two 16 oz deli containers sit side by side. the one on the right has about half an inch of mature sourdough starter in it. the one on the left has about a quarter of an inch of newly fed sourdough starter in it and is labeled with masking tape that says "starter."

how to maintain a small sourdough starter

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This post is for anyone who wants to learn how to maintain a smaller amount of sourdough starter that can easily be grown into a larger amount for baking.

For my 6 beginner tips for feeding and discarding your sourdough starter, click here.

When it comes to feeding your sourdough starter, there’s no one way to do it right. There’s only the way that works for you. Of course, there are ways to do it wrong, but that’s not what this post is about. As long as you’re using filtered (non-chlorinated) water, occasionally cleaning the container you keep it in, storing it in the fridge, and preventing it from drying out, your starter — big or small — will be fine even if you go a month or two between feedings.

As I’ve written about before, for a long time I had the same, consistent sourdough feeding routine: 4 ounces of starter with 4 ounces of filtered water and 4 ounces of flour. I fed it every couple of weeks, and a few days in a row before I planned to bake with it. Always the same 4 oz:4 oz:4 oz ratio (a 1:1:1 ratio, for you math nerds out there).

The instructions I got with the starter said to feed it that way, so that’s what I did. I didn’t want to risk killing my second starter, so I didn’t deviate from the system. And it worked pretty well for a while!

But if you do the math, 4 ounces of starter + 4 ounces of water + 4 ounces of flour = a lot of starter! Few recipes, even discard recipes, call for anywhere near 12 ounces of starter. So when the pandemic hit and flour was harder to come by, I began looking for ways to scale back the amount of starter I was maintaining.

two 16 oz deli containers sit side by side. the one on the right has about half an inch of mature sourdough starter in it. the one on the left has about a quarter of an inch of newly fed sourdough starter in it and is labeled with masking tape that says "starter."
mature starter (left) and recently fed starter (right)

Like everyone else in the world, I learned a lot about sourdough in the early days of quarantine. I read the Tartine bread book, I read Flour Water Salt Yeast, and I read hundreds of posts in various sourdough baking groups on Facebook.

The single most important thing I learned was how to make sourdough using levain. This is the method used to make the standard country loaf from the Tartine bread book. I had baked sourdough with levain before using this recipe from The Kitchn (which is a modified version of a Tartine loaf), but I had just been following the steps. I didn’t fully understand what levain was.

Understanding levain changed everything.

understanding levain

Levain (or leavan) is basically exactly the same as sourdough starter, just younger. It’s a portion of your mature sourdough starter that you feed and use almost all of in your dough.

Fair warning: I’m going to massively simplify it here, just enough to explain what you need to know to maintain a smaller starter. To really understand levain you should read the Tartine bread book (or this helpful guide on The Kitchn), which goes into much greater detail about the science and temperatures and different types of bacteria and wild yeast and lactic acids in your starter and how they work.

So here’s the short version: When you bake sourdough with levain you take about 1 TBSP of your mature (fed within the last 24 hours) sourdough starter (25g) and feed it a proportionately larger amount of flour and water — like 100 or 200g of each. It becomes a young, very active, sweeter smelling, more mellow flavored version of your sourdough starter.

If you don’t bake with your levain when it’s at its peak (which will depend on the temperature of the flour, water, and starter and the ambient temperature) it matures back into, well, mature sourdough starter.

I usually build my levain the night before I plan to bake with it — which means it peaks around 8-12 hours after feeding. But I use cold starter from the fridge, cold water from the fridge, and my apartment is usually cool. If you use room temperature starter, room temperature water, and have a warm apartment, your levain might be ready in as little as two hours.

a 16 oz deli soup container filled about halfway with slightly bubbly sourdough starter
levain

When you bake with levain, you use almost all of it in your dough. Then you feed the remaining 1 TBSP or so of remaining levain with equal parts flour and water and it becomes your new mature starter.

It’s a much more sustainable sourdough process! And it totally opened my eyes to the unnecessary amount of flour I was using to maintain a massive 12 ounces of starter. Why feed it a full cup of flour at every feeding when I only needed 1 TBSP of mature starter to make levain for baking? Especially since I keep my starter in the fridge, and therefore need to feed it a few days in a row before baking with it.

