Specimen 01
Sourdough Starter
Wild yeast and lactic acid bacteria. Eats flour, makes bread rise.
$14.99
Kitchen Lab · Experiment No. 1
Start something alive.
Cultured brings every fermentation project into one beautifully simple place, from sourdough to kombucha. Follow the steps, watch the science happen, and write down what you see.
- Free to get started
- No credit card required
- iOS + Android
yeast!
lacto!
the band marks where it started
bubbles = CO₂ = it's alive
Step 1 · Follow
Guided from day one
Clear, beginner-friendly instructions for every stage, so a first-timer of any age knows exactly what to do next.
Step 2 · Measure
Track what matters
Time, temperature, pH, photos and notes. The same observations a scientist would write down, kept tidy for you.
Step 3 · Repeat
One reusable system
A single universal kit works across projects. Finish the kimchi, wash the jar, start the kombucha.
Lesson · What's happening in the jar
Fermentation is tiny living things having lunch.
Every project in Cultured comes with the why, explained simply enough for a kitchen table and accurately enough for a classroom.
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1. You add food
Flour, tea, milk or cabbage all carry sugars and starches. That's the menu.
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2. Microbes eat it
Yeast turns sugar into carbon dioxide, the bubbles that make dough rise and kombucha fizz. Lactic acid bacteria turn sugar into acid.
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3. The jar gets tangy
As acid builds up, the pH drops. That sour environment is where the flavor comes from, and it makes life hard for unwanted microbes.
Inside the jar
Same idea, different lunch. Pick a ferment.
- Eats
- Starch and sugar in flour
- Who's eating
- Wild yeast + lactic acid bacteria
- Makes
- CO₂ bubbles, lactic and acetic acid
- Ready in
- 4 to 12 hours after a feed
The research
Good for your gut. Maybe your mood, too.
In a 10-week Stanford study, adults who ate more fermented foods grew a more varied gut microbiome and showed fewer signs of inflammation. Scientists are now studying how the gut and the brain talk to each other.
Wastyk et al., Cell, 2021. Early science, explained honestly.
Read the research · 5 minThe app
A better memory for your kitchen.
Part recipe guide, part lab notebook. Run every batch like a small experiment and keep what you learn.
Try it as an experiment
- Question
- Does a warmer spot make starter rise faster?
- Hypothesis
- The jar by the window doubles first.
- Measure
- Height above the band, temperature, pH.
- Record
- A photo and a note every hour.
- Conclude
- Compare both jars. Were you right?
Every ferment, at your level
Pick a project, then pick a level. The same batch, explained three ways.
Sourdough Starter
My Projects · sample data
Day 7
Time to feed. Stir in fresh flour and water, then slide the band to the top of the dough.
Check back in about 4 to 6 hours.
Time to feed. Stir in fresh flour and water, then slide the band to the top of the dough.
Why? Fresh flour is new food for the yeast. As they eat, they release CO₂, and the gas lifts the dough.
Kitchen is 24 °C, so expect it to double in about 4 to 6 hours.
Feed at 1 : 5 : 5 (starter : flour : water) and mark the level.
Temp24 °C
pH3.9
Hydration100%
Rise at 5 h+110%
Yeast activity peaks as the available sugars run low; acid keeps building after the rise slows.
- Step-by-step guides
- Timers and reminders
- Time, temperature and pH
- Batch photos
- Recipe discovery
- Reusable templates
Equipment list
The Universal Starter Kit
One jar, one lid, one weight: just what every culture needs. Nothing single-use, nothing doubled up.
- 1 wide-mouth jar
- 1 fermentation lid
- 1 glass weight
- Temperature strips
- Tamper + spatula
- Date bands + guide card
$39
Specimens
Meet the cultures.
Add a living culture to your kit. Each one is a different community of microbes with its own favorite food.
Specimen 02
Kombucha SCOBY
A Symbiotic Culture Of Bacteria and Yeast. Eats sweet tea, makes fizz.
$17.99
Specimen 03
Milk Kefir Grains
Not really grains: little clusters of bacteria and yeast. Eat milk sugar.
$16.99
Specimen 04
Kimchi Starter Pack
Cabbage, salt and lactic acid bacteria. Crunchy, sour, a little spicy.
$9.99
Four more to try
easy ones to learn on!Yogurt
Two bacteria turn warm milk thick and tangy in a few hours.
Needs a spoon of live yogurtSauerkraut
Cabbage and salt. The bacteria are already on the leaves.
No starter neededFermented pickles
Cucumbers in salty water, sour in a week or two.
No starter neededTempeh
A friendly mould knits soybeans into a cake in a day or two.
Needs tempeh starterGood questions.
Can one kit really do all of these?
Yes. The jar, lid and weight are the same equipment sourdough, kimchi, kombucha and kefir all need. You swap the culture, not the kit.
Can I use the app without the kit?
Yes. The app is free to start and works with whatever jars you already have.
Why a universal kit?
Most ferments need the same few tools. One kit you wash and reuse cuts waste and makes each new project cheaper to start.
Does it fit my mason jars?
Yes. The lid and weight are sized for standard wide-mouth jars, not a special container, so the mason jars you already own work.