How to Make a Sourdough Starter From Scratch

sourdough starter
It's easy to make your own sourdough starter in just a few days with all-purpose flour and water. Flickr/JoLynne Walz Martinez


As panic-buyers scoop up everything from toilet paper to oat milk, one unexpected item is now also tough to find: yeast. This fungus may not be a pantry staple for the masses, but for the growing number of self-isolating bread bakers — a population that likely spiked between March and April, according to Google Trends — yeast is an absolute must-have.

But with sourdough bread, you don't need store-bought yeast. Sourdough bread requires wild yeast, which you get from a sourdough starter — a fermented dough with wild yeast and lactobacilli bacteria. Many people get sourdough starters from friends or family — there are stories of sourdough starters being passed down for generations. But you don't have to get a starter to enjoy fresh-made sourdough bread; you can easily make one at home.

How? Simply harvesting the wild yeast from the flour. When you let a flour-water mixture sit around for several days, that wild yeast will activate by feeding on the sugars present in flour.

To make a sourdough starter you need three simple things: flour, water and time. The latter is why so many are jumping on the bread-baking bandwagon now. Bakers need daily time at home to "feed" the starter every day for about a week — and time at home is perhaps the only COVID-19 constant.

Ingredients and Equipment

  • All-purpose flour
  • Water
  • Scale or measuring cups
  • Glass bowl
  • Fork
  • Clean towel or plastic wrap
  • Rubber band

You can use other flours, but all-purpose flour tends to behave more predictably, and is therefore the easiest option for new bread bakers. Author and blogger Emilie Raffa from The Clever Carrot — a food blog that went viral from its 2014 sourdough bread guide — recommends skipping organic flour. She says filtered or tap water is fine, as long as the tap water is chemical and chlorine free.

Step 1. Making the Starter

  1. Combine 1/2 cup of all-purpose flour and 1/4 cup of water in the glass bowl.
  2. Use a fork to stir the ingredients vigorously until it looks like sticky dough.
  3. Scrape down the sides of the bowl and cover with a clean towel or plastic wrap secured by a rubber band.
  4. Place it in a warm spot, around 75 degrees Fahrenheit (23 degrees Celsius), for 24 hours. (The Kitchn recommends the top of the refrigerator.)

Step 2. Feeding the Starter

After 24 hours, it's time to feed your starter. First, check your starter. If you notice bubbles, you're in luck. This indicates the starter is fermenting — which means wild yeast is on the way. (If you don't see bubbles right away, don't worry: Some starters take longer to ferment based on your kitchen conditions.)

  1. Discard about half of the original starter.
  2. Add 1/2 cup of flour and 1/4 cup of water.
  3. Mix with a fork until starter is smooth.

Raffa says it should feel like "thick-ish batter," so add water accordingly. Once you're finished, cover and set aside for 24 more hours in the same warm spot. Repeat this step for five or six more days. During this time your starter should start smelling pretty sour — that's totally normal.

Step 3. Start Baking With Your Starter

After about five to seven days of feeding your starter, it should be twice its original size, filled with bubbles, smell sour and taste vinegary. These four signs indicate it's ready to use to start baking sourdough bread — a process that can take anywhere from three to 12 hours, depending on your starter and ingredient temperatures. (Check out the Clever Carrot's viral sourdough recipe for bread-baking inspiration.)

Step 4. Maintaining and Feeding Your Starter

If baking is a one-time trial, you can toss the extra starter and enjoy your bread. If you plan to continue baking, though, you can keep the starter alive by following a starter maintenance schedule, which is a simple, scaled-back version of step two: Place the starter in a clean glass jar and store it in the refrigerator where you'll repeat the removal and feeding process about once a week. If you bake more regularly, store the starter at room temperature and feed it once or twice per week. When you follow the maintenance steps properly, your starter can last for years — or longer.