SOURDOUGH
DO IT YOURSELF

What is sourdough?

Sourdough is a mixture of flour and water in which naturally occurring bacteria and yeasts “pre-digest” components of the flour. During fermentation, carbohydrates are metabolised and gluten proteins are partially broken down.

This process produces a pleasant acidity that gives the bread flavour and helps extend its shelf life. Yeasts are also naturally present alongside lactic acid bacteria. They produce gases that make the dough rise and give the bread its light, airy texture.

Sourdough versus baker’s yeast?

Baker’s yeast is a cultivated yeast used primarily to produce carbon dioxide, giving bread and cakes volume and making the dough rise.

Sourdough, on the other hand, is a community of bacteria and yeasts working together to give bread flavour, improve digestibility and provide leavening.

In sourdough bread, fermentation plays a central role, while in breads made solely with baker’s yeast, the production of carbon dioxide by the yeast is primarily responsible for making the dough rise.

Sourdough breads are therefore often more digestible and generally keep fresh for longer.

The principle of sourdough: How does sourdough work?

Sourdough is a starter culture – a community of microorganisms. In German, it is often referred to as Anstellgut. A small amount of active sourdough starter is usually enough to initiate the fermentation needed to make a loaf of bread.

Bacteria and yeasts acidify and aerate the dough. During this process, starch is metabolised and gluten proteins are partially broken down. This works particularly well when the fermentation is carried out in several stages.

Rather than asking the microorganisms to do all the work at once, sourdough baking often involves preparing a preferment. This contains only part of the flour and water required for the final recipe, giving the microorganisms time to become active and multiply.

Once they have done their job, the preferment is combined with the remaining ingredients to make the final dough.

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CULTURES / FERMENTS & BOOKS

How to Care for Sourdough — Feeding Your Starter

Your sourdough is a living culture that feeds on grains.
It doesn’t matter much whether you use whole grain or white flour.
As a rule of thumb, if kept in the refrigerator, your starter should be “fed” at least every 7 days — meaning it gets new flour as food.

You’ll need:

50 g flour (rye for rye sourdough, wheat for wheat sourdough, etc.)
50 g water
5 g starter (about 10% of the flour amount)

Mix the ingredients well and place them in a sealable jar. Let the mixture stand at room temperature for about 2 hours so it can “wake up,” then put it in the refrigerator.
The starter will double in size, so make sure your jar is large enough — unless you were planning to give your fridge a deep clean anyway.
Repeat the process every 7 days.

Make your own starter or get one from someone else?

You can easily make your own starter — plenty of guides explain the process beautifully, and doing it yourself once helps you understand how it works.
However, getting a mature starter from someone else can be useful. Such starters already contain a richer community of bacteria and yeasts, making them more stable and flavorful.

By the way… people often treat their sourdoughs like pets, since they need regular feeding too. Some even give them names!
In one sense, this comparison fits: when your starter “moves in,” it might sulk a bit at first and needs time to adjust to its new home.
Treat it like a new family member, especially in the beginning — feed it daily so it gets used to its new food and environment.

Wheat starter, rye starter… do I really need one for each type of flour?

Yes and no.
If you already have a rye starter and want to experiment with wheat bread, you can use your existing starter.
But if you plan to bake baguettes or pure wheat breads regularly, it’s worth having a dedicated wheat starter. The same applies in reverse.

Alternatively, you can convert your starter.

Converting a sourdough starter

“Converting” means adapting your starter to a new type of flour.
Different flours have different compositions — for example, wheat has much more gluten than rye.
If you use a rye starter with pure wheat flour, it can’t break down the gluten structure as effectively.

To convert it, you slowly get it used to the new flour over several feeding cycles — gradually switching its “diet” to the new grain type.

What to do with leftover starter after feeding?

The short answer: discard it.
Never keep reusing the whole batch — by the fourth feeding, you’d end up with 10 kilos of starter!

