.
Shekerah: So since yeast have been around forever, where did they come from? Are they just out there?
Fatu: YES! So if you think about it like sourdough bread, that uses wild yeast. (Talk about sourdough starter and variations in starter depending on the environment.)
Shekerah: Why did humans domesticate yeast?
Fatu: Well, let’s think about it. Like with other animals and plants we domesticate, humans like to optimize. We want a cow that makes the most delicious milk, sheep with the softest wool, and dogs that can truly be our best friends. The same is true for yeast.
Shekerah: Oh ok. So domestic yeast comes from wild yeast (found literally everywhere!) but have the advantage of being optimized
Fatu: Exactly!
Shekerah: And the commercialized yeast that we use today have been optimized for characteristics that would help for how we use them in cooking:
- To ferment more quickly
- To more efficiently withstand processing conditions such as freezing and drying
- To more efficiently break down and metabolize the complex sugar maltose. Maltose is the primary sugar present in “beer starter,” before the beer is fermented
Fatu: That’s right; better yeast means better cooking and more yummy final products. I notice this especially with my yeast from sourdough compared to commercial yeast. I have to let my sourdough sit a good 4 - 5 hours to get dough to rise, but with commercial yeast, I can have fluffy dough in like 2 hours. It takes me literally all day to make a sourdough loaf and only a few hours to make a simple white bread with store bought yeast.
Shekerah: Wait a minute though. When I go to the store, I never know what kind of yeast to buy. There’s so many different types. If we have already domesticated yeast so that it has properties we want that make it better for cooking, what’s with the different types of yeast at the grocery store - instant, active, and fast acting?
Fatu: Instant, active, and fast acting yeast are all processed slightly differently to allow for optimized performance for different styles of baking.
- For example, active yeast need to be “activated” with sugar and warm water before use, and are not as stable as other kinds of yeast
- Instant yeast is ready to go from the jump, and is extremely stable
Now this information was new to me. I’m kind of a sloppy baker so I will just grab whatever yeast, but now that I know there is a difference, I think I should be a little more intentional, and maybe I will have better outcomes.
Pretty cool right. Since I’m a baker, I mostly focused on yeast for baking, but I think it would be cool to have a part 2 to this knowledge nugget and talk about yeast for beer and winemaking.
Shekerah: That could be fun! Thanks everyone for joining us for today’s food science chat! If there are any foods you want to learn more about, let us know. And remember sometimes the best experiments, start in the kitchen!
Both: Bye
Outro Music
