How to Make a Sourdough Starter

How to Make a Sourdough Starter

I've never been a fan of sourdough. Until I found out that what's called "sourdough" isn't, in fact.

When I learned what real sourdough is, I became a fan right away.

The truth is, in almost every case, what's packaged as sourdough is really just quick bread (made with active dry yeast) that's had some kind of sourdough flavoring added. Real sourdough, or slow bread, gets its rise and its flavor from wild yeasts.

Wild yeasts are kind of like magic. They just invite themselves to the party. When making a ferment, you don't have to add anything more than flour and water. Those yeasts will just show up — it's incredible, but true. And when baking with that ferment, you don't have to add packaged yeast to the dough. Instead, you mix in some of your starter: that little civilization which you feed and tend in order to keep it alive and strong forever (unlike Rome), unless you happen to forget about it and it falls apart and consumes itself (like Rome).

About the flavor: sourdough can be sour. But it can also be sweet (my preference). It just depends on what's happening in yeast politics that day. If everybody's starving or they've been stewing in there for a long time, the culture tends to run sour; if they all have plenty of new food, it tends sweet. There's plenty else to know about that, but this is enough to be getting on with.


1 scant part flour Straight glass jar with a wide mouth and lid*
1 half part water

* I like the Bubbies pickle jars. I think the jar I'm using now was made for mayonnaise.


Your basic recipe for every step of this process is going to be equal parts flour and water, by weight. Not volume. So, 50g flour wants 50g water. Choose whatever quantity you like; you could do 10g flour + 10g water, or 200g flour + 200g water — it doesn't matter. However, smaller starters are easier to work with, especially at first. And it's best if you don't fill your jar to more than half full (the lump is going to puff up to twice its size later). When it comes down to it, though, what matters is the ratio: half and half.

For those of us who end up doing everything by volume, memorize this instead: one scant part flour, one half part water. One scant, one half.

  • 1 scant c. flour
  • 1/2 c. water

That will give you roughly equal parts by weight. Roughly is okay.

How to Start Your Starter

Put the flour and water in the jar. Mix it. Screw the lid on and leave it on your counter.

Look at it.


Look at it.

Eventually you'll see bubbles in the dough, pressed up against the glass.

This may take hours or days: it depends on your kitchen, its temperature and its yeast population. But know this, yeast is everywhere. If you want to kickstart things with some active dry yeast, or honey, or raisins, or whatever, go right ahead, but they're not required. Flour and water is all it takes.

Once you see the very first sign of bubbles, scoop out half of the mixture, then replace what you removed with fresh flour and water.

  • 1/2 scant c. flour
  • 1/4 c. water

Why remove half? Because every time you feed a starter, it's best to double its weight. That way there's enough fresh food in there for the yeasts to work on so they don't start dying and eating each other. Sure, you could just double it without removing half, but then your starter would grow exponentially and subsume your kitchen. The only way to maintain a consistent volume from one feeding to another is to remove half first, then add half back.

Anyway, so you mix it up — all the bubbles are stirred in now, right? no bubbles anymore — and wait.

Voilà. More bubbles. Do it again.

And again.

Every time you see new bubbles, remove half and feed it again.

Keep this routine up until your ferment is puffing up to twice its size between every feeding. It's helpful to put a rubber band around the outside of the jar to mark its level; that way you can eyeball it as soon as it's doubled its volume. You know you've got a healthy, robust culture going when it's doubling itself multiple times per day. Even if your kitchen is cold, it should be able to do this. Congratulations! The civilization has officially flowered. You're ready to bake.

How to Store It

Put it in the fridge.

If you let your starter live on your countertop forever, you'd probably begin to resent it. A thriving starter is a demanding friend, never satisfied with what you give. Also, you'd waste a lot of flour, because every time you feed it, you're throwing away half its weight. But pop that thing in the fridge, and the yeasties slow way down. They're still in there, living and eating and growing, just in slow motion.

How to Revive It

Back when I was getting my routine for this figured out, I read that if you store a starter in the fridge for too long, eventually it will deteriorate and stop functioning. So now and then it's good to take the jar out and give the beasts some time to remember what life is all about.

Take the jar out of the fridge and set it on the counter. Forget about it anywhere from an hour to a day.

When it's warmed to room temperature, transfer it to a bowl and feed it.

Let the culture work on that until it's gotten good and puffy. Then transfer some of the lump back to the jar, feed it again and immediately stick it in the fridge. For example, if you like to keep a total of 2 cups in the fridge, here's what should go into your jar:

  • 1 c. starter from the bowl (give or take)
  • 1 scant c. flour
  • 1/2 c. water

I know, that makes for a little more than 2 cups, but whatever. It's about right. Put the jar back in the fridge and whisper, "Happy ice age, suckers!"

What about the rest of the stuff in the bowl? That's what you bake with. If you're not ready to bake, give it to the chickens. If there are no chickens, wash it down the sink disposal. In any case, this is your new routine from now on: take the jar out, let it warm to room temperature, feed it, let it puff up, feed it again and put it back.

When I'm on my game, I bake once a week (recipe here), and letting it revive that often feels like a good rhythm. But it's worth knowing that your ferment can live a surprisingly long time unattended. Should you happen to go out of town for a few weeks and forget to bring it with you (just saying, you might want to bring it with you), when you get back, you'll probably find a thick, brown, heavy-smelling layer of hooch on the surface. But scrape that off, and underneath you'll find the sweet, pale honeycomb stickiness of the healthy stuff, still alive.

Will it wait for you during your three-month European backpacking expedition, or die pining? Probably die, but who knows. I've killed one or two starters by accident, but I've never made a study of it. Happily, if you do kill it, you can always start another.

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