Old starter is usually “spent,” which is why we refresh it — but you can still use it creatively:

Mix it with plenty of water and use it to water plants (a real enzyme cocktail!).
Mix it with flour (without water) and dry it — this creates a backup you can later revive with water if needed.

There are other ideas online (which I haven’t tested), but yes — you’ll sometimes throw away starter.
The good news: once you bake your own bread, you’ll almost never throw away bread again!
I grind any old, dried bread into crumbs and reuse them in new loaves.

What happens during sourdough fermentation

During fermentation, bacteria and yeasts do the work:

They break down the flour — starch (sugars) and gluten (proteins) are decomposed.
Acids form, giving the bread flavor and longer shelf life.
Gases form, which make the dough rise and become airy.

The result:
A flavorful, digestible, fluffy bread — completely free of additives.

Shelf life of sourdough breads

Unlike industrial bread, which turns hard quickly, sourdough bread stays fresh much longer.

The natural acidity helps retain moisture and reduces mold growth.

Wheat sourdough breads: 3–4 days
Rye sourdough breads: 7–10 days

Storage tips:

Wrap in linen cloths
Keep in bread boxes
Place the cut side down on a wooden surface (e.g., a cutting board)

Sourdough, gluten, and sensitivities

Many people experience bloating, heaviness, or discomfort after eating bread — often blaming gluten.
But the culprit isn’t always the protein itself; FODMAPs are often involved.

What are FODMAPs?
FODMAPs are short-chain sugars and sugar alcohols that are poorly absorbed in the small intestine and ferment in the colon, producing gas.

They’re a common cause of digestive discomfort.
During fermentation, bacteria and yeasts feed on them — doing part of the digestion for us.

Fermentation also reduces gluten content (though not completely).

The longer the fermentation, the more digestible?
In principle, yes — but longer fermentation also means a more sour taste and less fluffiness.

Many recipes recommend long, slow fermentation (so-called cold fermentation) in the refrigerator.
Lower temperatures allow the dough to acidify gently, producing a more balanced flavor.
This works especially well for high-gluten flours (wheat, Manitoba).

For low-gluten flours (like rye), however, you risk producing flat, dense loaves — once the microorganisms run out of food, they “fall asleep,” and so does your dough.

How to tell if your starter is still good

In all my years of baking, I’ve never managed to completely kill a starter — though anything’s possible!
The biggest enemy of sourdough isn’t neglect or hunger, but heat.
If your starter gets hotter than 40°C (104°F), it’s probably gone for good.

Moldy sourdough

Yes, sourdough can mold if contaminated by spores.
Always keep it sealed in the fridge to prevent contact with stray bacteria or mold spores.
If you see mold — throw it away and start fresh.

My starter has a black layer and smells alcoholic!

You’ve been caught neglecting your starter — you’ve starved it!
But you can make amends:
Pour off the alcoholic-smelling liquid, take a small amount (about 5 g) of the soft, bubbly starter underneath, and feed it again with 50 g flour and 50 g water.
Don’t use the whole thing.

A dense loaf! My bread didn’t rise — what went wrong?

In my early days, I baked plenty of dense, flat loaves even when following recipes perfectly.
Ultimately, success comes through practice.
I recommend taking a class with an experienced baker for one simple reason:
you need to see and feel what the right dough texture looks, smells, and feels like — no blog, video, or book can teach that.

Common mistakes:

Too hot: Yeast and starter can’t tolerate direct heat above 40°C (104°F).
Too cold: Dough will rise very slowly in the fridge — allow enough time.
Too wet: If the dough feels slimy or sticky, something’s off. You can add flour, but then you’ll need to adjust salt and starter amounts — or start over.
Too stiff: No matter what bread you’re making, the dough must have some elasticity before baking. If you have to press hard to make an indentation, something’s wrong.
Too impatient: The most common issue — and one only experience can fix.

I only bake bread occasionally — is it worth keeping a sourdough? Try yeast water!

