Sourdough is the natural choice for zero waste bread-baking.  All it takes is flour, salt, and water, and you get a beautiful crusty loaf for a fraction of the cost of buying bread. But how on earth do you make a sourdough starter?

20 Second Summary

Mix flour and water in a glass container (equal parts by weight) and let it sit overnight.  The next day, pour out about half of the mixture and replace it with new flour and water.  Repeat until it’s consistently doubling in volume after you feed it. It should take a week or a little less if it’s warm where you live.  Once it’s active and bubbly you can keep it in the fridge but if you leave it out make sure to feed it daily (same deal, pour some out, add some flour and water).

What You’ll Need

• Water (that’s been boiled previously or filtered)
• All Purpose Flour
• A container with a lid, preferably glass or plastic
• A scale of some sort (or the knowledge that 1 cup of flour weighs about the same as 2/3 cup of water)

Day 1​

NOTE: the vagueness of these instructions is intentional. Sourdough is resilient, you’ll have a hard time messing it up, use whatever measurements work for your container.

Measure out your flour and water in a 1:1 ratio by weight and mix well with a wooden or plastic spoon.  I use water from a water kettle because I know it’s been boiled.  This is important because most tap water is chlorinated specifically to kill the little guys we’re trying to make a home for.  Don’t use hot water though, you’ll kill the little guys just as effectively as the chlorine you’re trying to protect them from. 

Leave that mixture loosely covered overnight.

Your new starter is most sensitive to temperature. Too cold and it won’t grow very quickly at all. Too hot and you’ll kill the stuff.  A warm room temperature is ideal for the first week.  

Day 2-6

Pour out half the starter and replace the flour and water in a 1:1 ratio. For those of you wondering what do with the sourdough starter waste: make pancakes (or anything else that needs flour and a liquid). Savory pancakes, sweet pancakes, scallion pancakes, you get the gist . 

Leave that mixture loosely covered overnight.

When Is It Finished?

Once your starter starts consistently doubling in volume after feeding it you’re good to go.  For people in warmer climates this will happen sooner than people who try this somewhere cold. 

What’s Going On?

You’re growing millions of living breathing pets!  The flour and water mix that you start with is a perfect home for airborne yeasts.  These little creatures are everywhere just floating around in the air and some of them find their way to your starter and make it their home.  During the first week you’re slowly building a community of healthy yeasts by constantly giving them new flour to eat.  Eventually you’ll knead them into a loaf where they’ll breathe out as they eat.  These millions of little exhalations are the bubbles that make your loaf rise!

Please comment with questions (we’ll answer them ASAP) and share this with your baking buddies!