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.

Would you like me to format this translation as a readable, printable guide (e.g. PDF or Word) — with clear sections, headers, and a calm, instructional tone (like a sourdough manual)?

• 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.

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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. 

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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.

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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)

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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.

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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.

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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.  

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

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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.

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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.

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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.  

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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.  

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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.

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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

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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.

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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.