Your sourdough only needs feeding once a week — less demanding than pets or even many houseplants.
But if you forget about it, or it develops a black film, your baking enthusiasm can quickly fade.

In that case, it’s easier to keep yeast water in the fridge.
The process is simple and effective:

Take a handful of raisins (unsulfured is best).
Put them in a 0.5 L plastic (PET) bottle, fill with water, close, and shake well.
Leave it in a warm place and shake once a day.
After a few days, the bottle will become firm with pressure — fermentation has begun!
Don’t open it yet. When the bottle is so tight you can’t press dents into it, move it to the fridge — your instant starter is ready.

When baking, simply use this yeast water instead of regular water in your preferment — it already contains natural yeast.

⚠️ Important: Never use a glass bottle!
Fermentation builds pressure that can cause glass bottles to explode — plastic (PET) is a safety measure.

Help! My starter smells like glue and has a watery gray layer!

You’ve neglected your ferment — but don’t worry!
With some care, you can rebuild your relationship.
Just follow the feeding instructions again and repeat daily until it’s bubbly and healthy again.

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50 g wheat flour 700 smooth / rye flour smooth or whole grain
50 g lukewarm water
5 g sourdough starter (10% of the amount of flour)

Mix the ingredients and let the mixture sit out in a sealable glass for 8-12 hours at room temperature. The dough will double in size, so use a large enough container.

After the dough has risen, put the jar in the refrigerator. Your sourdough now has enough food for 7 days. Repeat the procedure after 7 days.

Prepare sourdough yourself or get it from someone?

Sourdough is easy to make. The process is explained here . Doing it yourself does make sense as it gives a lot of insight into how the process works. Nonetheless your bread does profit from an "old" sourdough culture, that has been fed for year, due to its bacterial complexity that it acquired over time.

Wheat sourdough, rye sourdough ... do I really need a separate sourdough for each flour?

Yes and no!

Anyone who already has a rye sourdough and would like to take a "bake trip" to wheat bread wonderland can do so with his rye sourdough. However, if you intend to bake baguettes or pure wheat bread more often, it is worth buying a wheat sourdough. This does apply the other way round too, of course.

What do I do with the leftover sourdough after freshening up?

The quick answer is you dispose of it. In any case, don't make the mistake of processing all of that sourdough over and over again. At the latest with the 4th refreshment you would have 10kg of sourdough.

Your old sourdough is usually gnawed off, that's why it is freshened up.

Nevertheless, here are a few variants that make it possible to make something with your old sourdough:

- mix it with enough water and pour it over plants (a real enzyme cocktail)

- Mix old sourdough with flour (without adding water) and dry it (as an emergency nail, if something could be with your sourdough, the dry mixture can be brought back to life with a little water)

There are other suggestions on the Internet, but I haven't tried them myself. But if it helps, yes, they will throw away sourdough well, but if you bake your own bread you will probably never throw away bread again. I grind every crumb of stale bread into crumbs, which then find their way back into the bread.

I only bake bread every now and then. Is it worth keeping a sourdough for this? Yeast water!

Once a week your sourdough craves fresh food. It is therefore less demanding than domestic animals and many house plants. Still, it's easy to forget about it when you don't need it. And understandably, when you feel like baking bread and the thing in the refrigerator is covered with a black layer of streaks, the joy of baking is already extinguished again.

In these cases it is better to keep some yeast water in the refrigerator. The process is simple and effective.

Take a handful of raisins (unsulphurized is better) and put them in a 0.5 L PET bottle. Fill up with water, screw on, shake well and let stand in a warm place. Shake it once a day. After a few days, the bottle becomes really bulging. It is fermenting. Do not open! When you can't make dents in the bottle, put it in the refrigerator. Your instant items are ready.

When baking, you now use yeast water instead of water for the pre-dough. Anstellgut is already included in the water.

Warning: even if it is meant well, never use a glass bottle. The PET bottle, i.e. plastic, is a safety measure. Fermentation creates high pressure that can cause the bottle to explode. When a glass explodes, more than just a few raisins fly through the air.

