food fermentation experiments

Food Fermentation: The Science of Cooking with Microbes

Explore the roles that microbes play in the production, preservation, and enhancement of diverse foods in a variety of culinary traditions, and learn about the history of food fermentations.

• Introductory

Associated Schools

Harvard School of Engineering and Applied Sciences

What you'll learn.

Have a greater understanding and appreciation of fermented foods and their history, culture and science

Have a deeper knowledge of beneficial microbes to preserve food and harmful microbes that can contaminate food

Have examined the underlying chemistry and microbiology of different kinds of fermentation through hands-on experiments— and honed your skills in experimental design, data analysis, and interpretation

Learned the scientific principles and application of instruments used for chemical and microbial characterization

Explored the chemistry of flavor molecules including the physiology of flavor and the microbial reactions that produce flavor molecules and other metabolites

Course description

What’s living in your food? Many of the foods that we consume daily owe their distinct characteristics and flavors to microbes, specifically through a biochemical process of fermentation (using bacteria, fungi, and other microorganisms to produce diverse foods). Gourmands and everyday consumers can quickly name some of the most popular fermented foods we consume—beer, yogurt, pickles—but, what about that coffee you drank this morning, or the chocolate bar you are saving for later?

Through hands-on, at-home exercises, you will experiment with your food to grow your own microbial environments to make mead, sourdough, tempeh, and more—and discover the important role science plays in food fermentation. In Food Fermentation: The Science of Cooking with Microbes, you will explore the history of food and beverage fermentations and how it changes and enhances flavors, aromas, and tastes. You will engage with your peers in kitchen science, discussing how and why fermentation does or does not happen and what conditions you should consider to create the right growth opportunities.

From chemistry to microbiology to your dinner plate, this course will analyze the role of microbes in production, preservation, and enhancement of diverse foods across a variety of culinary traditions.

Ignore the old adage. Are you ready to play with your food?

Instructors

Pia Sörensen

Roberto Kolter

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Biology Experiments On The Fermentation Of Yeast

Yeast is a fungal microorganism that man has usedsince before he had a written word. Even to this day, it remains a common component of modern beer and bread manufacture. Because it is a simple organism capable of rapid reproduction and even faster metabolism, yeast is an ideal candidate for simple biology science experiments that involve the study of fermentation.

What is Fermentation?

Fermentation is the biological process by which yeast consumes simple sugars and releases alcohol and carbon dioxide. For the most part, fermentation requires a mostly aquatic environment to occur. Different yeasts respond differently to changes in environment, making some better for baking and others for brewing. Bakers use fermentation to add CO2 bubbles to bread dough. During baking, these bubbles make the bread light and fluffy while the alcohol boils away. Brewers take care to preserve the alcohol of fermentation and use the CO2 to help build a frothy head for their potent beverages.

Indirect Life Test Experiments

The first experiment that should come to mind when examining yeast is determining whether or not yeast is a living organism. While it would be easy to rely on foreknowledge about the nature of yeast, more is learned by application of scientific method. If yeast is alive, it should consume food, respire and reproduce. Indirect tests look for clues that these processes are taking place. For such experiments, you should measure the amount of CO2 released by yeast that are digesting sugar water in test tubes with balloons attached. Use Benedict's solution to test for the presence of sugar in the final product.

Salinity Experiments

Fermentation is a delicate process that relies on ideal conditions to occur. Experiments that study how it responds to salinity are of particular interest to science and industry alike. Your project can either take a single type of yeast and vary the amount of salt in the solution to see if there is an ideal salinity, or alternately, use various yeasts to see how they respond to the same level of salt. In the latter experiment, make sure to use yeasts from many industries, since most baker's yeasts fare poorly in saline conditions.

Sugar Experiments

While it's clear that yeast requires sugar for fermentation, there are many different sugars that yeast could use for fuel. You can perform a number of experiments to determine which ones promote the highest level of yeast growth. In one, you can add yeast to various beverages, such as fruit juices and non-carbonated sports drinks to see which environment produces the most CO2. Another can use various sweeteners such as granulated sugars, syrups and nectars (such as agave) placed in weak solutions. You can measure CO2 production with balloons placed over the reacting test tubes, or simply observe the bubbles produced and make a relative comparison.

• The Science of Cooking: Yeast Air Balloons

Cite This Article

Klaus, Andy. "Biology Experiments On The Fermentation Of Yeast" sciencing.com , https://www.sciencing.com/biology-experiments-fermentation-yeast-12027557/. 9 March 2018.

