How to Make Sourdough Starter From Scratch With Just Two Ingredients
The idea of a sourdough starter—a live culture of wild yeasts that you feed, using it to “start” breads—can seem intimidating. But a sourdough starter requires just flour and water. To make one, all you need is two ingredients, a digital scale, and about five minutes every day for up to a week. The result? You’ll be able to bake better (read: more complex and delicious) fresh-baked breads.
Millennia ago, sourdough is what the first bakers made. If you feel intimidated, remember this: people were making it since long before we knew what yeasts were, since before we had today’s modern advantages of packaged organic flour, digital scales, and tap water.
Yes, it’s a project. Yes, you can do this. It just takes a little time and patience: roughly half an hour of work spread over four to seven days.
Before we delve into process, let’s cover some basics. Bread is fermented, like wine, kombucha, or kefir. Yeast initiates this fermentation. Sourdough is bread that has been fermented using wild yeasts, meaning invisible yeasts naturally occurring in the environment: floating in the air inside and outside, coating surfaces, and even existing naturally in flour. Yeast from the store-bought bag is different. This yeast contains just one strain. When you make sourdough starter, you’re calling on many wild yeasts, meaning many strains.
Using many strains makes for a complex fermentation that can’t be attained with commercial yeasts. In short, employing a sourdough starter makes great bread possible.
To begin, you’ll need a scale, mason jar (or another loosely sealable container), water, and unbleached organic white flour. Some starter recipes call for other flours, like whole wheat or rye, but we’re going to keep things simple with white. It is very important, though, to stick to unbleached organic white flour. This ensures that no unwanted chemicals will hamper the gentle development of our starter.
Using your scale, measure 150 grams of flour and 150 grams of warm water. Add them to your jar. Mix with a spoon until you have a uniform beige concoction. Leave the jar uncovered for about an hour, then place a cloth over your jar and loosely cover.
Now, wait until the same time tomorrow.
Over the first 24 hours, wild yeasts have been working. They are slower to act than commercial yeasts, but they’ve kicked into steady gear. Our next step is to do something we’ll do each day until the starter is ready in close to a week: we feed it, which allows it to grow stronger.
This process begins with a step that might seem counterintuitive. At this point, we must discard well over half of the starter—all but about 80 grams. (To calculate the weight of your starter, subtract the mass of a clean mason jar from the mass of the one holding your starter.)
Next, add 100 grams of water and 100 grams of flour to the starter. Mix well. Leave uncovered for about an hour. Set aside until the same time tomorrow.
On day three, we repeat this process. We also repeat the process on day four. By then, you’ll notice the starter has developed a pungent tang. It will smell like putting your nose directly to a fresh slice of sourdough, only more so.
We continue the daily discarding-and-adding until the starter is ready. There are many variables shaping when that will be, including temperature, environment, and flour type. Allow for some flexibility. If you dutifully feed your nascent starter every day for five to seven days, it should be ready.
How will you know when? It will be gooey, bubbly, quicker to rise up your glass, and develop a pungent smell just a handful of hours after feeding.
Congrats! You now have homemade sourdough starter. You’ll probably notice that you’ve developed something of an understanding of your starter’s behavior: what it needs, and how how it changes over time. Stored in the fridge, your starter will still require the same feeding, only weekly rather than daily. And instead of discarding excess starter, you can now use it as the leavening to begin, or to “start,” a fresh loaf of sourdough bread (or sourdough stuffing).