Help! My sourdough smells like glue & is covered in a watery, grayish layer.

They neglected their ferment. But keep your head up - with a little attention you can rebuild a relationship with him / her. Just follow the refresher guide. Repeat the procedure every day until it produces nice bubbles again.

How do I know if my sourdough is still good?

In my many years of baking bread, I have not yet succeeded in completely destroying a sourdough. But of course it is possible. Sourdough's greatest enemy is not deprivation of love or diet, but heat. If you heat your sourdough above 40 degrees, it is very likely part of the history of your baking career.

Freshen up your sourdough, if it has doubled in volume after 12 hours, it is "in perfect shape". If not, try refreshing it again. If there is no increase in volume, call the sourdough funeral home. If so, continue to ventilate or feed in this case.

A tough one! My bread didn't rise. What I have done wrong?

In my early days I baked a lot of hard chunks of bread and with the best of my will I can't tell you what I would have done wrong, because I absolutely stuck to the recipe.

At the end of the day, it's a matter of repetition, and I recommend taking a course with an expert for one reason: you must have seen and felt the right consistency of the dough, smell, and feel. No blog, video or book can convey that to you.

Common mistakes, however, are:

Too hot - yeast and sourdough cannot tolerate direct heat above 40 degrees
Too cold - if you let your dough rise in the refrigerator, it will take longer and it will rise, but you have to factor this in
Too wet - if you have a slippery, mushy texture in your hands, something has gone wrong. Yes, you can then add enough flour to make bread consistency, but then you also have to adapt the amount of salt and sourdough ... or you can leave it and start over
Too hard - no matter what bread you have - it must have a certain elasticity before baking. If you have to dig your finger into it hard, something is wrong.
Too impatient - probably the biggest problem, but one that can only be solved with the necessary experience

What is the best way to store bread?

Good bread doesn't go moldy, it dries up. Unless you choke on it. I always put my bread with the cut on a wooden board. I never give it in plastic and I am not a fan of lunch boxes, as they soften the crust much faster than necessary.

I am gluten intolerant? What bread can i eat?

If you have been diagnosed with Celiac Disease, you know that anything gluten containing must be avoided. However, if you want to limit your gluten intake and still don't want to go without bread, then try very well leavened rye breads. Rye contains less gluten than wheat or spelled. If it is then acidified even more, i.e. the dough simply rises longer, even more of the gluten structure is broken down. The bread tastes more sour than usual, but contains less gluten.

FEEDING & CARING FOR YOUR SOURDOUGH STARTER

Your sourdough starter is a living culture that feeds on grain. Whether you use wholemeal or refined flour is not particularly important. As a general rule, a starter kept in the refrigerator should be “fed” at least every 7 days. Feeding simply means giving it fresh flour as food.

For one feeding, use:

50 g flour (rye for a rye sourdough starter, wheat for a wheat starter, etc.)
50 g water
5 g sourdough starter (10% of the flour weight)

Mix the ingredients and transfer the mixture to a sealable jar. Leave it at room temperature for about 2 hours to get the fermentation going, then place it in the refrigerator.

The starter will roughly double in volume, so make sure your container is large enough – unless you were planning to give your fridge a thorough clean anyway.

Repeat the process after 7 days.

Storing your sourdough starter

If you don’t bake every day, the refrigerator is the best place to keep your sourdough starter. The microorganisms remain active there, but everything happens much more slowly.

Feed your starter once a week.

Taking a break – storing sourdough for longer periods

Going on holiday, short on time, or simply don’t feel like baking? There are ways to store your sourdough starter without having to maintain it regularly, even in the refrigerator:

Freeze your sourdough starter
Dry your sourdough starter

When reactivating it, allow a few days and feed the starter regularly for 2–3 consecutive days before using it for baking again.

What should I do with leftover sourdough starter after feeding?

The quick answer: discard it.