Klaus, Andy. (2018, March 9). Biology Experiments On The Fermentation Of Yeast. sciencing.com . Retrieved from https://www.sciencing.com/biology-experiments-fermentation-yeast-12027557/

Klaus, Andy. Biology Experiments On The Fermentation Of Yeast last modified August 30, 2022. https://www.sciencing.com/biology-experiments-fermentation-yeast-12027557/

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Microbiology Made Fun and Simple

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A Beginner’s Guide to Fermented Food (Fermentation Experts Share Their Secrets)

May 30, 2019 //  by  Justine Dees

Can you believe that microorganisms can enhance our foods? It blows my mind a little that microbes can transform cucumbers into pickles or cabbage into sauerkraut. It utterly amazes me. Because of this incredible microbial trick, I have the pleasure of making my own fermented foods at home regularly. But I wasn’t always this enthusiastic about home fermentation. The idea of fermenting food at home used to make me a little nervous. As a microbiologist who studied pathogens for my PhD, I couldn’t help but think about what could go wrong.

At the same time, though, the idea of growing microbes at home appealed to me because I made a living growing microbes for 10 years. And people have been fermenting food for thousands of years without trouble. On top of that, my friends were brewing their own beverages and fermenting vegetables, and I, a self-proclaimed microbe expert, felt a pang of “Fermented Foods FOMO.” This realization sparked a journey of exploration fueled by a desire to understand the magic behind these delicious and gut-healthy foods.

This series is your guide to the wonderful world of fermented foods. We’ll explore what fermentation is, why it’s good for you, and how to overcome any apprehension you might have about getting started. Along the way, we’ll hear from experts and enthusiasts who are passionate about bringing the joy of fermentation into your kitchen.

So, whether you’re a complete fermentation newbie or a curious fermenter-in-training, join me as we delve into the bubbly, tangy, and fascinating world of fermented foods!

Fermented Foods FOMO

This post contains affiliate links — see my disclosure policy .

What pushed me to try it out was when I discovered some of my non-scientist friends were making their own pickles,  kombucha , sauerkraut , kefir , and beer. And I felt a little left out like I was behind somehow. I thought to myself, I am a microbiologist, so isn’t it strange that I know so little about this microbiology topic that brings so many people joy?

The little that I had learned about fermented foods in school was not enough for me to feel comfortable trying it out on my own. I knew I needed to do some reading. So, I picked up the book  The Art of Fermentation by Sandor Katz , and that was all I needed to start imagining the possibilities of making my own pickles, sauerkraut, and kombucha. Soon it became obvious to me that I needed to continue learning, but from some experts.

My First Fermentation Experiment

Meanwhile, I made my first attempt at home fermentation, but in an unconventional way. I tried making  kombucha , which is a type of fermented beverage made from sweet tea. It is especially popular right now in the US, and I wanted to understand why. So, I did an experiment using bottled kombucha from the store.

Usually, you would buy the microbes for the starter culture in the form of a scoby, which is a Symbiotic Culture Of Bacteria and Yeast. Instead, I felt clever and thought, I wonder if you can grow a scoby from a store-bought bottle of kombucha because they are supposed to contain live cultures. I did some googling and read that people have had luck with this method. Not every brand of kombucha actually contains live cultures, though, just to be clear. I found one that did, and then drank most of it (not straight out of the bottle, because I was worried about contaminating it — you know, being a microbiologist who studied pathogens). And when there were a few sediments left at the bottom —where most of the microbes in store-bought kombucha are — I added that to some sweet tea I made and let it sit in the cabinet for about a month. Eventually, I grew a pretty thick scoby. When I told this story to one of the people I interviewed—Arthur Serini, the co-owner of a company called The Crafty Pickle Co. —he said, “You grew a baby!”

When I posted this story on Instagram , one person responded that, “in the mid-90’s (my late teens/early 20’s) we had this slimy ‘pet’ that we fed sugar and tea, which I recently learned was kombucha.” She said they grew it just for fun and never drank it. I completely relate to that story, because it’s mostly fun knowing you have something brewing that you can check on every once in a while—like a super low-maintenance pet. (I guess that’s why I like succulents so much.)

It was thrilling and satisfying, especially because, with making fermented foods, it feels like I can bring the lab into my home and do experiments. Lab research and experimentation will always have a special place in my heart. Just because I’m not working in a microbiology lab anymore, doesn’t mean I will stop doing experiments.

Fermented Foods Series

To really do this topic justice, I decided to seek out the advice and wisdom of fermented foods experts and enthusiasts. So, I turned to Twitter, as you do when you have a science question, because you will instantly have experts ready to contribute. We truly live in an amazing time.

After I tweeted asking if anyone would like to be interviewed, I received many responses and recommendations. In the end, I interviewed seven different experts and enthusiasts, which expanded one blog post into five and, thus this series.

Here’s what the fermented foods series covers:

Part 1: Fermented foods series introduction.

Fermented Foods Part 2: The Joys and (Few) Risks of At-Home Fermentation : An introduction to fermented foods. What are they? What types of foods can we ferment? What do people love to ferment and why? Are there any safety risks?

Fermented Foods Part 3: Can fermented foods make us healthier? : Do fermented foods make us healthier?

