Online Fermentation Class
▶ Play the free introFerment kimchi, kombucha, rice koji, amazake and miso in an ordinary kitchen, on video with Sam Cooper, Sunday Times bestselling author and fermenter.
- 8 video lessons, 70 min
- 9 recipes
- English
- 4 lessons free
Rated 4.8 ★ by 7,552 App Store users and featured by
7 days free, full access. Every masterclass, 50,000+ recipes, 1,500+ chefs. Then €4.99/month on the annual plan or €9.99/month monthly; exact price by platform and region, shown before checkout. Cancel anytime.
The 8 video lessons
| Lesson | Access | |
|---|---|---|
 | Introduction What fermentation can do in an ordinary kitchen | FREE |
 | #1 Fermentation 101 Salt, temperature and hygiene: the controls | FREE |
 | #2 Lacto-fermented Tomatoes & Apricots Lacto-fermentation at a set salt percentage | FREE |
 | #3 Kimchi Kimchi without specialist equipment | FREE |
 | #4 Kombucha Kombucha in a vessel you can read by eye | FREE |
 | #5 Rice Koji - Part 1 Growing rice koji from scratch | PRO |
 | #6 Rice Koji - Part 2 Holding koji at the temperature the culture needs | PRO |
 | #7 Amazake Koji into amazake: sweet and quick | PRO |
 | #8 Miso Koji into miso: slow and salted, with safety checks | PRO |
Fermentation words you will use
- Lacto-fermentation
- Lactic acid bacteria already living on vegetables take over in an oxygen-poor salt brine and turn sugars into lactic acid. (Wikipedia (backup))
- Kimchi
- A traditional Korean side dish of salted and fermented vegetables. (Oregon State University Extension)
- Kombucha and SCOBY
- The "symbiotic culture of bacteria and yeasts" that turns sweet tea into kombucha. (UGA Extension)
- Koji
- A filamentous fungus, most commonly Aspergillus oryzae, used in Japanese cuisine to ferment food. (Wikipedia (backup))
- Amazake
- A traditional sweet, low- or non-alcoholic Japanese drink made from fermented rice. (Wikipedia (backup))
- Miso
- A thick paste made by fermenting soybeans with salt and koji. (Wikipedia (backup))
How long ferments take
From hours to years: one culture, rice koji, turns into both the quickest ferment in the class, amazake, and the slowest, miso.
- 10-14 hoursAmazakeRoot Simple
- 1-2 daysKimchi at room temperatureWikipedia (backup)
- 2-3 daysRice kojiWikipedia (backup)
- Up to 2 weeksKombuchaWikipedia (backup)
- 3-4 weeksSauerkrautUSDA / NCHFP (Univ. of Georgia)
- Days to yearsMisoWikipedia (backup)
Salt, temperature and safety in 8 rules
- A 3% brine is generally safe for shredded vegetables; whole or large pieces need a 5% brine. (University of Illinois Extension)
- A 3% brine is about 27 g salt per quart (approx. 0.95 l) of water. (University of Illinois Extension)
- Vegetable ferments work best at 68-72 F (20-22 C). (University of Illinois Extension)
- Kombucha (USDA-tested recipe): ferment at room temperature, 68-77 F (20-25 C). (USDA / NCHFP)
- Keep vegetables 1-2 inches (2.5-5 cm) under the brine; oxygen invites mold and yeast. (University of Illinois Extension)
- Kahm yeast vs mold: a flat white film that is not fuzzy or in round patches is kahm yeast and is safe. (University of Illinois Extension)
- Slimy texture or a spoiled or rotten smell means discard the ferment. (University of Illinois Extension)
- Kombucha starter liquid must test at pH 4.0 or lower before brewing (USDA-tested recipe). (USDA / NCHFP)
What you learn
This fermentation course teaches process before recipes. Lesson one sets the controls, salt, temperature and hygiene, and nothing that follows asks for specialist equipment. Rice koji is the spine of the second half: two lessons grow it, then it becomes amazake, sweet and quick, and miso, slow and salted.
- Grow rice koji from scratch across two lessons and hold it at temperature.
- Ferment kimchi and lacto-ferment tomatoes and apricots at a set salt percentage.
- Brew kombucha and make amazake, judging each by taste rather than by clock.
- Build a miso and run the safety checks that keep every batch fit to serve.
What you need
An ordinary kitchen: jars, a scale for the salt percentage, salt, and patience. The class page says nothing asks for specialist equipment.
7 days free, full access. Every masterclass, 50,000+ recipes, 1,500+ chefs. Then €4.99/month on the annual plan or €9.99/month monthly; exact price by platform and region, shown before checkout. Cancel anytime.
Take the fermentation class with you
Gronda was App of the Day in 120+ countries and holds 4.8 stars from 7,552 ratings on the US App Store. Watch every lesson in the app next to your jars, on iPhone or Android, and pick up in the browser where you stopped.
Download on the App Store Get it on Google Play
Free to download. The first lessons are free; PRO unlocks all 8 lessons with a 7-day free trial.
Your teacher: Sam Cooper
- Sunday Times #1 bestselling author (Gronda profile)
- British chef, fermenter, gardener; grew up on Shropshire farmland, lives in Wales
- Over a decade in restaurants built on organic Welsh produce
- Publishes as Chef Sam Black to an audience of over 500,000
- Books include The Fermentation Kitchen (DK)
"Fermentation rewards patience, give it time and the flavor builds itself."
Sam Cooper
Fermentation recipes by Sam Cooper
Gooseberry Amazakeby Sam Cooper, PRO recipe
Shio Kojiby Sam Cooper, PRO recipe
Mushroom Garumby Sam Cooper, PRO recipe
What members say about Gronda
App reviews shown on gronda.com, not reviews of this class.
"Gronda has excellent content from extremely talented chefs. I absolutely insist that all in house culinary personnel have Gronda on their phone."
Markus
"This app has the most amazing content. I'm a home cook, love preparing new and exciting recipes."
Lucas, App Store
Price and questions
What does it cost?
7 days free, full access. Every masterclass, 50,000+ recipes, 1,500+ chefs. Then €4.99/month on the annual plan or €9.99/month monthly; exact price by platform and region, shown before checkout. Cancel anytime.
Which lessons are free?
The introduction and lessons #1 to #4 are marked free on the class page; rice koji, amazake and miso are PRO.
Where can I watch?
In the Gronda app on iPhone and Android, or in the browser at gronda.com.
How do I cancel?
App Store or Google Play: in your phone's subscription settings. gronda.com: in your account settings. No fees, no calls.
7 days free, full access. Every masterclass, 50,000+ recipes, 1,500+ chefs. Then €4.99/month on the annual plan or €9.99/month monthly; exact price by platform and region, shown before checkout. Cancel anytime.