Whatever you do, don’t make the mistake of keeping and feeding the entire starter every time. By your fourth feeding, you could easily end up with 10 kg of sourdough.

The old starter has generally exhausted much of its available food – which is precisely why we refresh it.

There are, however, a few things you can still do with your old starter:

Dilute it generously with water and use it to water plants.
Mix the old starter with flour, without adding additional water, and dry it. This makes a useful backup: if anything ever happens to your active starter, the dried mixture can be revived with water.

You’ll find plenty of other suggestions online, although I haven’t tried all of them myself.

And if it makes throwing away a little starter easier: yes, you will occasionally discard some sourdough starter. But if you bake your own bread, chances are you’ll never throw away bread again. I grind every last piece of stale bread into breadcrumbs – and eventually they find their way back into a new loaf.

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WHEAT DOUGH - LOAF

Equipment:

1 tall mug at least 0.5L
1 wide bowl / proofing basket

Ingredients generic

Wheat flour 700 smooth
Sourdough starter
salt
Germ, fresh

The night before:

Wheat sour

100 g wheat flour 700, smooth
100 g lukewarm water
10 g sourdough topping

Mix wheat flour, water and sourdough and

Let rise overnight in a tall mug at room temperature.

Autolysis dough

550 g wheat flour 700 smooth
350 g of water

Mix lump-free and close the bowl (foil, lid or tip: shower cap). Let stand overnight.

On the baking day :

Main dough

Wheat sourdough (after 12h from above)
Autolysis dough (after 12h from above)
30 g wheat flour 700 smooth
16 g salt
70 g of water
5 g fresh yeast

Knead all ingredients well for at least 6 minutes. Now the dough rests for 3 hours at room temperature in a lightly oiled bowl covered with foil. After the first 30 minutes, you should fold the dough, that is, grab under the dough in the bowl with wet hands and pull it towards you at chest level. Let the dough hang out a little and drop it back into the bowl. Turn the bowl slightly & repeat the procedure. Cover the bowl again.

After another 60 minutes, repeat the process of folding. After the 3h dough rest, your dough can be shaped. The folding made it more robust. Now shape it into a loaf.

When shaping, make sure not to knead or press the dough any more, but rather push it together. The volume should be retained.

Now the dough is placed in a floured bowl. The smooth surface looks up and is just as lightly floured. Cover the bowl with a cloth & let it rest for 1 hour.

Now preheat the oven to 240 degrees, top-bottom heat. A pizza stone will help make the bread crispy on the underside as well. Alternatively, you can also preheat a baking sheet. It is important that the pizza stone or baking sheet is preheated for at least 40 minutes. Also place a small stainless steel pot on the bottom of the oven.

The dough in the bowl has now rested for 1 hour at room temperature. Prepare a small glass of water / water syringe and place it next to the oven. This is how we create the steam that gives the bread its crispy crust.

Open the oven, pull out the pizza stone / baking tray and turn the bread upside down from the bowl.

Pour the glass of water / contents of the water syringe as quickly as possible into the small stainless steel pot at the bottom of your oven and close it quickly. The steam should stay in the oven as much as possible and not escape immediately.

The bread bakes for about 50 minutes. After 30 minutes, open the oven for 10 seconds so that the steam can escape. Reduce the temperature to 220.

Cast iron pot variant:

Wheat dough is softer than rye dough. As a result, they tend to run wide in the oven. A good method is to use a cast iron pot as a baking pan. This is also preheated for 40 minutes. The only difficulty with this method is to let the bread "flop" out of the proofing basket exactly into the pot. Put the lid on and put it in the oven. After about 30 minutes, remove the lid and finish baking.

After a total of 50 minutes, your bread should have risen, nicely crusted and sounded hollow on the underside (tapping test). If you have a roast thermometer at hand - the desired internal temperature is 95 degrees.

Even if it is tempting to cut the bread now, let your bread cool down, the residual heat in the bread bakes it to the end outside of the oven.