Fermented Foods Part 4: Incorporating Food Fermentations Into Microbiology Courses : How fermented foods are being used as educational tools to teach microbiology students basic concepts as well as how to do research.

Fermented Foods Part 5a: A Fermented Foods Company Fighting Food Waste : Parts 5a and 5b are a couple of interesting takes on fermented foods. The story in Part 5a comes from the company I mentioned above, The Crafty Pickle Co., which is marketing their business from a different angle than most fermented foods companies — to fight against food waste.

Fermented Foods Part 5b: The Many Uses of Kombucha Scoby Cellulose : The second interesting fermented foods story is about a lab that uses kombucha scobys for alternative purposes in ways I could have never imagined.

Slowly but surely, especially after interviewing the wonderful experts and enthusiasts who actually knew what they were doing, my perspective changed. I was no longer nervous doing my own at-home ferments. Along the way, I also learned many interesting bits of information, so be sure to check out the entire series!

Additional Resources

• A Guide to Kombucha Fermentation and Microbiology
• The Microbiology And Making Of Milk Kefir
• How To Make Sauerkraut In A Jar
• Exploring Traditional Mexican Fermentation: Tepache
• Microbes play the music of fermentation on the fermentophone
• Podcast episode: The Microbiology of Fermented Foods: Dr. John Leech

Want to take your kids on a hands-on exploration of the microscopic world? Be sure to grab my ebook, ‘Joyful Microbiology Activities,’ which has 10 fun and simple microbiology activities you can do at home or in the classroom!

About the Founder

I’m Justine Dees, a PhD microbiologist, huge microbe enthusiast, and my passion is to share the wonders of the microbial world — especially how microbes impact our daily lives — through simple, easy-to-understand articles with as little jargon as possible.

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Top 50 Fun Food Science Experiments

Welcome to our carefully curated compilation of the top 50 food science experiments especially created for curious students and budding young scientists.

Are you ready to embark on a mouth-watering journey where science meets deliciousness? We’ve handpicked a collection of fascinating experiments that will tickle your taste buds and ignite your curiosity.

Edible Food Science Experiments

Edible food science experiments offer a delicious and engaging way for students and teachers to explore scientific principles in a hands-on and memorable manner.

By combining the fascinating world of food with the principles of chemistry, biology, and physics, these experiments provide a unique avenue for learning.

1. Magical Color Changing Unicorn Noodles

Get ready to enter a world of whimsy and enchantment with this captivating food science experiment: “Magical Color Changing Unicorn Noodles!”.

Learn more: Magical Color-Changing Unicorn Noodles

2. Glow in the Dark Jello

Prepare to be amazed and mesmerized by the enchanting world of “Glow in the Dark Jello!” Calling all curious minds and lovers of luminescence, this food science experiment will take you on a journey into the realm of bioluminescence and chemistry.

Learn more: Glow in the Dark Jello

3. DIY Soil Layers

Get ready to dig deep into the fascinating world of soil science with this captivating food science experiment: “DIY Soil Layers.”

This hands-on project will take you on a journey of exploration as you unravel the intricate layers that make up the foundation of our planet’s biodiversity.

4. Solar Oven

By building and using a solar oven, students will unlock the secrets of heat transfer, insulation, and sustainability. Witness the incredible transformation of sunlight into cooking power as you prepare delicious snacks with the sun’s energy.

Learn more: Solar Oven ]

5. Oreo Moon phase

This experiment not only offers a delightful treat for your taste buds but also introduces you to the fascinating study of astronomy and celestial phenomena.

6. Lava Toffee

Get ready to ignite your taste buds and witness a molten spectacle with this thrilling food science experiment: “Lava Toffee!”.

Calling all daring confectionery explorers and lovers of sweet surprises, this hands-on experience offers a fusion of culinary creativity and scientific discovery.

7. Fizzy Lemonade

This experiment is your ticket to becoming a beverage alchemist as you explore the science behind creating the ultimate fizzy lemonade.

8. DIY Home-made Ice Cream in a Bag

“Homemade DIY Ice Cream in a Bag!” Calling all students with a passion for dessert and a curiosity for science, this is an experiment you won’t want to miss.

9. Turn Milk into Cheese

“Turn Milk into Cheese!” If you’ve ever wondered how that creamy goodness makes its way from the farm to your plate, this is your chance to unlock the secrets of cheese making.

Learn more: Turn Milk into Cheese

10. Bread in a Bag

This experiment not only allows you to explore the science behind bread fermentation and yeast activation but also provides an opportunity to develop essential kitchen skills and creativity.

11. Edible Water Bottle

This experiment not only provides a practical solution to the global plastic pollution problem but also introduces you to the principles of food science and sustainable packaging.

12. Home-made Butter

Prepare to be amazed as you transform a simple ingredient into a creamy, spreadable delight right in the comfort of your own kitchen.

By participating in this experiment, students will not only discover the mesmerizing process of butter making, but also gain a deeper understanding of the science behind it.

