5 Things You're Doing Wrong with Your Sourdough Starter

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An interview with Jim Lahey and Maya Joseph, authors of the new Sullivan Street Bakery Cookbook

Jim Lahey, owner of New York’s beloved Sullivan Street Bakery, upended the food world in 2009 when he published his first book, My Bread: The Revolutionary No-Work, No-Knead Method. The title is self-explanatory: this is the simplest bread a person will ever make, but also one of the most impressive. The kind that can be whipped up with a finite amount of effort (it’s mostly about timing the rising of the dough) but will cause anyone who eats it to stop mid-chew and ask (mouth full), “You made this?” It’s also one of the most popular recipes The New York Times has ever published.

That Lahey recently came out with a second book is no small thing. And he seemingly has his finger on the pulse of the home-baking world because this one’s all about baking with a homemade sourdough starter. Sourdough starters have been called “America’s rising pet,” but the phenomenon is also global—there’s a sourdough “daycare” in Stockholm’s Arlanda airport that will watch over a traveler’s fermented friend while they’re away. Starters can be ordered in the mail, or better yet, gotten from a friend, but there’s nothing quite as satisfying as concocting one yourself.

Below, a streamlined version of my conversation with Jim and Maya about what I’ve been doing wrong, starter-wise, and the tips and tricks for how to get it right.


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You're Being Impatient

Rachel: Using my own experience, I’d like to ask you guys some questions and go a little bit deeper than you do in your book, about how to make a sourdough starter properly.

So here we go. Let’s say a person refreshes their starter, and it goes through the blooming process, and then they refresh it again, and it doesn’t bloom; it just separates into flour and water. What would you say is going wrong?

Maya: The separation into flour and water will happen no matter what, whether there has or hasn't been a bloom. Usually, the second bloom happens a lot faster (half of the time, or even less) than the initial bloom. The whole thing—rise, bloom, collapse—happens on super fast-forward speed, compared to round one. So it is entirely possible that the bloom has happened and you didn't see it. This has definitely happened to me. I’d just refresh the starter again and watch it more closely, looking for some sign of bubbles and a healthy (yeasty, champagne-like) smell.

Jim: I’d add patience. Do not refresh your starter again unless it smells like stinky feet or cheese. Don’t throw it away either. Blooming can take as long as three days, but it usually happens when we’re not watching. Then repeat the whole cycle again.


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You're Not Refreshing the Starter Enough Times

R: When the starter seems to be refreshing it also seems to be working. Why is it that when I went to make the biga (the stiffer dough that’s used in the book instead of a liquid leaven), it didn’t triple in size like it should have? I’ve tried this twice now.

M: I can tell you what I think, and then Jim might have a different opinion. It sounds to me like maybe the starter, even though it’s working, isn’t strong enough. The biga should be tripling in size, but if it’s not and it tastes sour, it sounds to me like there are bacteria or yeast in there that are doing something, but there aren’t enough of them to make the biga grow. So I would tell you or anyone else to refresh the starter a lot more times, over and over again, and then try making the biga again in the hopes that it’s building up an even stronger population.

You can also try soaking a vegetable with bloom on it in water, and then use that water to make your starter. The best place to find bloom is at the farmer’s market, especially on the leaves of kale, cabbage, or broccoli. It looks almost like ash, or like a white film. When you rub it with your fingers, it comes off. This is different from dust, though, which will come off onto your fingers. Bloom just disappears and doesn’t need to be washed off of a plant before consuming it.

J: A sourdough culture is a fungus, like a mushroom, maybe even more primitive than a mushroom, but it’s growing in a substrate of a mixture of flour and water. To get the culture that consistently and reliably does this work of causing dough to rise, or bread with gluten to rise, or to make beer, or to make wine, you need time. All flour will contain the necessary natural yeast to cause natural fermentation, but sometimes it’s just a matter of culturing it.

You’ve made yogurt once or twice in your life, right? You take some milk, you scald it, cool it down and when it’s kind of cool you put in that teaspoon of yogurt from a commercial batch of yogurt. You put it in your oven with the light on overnight, and in the morning you have a bowl of yogurt. In the same way, bacterially, things happen very quickly, but with getting yeast sometimes it requires a multiple refreshing for the starter to develop. You’ll notice as time goes on the more you use your starter, the stronger it should become.

You're Keeping the Starter Too Warm

R: When I first tried this, it was at the end of the summer, and I figured that must be the best time for a starter, right? Nice and warm? It seemed to bloom really quickly.