The old way I fed my starter meant I’d often end up with an unwieldy amount of discard. And though I enjoy making sourdough discard scallion pancakes, understanding levain made it abundantly clear that my flour was better put to use feeding the levain when I wanted to bake than it was maintaining a large amount of unfed starter sitting in my fridge.

feeding your small sourdough starter

In the videos below I’m feeding my starter at a 1:2:2 ratio — 30g starter, 60g water, 60g flour. I feed my starter a 50/50 blend of AP and Whole Wheat flour.

1
Measure your sourdough starter into a clean bowl on a kitchen scale.
2
Add an equal or greater amount (by weight) of filtered water to the starter.
3
Stir to combine and break up the starter.
4
Add the same amount of flour (by weight) as you did water to maintain 100% hydration.
5
Mix to fully combine.
6
Cover and let feed at room temperature until bubbly and active.
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Feeding a small sourdough starter is exactly like feeding a larger starter. It’s just smaller quantities.

If I’m feeding my starter just because it’s been a while and I want to make sure it’s refreshed, I’ll weigh 1 tablespoon of starter (and discard or use the rest) and feed it using a 1:1:1 ratio. So if 1 TBSP starter = 25 grams, I’ll feed it 25 grams flour and 25 grams filtered water.

But that’s just to maintain a small starter. What if you need more to bake with?

scaling your starter up for baking

I keep my starter in my fridge because I don’t bake with it that often. Maybe once a month or so. When I know I want to bake with it, I take it out of the fridge and pour off any hooch (black-ish liquid) that’s collected on the top. Then, I measure out 1 tablespoon of starter by weight (25g), and feed it equal parts flour and water and let it sit at room temp for anywhere from two to 24 hours.

This first feeding is a small 1:1:1 feeding just to wake it up from its fridge slumber. I’ll discard most of it and feed it again before I bake with it, so I don’t want to feed it any more flour than I need to yet.

Depending on how active my starter gets after the first feeding, I might two or three more 1:1:1 feedings over the course of a day or two. Usually it’s active enough after the first feeding that I can scale it up at the second feeding.

a very small amount of sourdough starter floating on the surface of water in a tall pint glass
When your starter passes the “float test” it’s active enough for baking.

The last feeding before I bake with it is when I feed it like I’m building a levain. I use just 1 TBSP of my mature starter, but if 1 TBSP starter = ~25 grams, I’ll feed it 50 or even 100 grams (sometimes as much as 200 grams!) each of flour and water.

Remember, it’s all about ratios. So if you measure 1 TBSP and it’s 27g or 30g instead of 25g, that’s fine. And you can feed it with 108g flour and 108g water and it’ll work just fine, too.

What matters is that the flour and water are equal to each other by weight, and that the amount of each is equal to or greater than the amount of starter. I use whole round numbers like 25g, 50g, and 100g just to keep things simple!

deciding how much flour and water to use

Deciding how much flour and water to add to my 1 TBSP of starter when I scale it up for baking depends on how much starter my recipe calls for. For a recipe that calls for 200 grams of active starter, I’ll feed 1 TBSP of starter 110 grams flour and 110 grams water. That will grow into slightly more than 200 grams of levain.

Then, to bake, I’ll measure out the 200 grams I need for the recipe. This will leave about 1 TBSP of starter in my container, which I’ll feed with equal amounts of flour and water. This becomes my new small starter, which I let feed at room temp for a few hours before sticking it back in the fridge until I’m ready to use it again.

The best part? This method of feeding works whether your recipe calls for levain (like the Tartine’s country loaf does) or mature starter. If your recipe calls for mature starter, simply let the levain sit longer before you use it.

accounting for taste

A starter fed at a 1:1:1 ratio will have a more intense sour flavor than a starter fed at a 1:4:4 or 1:8:8 ratio. When the starter makes up a smaller portion of the fed starter, the flavor will be mellower overall. The greater the amount of new flour and new water are in proportion to the amount of starter, the more diluted the sour flavor will be.

If you want to maintain a small starter, but also want your fed starter to have an intensely sour flavor, do your first feeding as a small feeding, but then use ALL of your fed starter in your second feeding.

So your first feeding will be be 25g starter, 25g water, 25g flour (1:1:1). That will give you approximately 75g fed starter.