13. Rock Candy Geodes

This experiment offers a delectable treat for your taste buds and introduces you to the fascinating world of minerals and crystal formation.

14. Make a Fizzy Sherbet

Get ready for a fizzy and flavorful explosion with this exciting food science experiment: “Fizzy Sherbet!” Calling all taste adventurers and fizz enthusiasts, this experiment is sure to tickle your taste buds and ignite your curiosity.

Learn more: Make a Fizzy Sherbet

15. Meringue Towers

This experiment not only allows you to explore the science behind meringue’s unique texture and stability but also provides an opportunity to develop your creativity and precision in the kitchen.

Learn more: Meringue Towers

16. Mug Cake

Students, this is your chance to dive into the fascinating world of culinary chemistry as you explore the principles of ingredient ratios, microwave heat transfer, and the science behind cake rising.

Learn more: Magic Mug Cake

17. Apple Experiment

This experiment not only stimulates your senses but also encourages critical thinking, data analysis, and creativity. So, grab your lab coats, sharpen your taste buds, and let the apple experiment take you on a journey of scientific discovery.

18. Grape Molecule

This hands-on experience not only allows you to engage with the principles of chemistry and molecular structure but also stimulates your creativity as you craft your own grape molecule masterpiece.

Learn more: Grape Molecule

19. Kitchen Chemistry

Get ready to mix, bake, and discover the magic of chemistry in the kitchen with this exciting The Kitchen Chemistry Cake Experiment!.

Calling all aspiring bakers and science enthusiasts, this hands-on experience offers a delectable blend of culinary art and scientific exploration.

Learn more: Cake Experiment

20. Sugar on Snow

This experiment not only offers a delicious sensory experience but also teaches you about the principles of heat transfer and phase changes.

21. Fibonacci Lemonade

As you pour and observe the layers of the Fibonacci Lemonade forming, you’ll gain a deeper appreciation for the harmonious relationship between science and art.

Learn more: Fibonacci Lemonade

22. Edible Glass

By combining simple ingredients and a touch of creativity, you’ll transform ordinary kitchen materials into a stunning and edible glass-like creation.

Learn more: Edible Glass

23. Edible Igneous Rocks Experiment

As you shape and mold the ingredients into rock-like structures, you’ll gain a deeper understanding of the volcanic processes that shape our planet. So, grab your materials, don your lab coat, and let’s embark on this delectable geological adventure.

Non-Edible Food Science Experiments

Prepare for a non-edible food science adventure that will ignite your curiosity and challenge your scientific prowess! These experiments will unlock the secrets of chemical reactions, physical properties, and the wonders of scientific exploration.

24. Magnetic Cereal

Prepare to be magnetized by the captivating world of “Magnetic Cereal!” This fascinating food science experiment will take you on a journey of discovery as you explore the hidden magnetic properties of your favorite breakfast cereal.

Learn more: Magnetic Cereal

25. Lemon and Battery

As you observe the lemon-powered circuit in action, you’ll gain a deeper understanding of the science behind electrical conductivity and the role of acids in generating power.

Learn more: Lemon and Battery

26. Milk Swirl Experiment

Prepare to be mesmerized by the enchanting “Milk Swirl Experiment.” This captivating food science exploration will take you on a journey through the mysterious world of surface tension and molecular movement.

Learn more: Milk Swirl Experiment

27. Bouncy Egg

Get ready for an egg-citing and egg-ceptional food science experiment: “Bouncy Egg!” Prepare to witness the incredible transformation of a fragile egg into a resilient and bouncy marvel.

Learn more: Bouncy Egg

28. Extracting Strawberry DNA

Through this hands-on exploration, you’ll develop a deeper understanding of the structure and function of DNA, as well as the importance of DNA in all living organisms.

29. Lemon Volcano Experiment

Calling all budding scientists and lovers of all things sour, this lemon volcano experiment is sure to leave you awestruck.

Learn more: Lemon Volcano Experiment

30. Electric Cornstarch

As you observe the cornstarch mixture respond to the electric current, you’ll gain a deeper understanding of the properties of matter and the interactions between electricity and materials.

31. Pop Rock Science

This hands-on experience not only offers a delightful sensory experience but also allows you to explore the principles of gas production, pressure, and the science of effervescence.

Learn more: Pop Rock Science

32. Frost in a Can

By using simple household materials, you’ll create your very own mini frost chamber that will transform warm air into a breathtaking display of frost.

33. Hopping Corn

Get ready to witness a popping and colorful spectacle with this captivating Hopping Corn experiment. This hands-on experience combines the excitement of popcorn popping with a twist of chemical reaction.

Learn more: Hopping Corn

34. Digestive System Experiment

Using a plastic bag filled with water, bread, and calamansi juice, you’ll witness firsthand how our bodies break down and extract nutrients from our food.