M: Actually, the hotter the climate the harder it is to get things to happen with just a few refreshments. The problem is the balance of what’s growing. Because the hotter temperatures favor the kind of bacteria that love heat, they tend to out-compete all of the more delicate yeast and bacteria that like cooler temperatures. So once they out-compete the stuff that you really want, you have to work harder to get the good guys back.

J: Temperatures play a huge role. The yeast and bacteria that we do want typically form at lower temperatures, between say 60 and 65 degrees. That would be the ideal temperature to hold your starter at for the sourdough to form.

R: Do you have a refrigerator that you set to this temperature specifically for this purpose?

J: No, I don’t. But if you have a wine fridge and you leave it at 59 degrees or something like that, that’s great. In which case you might leave your flour-water mixture in there for one week. What ends up happening is that the conditions will favor certain microbes to flourish and be happy, and other microbes won’t do that well. But with each successive feeding, there are changes in the liquid that you make. The pH changes, and when it changes it becomes a catalyst for other microbes to awaken. It’s like taking care of a garden. Sometimes you have to be patient more than anything else.

R: So since you’re not using a wine fridge, what do you do?

J: I find a cooler spot in the house to keep the starter. You can even rotate it in the fridge periodically. Obviously, when something gets cold it takes a long time to heat up, but maintaining this temperature range will be good for the dough. The idea with sourdough is that you’re creating this Mother, this thing that will keep giving birth or providing the energy, the seed, the life, for any successive bread that you make.

R: So once you have that starter covered and in the fridge, and you bring it out to refresh it, do you need to let it come to room temperature first?

J: No. Sometimes if it’s a closed jar I’ll shake it up vigorously, wait a couple seconds, see whether or not the lid as a result of my shaking is beginning to buckle or pop a little bit, and then I’ll open it up. If that first aroma that you get smells like champagne, like when you pop open a bottle of champagne, or upon opening of the jar it begins to fizz like a carbonated beverage, you’re golden. You’ve got it. That’s a great way to be able to study your starter. If it smells like vinegar, you’ve probably got some of the right bacteria, but you might not have enough of a good flora of yeast yet, and it just means refreshing again before using it.


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You're Using Your Reserve Biga From the Fridge for a Recipe

R: So after someone has taken all of these steps and made a proper biga, and they’ve stored it in the fridge, can they just take it out and use it for one of the recipes in the book?

M: You would want to refresh that biga first. Just like with a starter, you’d want to take a pinch of the biga you’ve been storing and make a new one with it. What you’re storing is basically the reserve, and then you would in turn store the new one and get rid of the old one.

J: But in addition, if you’re desperate, and you’re doing an overnight fermentation, you could use a tiny little piece of that biga in one of the recipes that require five or ten grams of sourdough, for example, because the ratio of that little bit of starter in relation to the added ingredients of flour and water is so low, so miniscule, that you do inadvertently refresh it. But if you were to use too much of that older biga in a finished dough, you won’t have a dough that’s stable because the pH will be kind of wonky. It will be too acidic.

You're Using the Wrong Flour (Unlikely, But Not Impossible)

M: If you're not sure that your starter is blooming at all the second time around, there might be a very low microbial count in the starter. You could keep refreshing and see if it perks up—sometimes it takes seven or eight refreshments to build up a bigger base, or you could start over and try a different flour brand. Microbes on flour vary wildly from batch to batch, so if you're not having any luck, it's worth trying a different one.


Courtesy W. W. Norton & Company, Inc.

Jim and Maya's Biga Recipe

70 grams (scant ⅓ cup) room-temperature (65 to 70 degree F) water
10 grams (scant 1 tablespoon) refreshed fermented starter
100 grams (½ cup plus 3 tablespoons) unbleached all-purpose flour
0.1 gram (a tiny pinch) fine sea salt

Mix together the water and the refreshed starter in a small bowl. Add the flour
and a few grains of salt. (Use just a tiny pinch, please—a bit of salt will speed up fermentation, but a heavy dose of salt will slow it down.) The dough will look lumpy, uneven, and small. Cover the bowl and prepare to wait about 24 hours for it to triple in size. Don’t be dismayed if nothing happens for the first 12 hours—it takes a while to get going, but once the fermentation starts, it will take off, and it is likely to grow more in the final 4 hours than it did in the first 16.

Poke at it and taste it—a fully fermented biga is pleasantly tangy with a fantastically airy, spongy, viscous structure. It will feel tacky, and it will taste and smell deliciously yeasty with a gentle smack of tartness—a bit like beer, but without any bitterness. At this point, it’s ready to use. You may note color changes in the biga as the top layer dries out and oxidizes a bit; this is perfectly fine and to be expected.