The next day, in preparation for baking, you’ll feed your whole 75g starter with 75g water and 75g flour (also 1:1:1). This will give you approximately 225g starter. If you use 200 grams of that starter in your dough, you’ll have 25 grams left which you can feed with 25g water and 25g flour. Boom. Your small starter is back.

small starter discard

What about the small starter discard? Because a smaller starter means smaller discard, I feel less guilty if I throw some out. But if I know I want to make something that calls for sourdough discard, I’ll save my small amount of discard in a container in the fridge and just keep adding more discard to it with each feeding.

I feed my starter a few times in a row before baking with it anyway, so the combined discard from 2 or 3 feedings is usually enough to bake with. It’s totally fine to store that discard in the fridge for several days or even a week or two before baking with it, too. Just remember, the longer it’s been since it was last fed the more sour and less active it will be.

two 16 oz deli containers sit side by side. the one on the left has about half an inch of mature sourdough starter in it. the one on the right has about an eighth of an inch of starter, which has just been fed and has yet to rise at all.
a small mature starter (left) and a newly fed small starter (right)

In the photo above, the 16 oz deli container on the left is my mature starter. I took 1 TBSP of starter from there, placed it in the container on the right (labeled: STARTER), and fed it equal parts flour and water. When it’s done feeding, it will be about the same size as the starter on the left. It will be my new starter.

The starter on the left is now my discard starter. I can either throw it out, or I can stash it in the fridge and add more discard to it when I feed the new starter (on the right) ahead of of baking with it.

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two 16 oz deli containers sit side by side. the one on the right has about half an inch of mature sourdough starter in it. the one on the left has about a quarter of an inch of newly fed sourdough starter in it and is labeled with masking tape that says "starter."

feeding a small sourdough starter

The Practical Kitchen
Don’t feed your sourdough starter cups and cups of flour when a few tablespoons will do.
0 from 0 votes
Prep Time 10 mins
Total Time 10 mins
Course Technique
Cuisine French
Servings 75 grams

Equipment

Ingredients
  

  • 25 grams mature sourdough starter (approx 1 TBSP)
  • 25-200 grams flour (equal to or greater than the amount of starter, and equal to the amount of water)
  • 25-200 grams filtered water (equal to or greater than the amount of starter, and equal to the amount of flour)

Instructions

  • Measure 1 TBSP (25g) of sourdough starter into a bowl on a kitchen scale. Note the amount by weight in grams.
  • To maintain a small starter: Add the same amount of filtered water by weight to the starter. Stir to combine. Then add flour and mix until no dry spots or lumps remain. Let feed at room temperature for an hour or two, then transfer to the fridge.

To scale your starter up for baking

  • For a mellow starter (levain): Measure 1 TBSP (25g) mature sourdough starter into a bowl on a kitchen scale. Add 75g-200g water (depending on how much starter your recipe calls for) and stir to combine. Then, add the same amount of flour by weight as you did water. Stir until no dry spots or lumps remain. Cover and let feed at room temp until it passes the float test.
  • For a sour starter: Transfer all of your small, mature starter (75g) to a bowl. Add 75g water, stir to combine. Then add 75g flour and stir until no dry spots or lumps remain. Cover and let feed at room temp until it passes the float test.

Video

Notes

  • How quickly your starter feeds and when it’s ready to bake with will depend on the ambient temperature and the temperature of your starter, water, and flour. Cooler ingredients = slower feeding. Room temperature ingredients = faster feeding. You can always check if it’s ready by dropping a small amount in a glass of water. If it floats, it’s ready to bake with. 
  • To calculate how much flour and water to add to your starter when you want to scale it up, take however much starter your recipe calls for, divide it in half and add 20. That number is the amount of water and amount of flour you should feed 1 TBSP of starter with. You will use most of the starter in your bake, and have about 25-30g of starter left to feed. It will become your new starter.
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pet

Hi Rebecca, thank you for posting this; it is so helpful. I too was getting way too much discard–good for the compost barrel but expensive compost. Thanks also for switching from volume to weight. I wish all online sourdough recipes specified that oz is weight and not volume. I noticed though that you change from oz to g, sometimes listing both in the same sentence and sometimes using one or the other. It would be exceptionally helpful to this reader (who was introduced to sourdough baking this summer using grams) to switch all your measurements to grams or at least… Read more »