This experiment visually represents the digestive process and introduces you to our digestive system’s intricate workings.

Candy Science Experiments

Sweeten your curiosity and unleash your inner scientist with the thrilling world of Candy Science! Brace yourself for an explosion of flavors, colors, and mind-bending experiments that will leave you craving for more.

35. Skittles Rainbow

Prepare to unlock the secrets behind the mesmerizing phenomenon of color diffusion as you witness the magic of Skittles turning water into a vibrant rainbow.

Learn more: Skittles Science Fair Project

36. Home-made Fruit Gummies

By combining fresh fruit juices, gelatin, and a touch of sweetness, you’ll create your mouthwatering gummy treats bursting with fruity flavors.

This experiment not only allows you to customize your gummies with your favorite fruits but also allows you to understand the principles of gelatinization, texture formation, and the chemistry behind gummy candies.

Learn more: Home-made Fruit Gummies

37. Candy DNA Model

Get ready to unlock the sweet secrets of life with this fascinating Candy DNA Model food science experiment. This experiment offers a delicious and hands-on approach to understanding the fundamental structure of DNA.

Learn more: Candy DNA Model

38. Gummy Bear Science

This experiment is a sweet and chewy opportunity to uncover the fascinating world of polymer chemistry and osmosis.

By immersing these beloved gummy treats in different solutions, you’ll witness the mesmerizing process of gummy bear growth and shrinkage as they absorb or release water.

Learn more: Gummy Bear Science

39. Candy Camouflage

In this exciting activity, your favorite M&M candy colors represent different predators in a simulated ecosystem. Your task is to pick the right candy color that will allow you to survive and thrive.

40. How to Make Sedimentary Rocks

This experiment not only provides a creative outlet for your imagination but also introduces you to the fundamental principles of geology and rock formation.

41. Home-made Fluffy Marshmallow

Grab your mixing bowls, roll up your sleeves, and let’s dive into the world of homemade fluffy marshmallows. Join us on this marshmallow-filled adventure and let your taste buds soar to sugary heights

Learn more: Home-made Fluffy Marshmallows

42. Making Lollipops

This experiment not only allows you to explore the principles of sugar crystallization, temperature control, and the art of candy making but also encourages imagination and sensory exploration.

Learn more: Making Lollipops

43. Candy Chromatography

Get ready to unravel the colorful secrets of candy with this captivating Candy Chromatography experiment. This experiment will take you on a journey into the fascinating world of chromatography.

Learn more: Candy Chromatography

44. Dancing Worms

As you observe the worms twist, turn, and wiggle in response to their environment, you’ll gain a deeper understanding of how living organisms interact with their surroundings.

Learn more: Dancing Worms

45. Candy Atom Models

This hands-on experience offers a unique opportunity to explore the building blocks of matter in a fun and tasty way.

By using a variety of candies as representations of atoms, you’ll construct colorful and edible models that bring chemistry to life.

Learn more: Candy Atom Models

46. Kool Aid Rock Candy

Join us on this delicious and educational adventure, and let your taste buds and curiosity be delighted by the crystalline wonders of science. Get ready to taste the magic and witness the sweet transformation of sugar into dazzling rock candy crystals!

47. Starburst Rock Cycle

This hands-on experience offers a unique and mouthwatering way to explore the processes that shape our planet.

Learn more: Starburst Rock Cycle

48. Toothpick Bridge

By engaging in this activity, students can gain valuable insights into the principles of structural engineering, including load distribution, stability, and balance.

Learn more: Toothpick Bridge

49. Candy Potions

Get ready to mix magic and science with the captivating world of candy potions! This delightful food science experiment allows students to explore the wonders of chemical reactions while having a sweet and colorful adventure.

Learn more: Candy Potions

50. Dissolving Candy Canes

Get ready to explore the fascinating world of candy chemistry with the mesmerizing experiment of dissolving candy canes! This simple yet captivating food science experiment allows students to learn about the concepts of solubility and dissolution.

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The Science of Fermentation

How modern technologies make your favorite fermented food tastier.

Andy Tay, PhD is a freelance science writer based in Singapore. He can be reached at [email protected].

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Alcohol. Yogurt. Kimchi. Soy sauce. You name it: fermented foods are now a huge part of our diet. Attributing to their purported health benefits , they are also becoming more popular. Have you ever wondered what goes on during fermentation and the role of microorganisms in this process? This article provides a short historical walkthrough of fermentation, followed by a discussion on how modern biotechnologies can help make your favorite fermented food tastier.

What is fermentation?

Fermentation is the process of sugars being broken down by enzymes of microorganisms in the absence of oxygen. Microorganisms such as bacteria and fungi have unique sets of metabolic genes, allowing them to produce enzymes to break down distinct types of sugar metabolites. During fermentation, a variety of microorganisms are present in different proportions. The process is akin to a concert where different musicians (i.e. microorganisms) have their respective roles. Their cooperation produces beautiful music—our favorite fermented food. Therefore, when the types and numbers of microorganisms are changed, the taste of fermented food can also change dramatically. That is also why food companies take extreme care to safeguard their recipes and maintain their biobanks of microorganisms.

