sourdough — MikrobenKabinett

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MikrobenKabinett is what I call my fermentation cabinet — a bubbling, living archive.

Here I keep a growing collection of starter cultures that I’ve collected, nurtured, traded, or purchased over the years, along with several ongoing jarred fermentation experiments.

This page is a digital duplicate of the cabinet at home. It serves both as a record of each “member” in the Kabinett, and as a practical manual: If you’ve ever received a culture from me in real life, you’ll likely find its basic ratios and reference recipes here — to help you start your own fermentation journey!

Welcome to explore！
Xijing Xu

info@xijingxu.com
https://xijingxu.com
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Sourdough

Natural yeast fed simply with water and flour for bread baking

“Brigitte”

I got this starter from a friend, whose aunt originally raised it in East Germany in the early 1990s, when their family opened an organic store that also sold freshly baked sourdough bread. So I named this starter after his aunt.

Feeding ratio

1:5:5
starter : flour : water

I prefer to keep a small amount of sourdough to avoid too much discard. I usually keep 5 g from the previous batch and add 25 g of water and 25 g of flour.

For my standard bread, I typically need about 40 g of sourdough, which is more than enough.

Once the sourdough has doubled in size, you can start adding it to your dough. This usually takes about 6–10 hours, depending on the room temperature.

Feeding schedule

If you keep feeding the starter at room temperature, you can establish a rhythm where it needs to be fed twice a day.

If you store it in the fridge, you can check its condition once a week:

If it is not rising or only rises a little, let it rest further in the fridge. If you want to bake with it, bring it to room temperature until it doubles in size, then feed it again before baking.
If it becomes liquidy, feed it directly.
If there is black liquid forming on top, pour off the liquid and feed the starter again.

About the flour

It’s good to feed your starter with whole grain (Vollkorn) flour, so it gets the most nutritious part of the bran of the grain. It’s also a good idea to mix in a small amount of the type of flour you plan to bake with.

Brigitte is definitely an omnivore. I’ve tried wheat, rye, spelt, emmer, einkorn, quinoa, buckwheat, rice, corn... and she gets along with all of them!

My standard bread recipe

400g flour
You can decide the percentage of each flour type in your bread. I like to use 200g whole grain (often a mix of different whole grains), and 200g of German Typ 1050 or Italian Tipo 0.
300g water (75% hydration)
This is not a fixed number. Rye and quinoa absorb more water than other whole grain flours. Flours with higher protein allow for stronger gluten development, which also means they can handle more water.
If you want to make sourdough baking a long-term hobby, it's worth documenting your parameters each time — your intuition will develop over time!
40g sourdough starter (10% of the flour)

6g salt

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1. Mix all the ingredients.
Some people prefer to mix just the flour and water first (autolysis) to improve gluten development. Others prefer to mix the water, starter, and whole grain flour first, so the microbes can start enjoying their whole grain meal early on.
Every method has its reasoning — just do what feels right to you!

2. Knead the dough
Knead until you see the "windowpane effect" — a sign of good gluten structure.

3. Fold the dough every 30–60 minutes.
I personally never leave the dough at room temperature for more than 5 hours, as it can easily over-ferment.
Again, documenting your process each time — including the resting time between steps — really helps in the long run.

4. Shape the dough and place it in a basket. Bulk fermentation begins.
I prefer to keep bulk fermentation at room temperature for no more than 1 hour, then transfer the dough to the fridge overnight.
I once heard in a workshop that fermentation needs to last at least 8 hours for the nutrients in the flour to be fully transformed into a more digestible form. That’s why some people with FODMAP sensitivities can tolerate long-fermented sourdough, but not the 2-hour supermarket bread.

5. Score the bread and bake.
Be quick and bold with your scoring!
Adding steam at the beginning is essential. I find that tossing a few ice cubes into the Dutch oven is much easier than using a spray bottle.

This is a very simplified step-by-step recipe. I assume anyone who got this sourdough starter has at least some experience with bread baking.
If not, don’t worry — you’ll find tons of tutorials in any languages across the internet!

Reactivating a dehydrated starter

1

5g dehydrated sourdough
15g water

Let it sit, stir, let it sit again, stir again — over the course of about two hours, the dried starter will gradually dissolve into the water.

2

Add:
Previous starter mixture (from step 1)
15g flour
15g water

Stir vigorously to incorporate as much oxygen as possible into the mixture.

3

Once the starter begins to bubble and develops a pleasantly sour smell, it means the microbes have reawakened.

Continue repeating Step 2 every 12–24 hours.
When the starter can double in volume within a few hours after feeding, it’s fully reactivated — you can now switch to your regular feeding schedule and begin baking with it.

Some dehydrated sourdough starters