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Three basic forms of fermentation:.

• Lactic acid fermentation: During this anaerobic process, starches or sugars are broken down to produce lactic acid, among other waste products. Lactic acid bacteria not only protect foods from microbial spoilage, they protect the body from microbial disease. Lactic acid fermentation is commonly used in the production of foods like yogurt, pickles, and sauerkraut.
• Ethanol (or alcohol) fermentation: In this type of fermentation, pyruvate molecules in sugars are broken down by yeasts into alcohol and carbon dioxide molecules to produce wine and beer, as well as bread.
• Acetic acid fermentation: This oxidation process converts sugars from grains or fruit into sour tasting vinegar and condiments. Hence, the difference between apple cider and apple cider vinegar used for cooking.

History of fermentation science

Wine fermentation was documented as early as 7000 BC. In the old days, wine producers typically crushed fruits with their feet before leaving them to sit in containers. The transfer of microorganisms from the feet of wine producers to crushed fruits was hypothesized to cause fermentation. In the 17 th century, the hypothesis was validated when the invention of high-quality optical lens allowed visualization of single-celled microorganisms for the first time. Through a series of experiments, Louis Pasteur, a French microbiologist, showed that wine fermentation is caused by a type of fungi known as yeasts (and we do have a lot of them on our feet, gulp!)

In 1856, an accident at a sugar beetroot distillery led to a groundbreaking discovery that was pivotal to subsequent production of cheese and yogurt. Pasteur was tasked to investigate the issue and found that instead of alcohol, the “spoiled” beetroot mixture contained mostly lactic acid, which caused a sour taste. The sour beetroot mixture also contained many objects smaller than yeasts. These objects were later confirmed to be lactic acid bacteria. This serendipitous incident was instrumental to our modern day understanding that fungi and bacteria perform fermentation differently.

It was not until the early 1900s that Nobel Laureate Eduard Buechner discovered that fermentation can occur with cell-free yeast extracts consisting only of enzymes, contrary to what Pasteur proposed. Since then, we have produced a variety of fermented foods including the popular Kombucha. Although our ability to control fermentation is reasonably understood, there are still many ways industrial fermentation can be improved. For example, modern gene sequencing, genetic engineering, microfluidics, and electronic “nose” technologies can make our favorite fermented foods even tastier.

Popular fermented foods and drinks

1. Kimchi: Common in Korean cuisine, and made from fermented vegetables like cabbage and radish.

2. Kombucha: Fermented black or green tea drink known for its supposed health benefits.

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3. Miso: A Japanese seasoning or paste made from fermenting mashed soybeans and grains mixed with salt.

4. Mead: An alcoholic beverage made from fermenting honey with water, and can also include fruits, spices, grains, or hops.

5. Tempeh: The product of fermenting cooked soybeans, which binds the soybeans into a cake-like form.

DNA sequencing

During different stages of fermentation, the ratio of microbial populations can change with slight shifts in temperature and pH. Consider Kimchi, a traditional Korean food. Kimchi is usually produced by fermenting cabbage with lactic acid bacteria. However, different strains of lactic acid bacteria thrive at different pH ranges. For instance, Lee and colleagues found that during early fermentation (pH 4.27-5.64), Leuconostoc mesenteroides dominates, but as the environment becomes more acidic (pH 4.15), Lactobacillus sakei becomes the dominant lactic acid bacteria strain. Small environmental changes can drastically alter food consistency and quality, and there is a need to monitor microbial populations during fermentation.

DNA sequencing technologies are extremely useful to identify fluctuations in microbial populations. Each microorganism has its unique DNA make-up, just like how our fingerprints are unique to each of us. Researchers have made use of DNA sequencing tools to map out the genomes of many life forms, including that of microorganisms crucial for fermentation. Recent technological advances have also accelerated the speed of DNA sequencing and have rapidly driven down costs, making DNA sequencing more affordable for use in the food industry.

A few companies have tapped into DNA sequencing technologies to optimize their fermentation process. Beer Decoded sequenced yeast strains in 39 brands of beers from five countries to help discover new beer and promote production consistency. The data is also open-access and can be especially useful to small, independent microbreweries that are unable to conduct comprehensive studies. Through DNA sequencing, Kikkoman , a Japanese producer of soy sauce, also had a surprising finding. They found that besides the common fermentation helpers, lactic acid bacteria and yeast, two types of Koji mold were also crucial for fermentation. Recently, a group of Chinese researchers took DNA sequencing technology a step further by quantifying the proportion of various microorganisms at 11 different stages of shrimp paste fermentation . The team believes that their work can enhance quality control and food safety during shrimp paste production.

Genetic engineering

Genetic engineering (or modification) refers broadly to the cutting and pasting of the DNA genome to create cells with targeted traits. The efficiency of genetic engineering has improved with advanced gene editing techniques like CRISPR.

Genetic engineering has enabled the creation of microorganisms with more desirable traits than their wild-type cousins. For instance, Yu and co-workers generated a strain of Clostridium tyrobut yricum that produced higher yield of butanol, a type of sugar found in many fermented food, than its wild-type cousins. Microorganisms can also be genetically engineered to produce just one end-product with high purity. This makes them more advantageous than their wild-type counterparts, which usually produce a mixture of end-products. Companies typically prefer only one end-product to avoid having to perform any downstream separation, which can be expensive and technically challenging.

Droplet and microfluidic bioreactors

Traditional industrial-scale fermentation is performed in large bioreactors with capacity of a few thousand liters. This process is expensive and incompatible with quick testing of the next fermentation recipes. Droplet bioreactors, on the other hand, facilitate rapid fermentation as it confines raw ingredients and microorganisms together in tiny droplets of a few micro-liters to speed up fermentation.

Nevertheless, a major drawback of droplet microfluidics is that its production rate is (excruciatingly) slow. For instance, with the microfluidic wine bioreactor that Attinger and team has created, it will take close to nine years to produce a bottle of wine. At the moment, droplet bioreactors are most useful for testing new fermentation recipes and conditions. Do not expect them to replace traditional brewers anytime soon.

Earlier, we discussed the utility of genetically-modified microorganisms and how they have contributed to make fermented food production cheaper and more efficient. However, it is becoming increasingly clear that genetically-modified microorganisms behave differently when they are grown in a laboratory flask or industrial brewers. One factor causing this divergent behavior is the difference in physical stress they encounter.

Recall the most recent time you went swimming. Do you remember experiencing lower pressure at the water surface and rising pressure when you go deeper into the pool? This also happens to microorganisms swimming in large brewer. Microorganisms at the bottom experience much greater hydrostatic pressure. When this happens, they can burst and die. Others could undergo genetic or metabolic changes, thus sabotaging previous genetic engineering efforts. This is a huge problem for the food industry.

Researchers have tried to address this problem by building microfluidic bioreactors that can handle volumes up to a few liters. These microfluidic bioreactors function just like an industrial brewer but as a scaled-down version. Microorganisms can be grown in these scaled-down bioreactors and subject to different sensor-controlled pressures, stirring rates, temperatures, and pH. Next, by collecting data on the growth of microorganisms and product yield under these conditions, researchers can use this information to optimize fermentation in a scaled-up brewer. This can help realize industrial-scale production of new fermentation recipes.

Smell science in fermented foods

Our sense of smell and taste are intricately connected. Unfortunately, because of this, some people avoid tasty fermented food because of its smell. What if there is a way to remove the pungent smell while maintaining the tastiness of fermented food? This motivated Yan et al. to design an electronic “nose” for detecting volatile compounds from shrimp paste. Electronic nose is basically an array of electronic sensors that create unique electrical signatures when different compounds bind to them. These signatures are then fed and matched to a database of tested compounds. Using their technology, Yan and colleagues attributed the pungent smell of shrimp paste to propanoic acid. Similarly, Harper and co-workers also found using electronic nose that the aroma of cheese can be completely attributed to just five types of fatty acids. Interestingly, propanoic acid is also on the list. These research shows that electronic nose has the potential to help remove or enhance pungent/aromatic smell from fermented food.

Our future with fermented food science

Fermented food is everywhere. The yogurt in the breakfast. The soy sauce condiment accompanying our sushi lunch. And not to forget, our glass of wine during dinner. The demand for fermented food is getting stronger and so is the size of its market. In 2016, PepsiCo introduced its Tropicana Essentials Probiotics beverages. Peet’s Coffee also recently acquired a majority stake in Revive Kombucha . Modern molecular biology technologies can be exploited to generate microorganisms with desirable traits and monitor microbial populations during fermentation. Microfluidic techniques can also speed up testing of recipes for the next killer fermented product while electronic nose can ‘refine’ the smell of fermented food. I hope that the next time you consume your favorite fermented food, you will remember what happens during this amazing process and appreciate the technological innovations that were pivotal to the discovery of fermentation and very likely, its future trajectory.

About the Author

Andy tay, phd, related topics.

• Fermenters / Bioreactors ,
• Food and Beverage ,
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• 5 Fermentation Techniques You Can Do at Home by Chefs David Toutain and Joris Rousseau at Feuille

Discover Feuille’s fermentation techniques and sustainability philosophy and learn how to culture your own flavours at home.

Sustainability Paris Hong Kong sustainable Green Star

“I sold Joris my SCOBY from Paris,” jokes David Toutain, executive chef of his eponymous restaurant in Paris (Two MICHELIN Stars and MICHELIN Green Star, MICHELIN Guide France 2024). “Just kidding — SCOBY is always shared because it grows and thrives when passed around, making fermentation a zero-waste process.” Chef Joris Rousseau at one-MICHELIN-Starred and Green-Starred Feuille laughs in response, “That SCOBY is the symbolic bond between Paris and Hong Kong, linking both of our kitchens together.”

This playful exchange highlights more than just their shared love of fermentation. For both chefs, it represents a philosophy that connects the earth, the community, and the ingredients. “Fermentation is about preserving the memories of the land, the people, and the stories in every ingredient,” says Toutain. “It’s my way to slow down, savour the seasons, and reduce waste.” When he first opened Feuille in Hong Kong, he made sure his team embraced the same commitment to sustainability.

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An Ancient Technique That Continues to Shine Today

Fermentation, an ancient practice rooted in both Asia and Europe, continues to be as relevant today as ever. “When we ferment, we’re giving back, reducing our impact, and creating flavours that surprise and delight,” Rousseau adds. “It’s a way to connect with the world around me that’s both creative and sustainable.”

At Feuille , fermentation plays a key role in unlocking new flavours and textures. Take their Juniper-Oyster-Shallot dish, where fermented bananas add a surprising layer of acidity similar to umami, enhancing the banana’s natural sweetness. “By preserving bananas in salt over three weeks, fermentation transforms the flavour and texture, creating a unique mouthfeel with pronounced tannins that blend seamlessly with the oyster’s brininess,” explains Rousseau.

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But fermentation isn’t reserved for MICHELIN-Starred restaurant chefs — it’s something anyone can try at home. “When you ferment at home, you capture the true essence of produce, enriching its flavours with the unique depth that only time and a little microbial magic can bring,” says Toutain. “Beyond reducing food waste by extending ingredient life, it’s a way to savour the seasons all year and connect more deeply with the food on your plate.”

Ready to get things bubbling? Here are five essential fermentation techniques to kickstart your home experiments.

1. Lacto-Fermentation

Pairs well with : Grilled meats, creamy cheeses, and a cold beer or kombucha.

2. SCOBY (Symbiotic Culture of Bacteria and Yeast)

Method : Find a SCOBY online or from a friend. Brew a strong tea (black or green), and add 180g of sugar for every litre of tea. Once cooled, add the SCOBY and its liquid culture. Cover the jar with a cloth, then let it ferment for 10-15 days at room temperature. The SCOBY transforms the sugar into tangy, effervescent goodness. For aromatisation, like Feuille’s Chia Seed-Lemon Tree Kombucha, infuse your brew with fresh lemon tree leaves (or other herbs) from local farms to elevate the taste. Extend the fermentation for a few more days for a more sparkling kombucha but watch out for the pressure! (Right image: Jars of fermenting vegetables and fruits at Feuille .)

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Pairs well with : Fresh salads and light seafood if it’s a light, citrus-infused kombucha, or spicy dishes and rich meats if it’s a bold, fruit-infused kombucha; but best as a palate-cleansing drink on its own.

3. Kefir Culturing

Pairs well with : Fresh fruit salads, oatmeal, grilled fish, or light meals, and makes a great companion to herbal teas.

4. Soda Fermentation

Pairs well with : Light seafood dishes, fruit-based desserts, or as a refreshing drink on its own.

5. Fermented Hot Sauces

Method : Blend fresh chilli peppers (like jalapeños or habaneros) with salt and water. Place the mixture in a jar, and let it ferment for several weeks at room temperature, stirring daily. Once fermented, blend the peppers into a smooth sauce. The fermentation process enhances the depth and complexity of the hot sauce.

Pairs well with : Tacos, grilled meats, pizza, and can add a spicy kick to cocktails like Bloody Marys, and particularly IPAs. (Left image: Fermented lychee seed soda made from byproducts of the seasonal dish, Lychee-Bhutan Pepper-Marigold )

These five fermentation techniques are just the beginning—it’s an invitation from Toutain and Rousseau to reconnect with the earth’s bounty. At Feuille , fermentation goes beyond flavour; it’s about camaraderie, sustainability, and honouring what’s local and meaningful.

As Rousseau puts it, “My goal is to share my passion for fermentation with those who are interested. I’ve learned that Hong Kong once thrived with farms, and I hope to witness a resurgence of local agriculture, reclaiming the landscape.” By embracing fermentation, we’re not only reducing waste but fostering a more sustainable, flavourful future together.

Hero image by Hei Kiu Au, Chef Toutain and chef Rousseau demonstrating fermentation techniques at an exclusive workshop at F euille , Hong Kong.

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Hei Kiu is a Hong Kong-born food writer, photographer, and budding historian who loves to uncover extraordinary tales within your ordinary bowl of noodles. With a blend of Chinese-Portuguese roots, her work on Asian culinary heritage has been featured in a number of lifestyle publications, Oxford, and Yale-NUS.

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