Many people think that sourdough refers to a style of bread — a crusty white loaf with big holes and a sour flavor. This San Francisco-style sourdough is famous thanks to bakers like Chad Robertson (of the Tartine empire). However sourdough can run the gamut of baked goods, from dense rye loaves to pizza crusts to croissants. Sourdough refers to the process in which bread and other baked goods are fermented or risen.
Nowadays bakers typically use a package of commercial yeast to rise their dough. Those lab-bred microorganisms work super fast and uniformly by converting the starches in flour to carbon dioxide, which gets trapped in the dough and creates the air pockets seen in bread crumb (crumb refers to the interior of the bread). Sourdough uses wild yeasts and bacteria — found in the air, on the flour, and on our hands — to do the same job, but much slower. This slower fermentation process produces more nuanced flavors — the sweet and acid notes associated with sourdough, and if properly managed — a more digestible product.
To bake sourdough bread (or pizza, or croissants), you need to maintain a sourdough starter. Anyone can create a sourdough starter from scratch, with one trip to the grocery store and about five minutes of work a day for approximately two weeks. After that, the starter will require regular use or occasional maintenance, and — Bam! you got yourself a collector’s item that can be shared with friends and family.
Yeast and lactic acid bacteria (LAB) like to eat sugar. Mixing flour and water together creates an all-you-can-eat buffet for the wild yeast and LAB in the kitchen environment. The microbes will gobble up the sugars (starch) and convert it into carbon dioxide and lactic acid. Happily fed, the yeast and LAB reproduce and take over the mixture. A healthy colony of microbes will thrive perpetually in the flour and water mixture as long as they’re kept fed (in the form of flour and water). Now it’s time to make delicious baked goods
- Rye or whole wheat flour
On the first day, mix together equal parts room temperature water and rye or whole wheat flour (I do 30 g and 30 g) in a clear jar. Stir to remove clumps of flour and thoroughly aerate. Loosely cover with a kitchen towel or lid (don’t screw it on).Check in on the mixture for the next few days. After 3-5 days, tiny bubbles should begin to form. Those bubbles are the sign that wild yeast and LAB have made their way into the mixture. This is the beginning of your sourdough starter.Once the bubbles appear, begin to feed the starter.
Feeding the Starter
Scoop out 50 g of starter into a clean jar. Add in another 50 g room temperature water and 50 g rye or whole wheat flour, mix thoroughly, and loosely cover. The leftover starter in the first jar is called the “discard”, which I save in a separate container in the fridge for other uses (it’s great in pancake batter). Feed the starter (the direction in bold above) twice everyday, morning and night, at roughly the same time. Once the mixture begins to follow a regular schedule where it doubles in size and then collapses back down in between each feeding, it’s ready for baking. I recommend feeding the starter twice daily for another week or two, in order to develop its strength and flavor.
Storage, Use, and Maintenance
Once satisfied with the starter (taste it throughout! The flavor should be a pleasant combo of acidic and fruity), seal it tight and store in the fridge until ready to bake with it. About 4-6 hours — longer if living somewhere really cold — before baking with the starter, take it out of the fridge and feed it. Once the starter has roughly doubled in size, looks aerated throughout, and floats when dropped in water, it is ready to bake. Take out the amount of starter required for the recipe. Don’t forget to reserve some of the starter and feed it, so it can be used for future bakes. Store in the fridge between uses.
To Increase or Decrease Starter Quantity
50 g each of starter, flour, and water gives me enough starter to bake a loaf or two of bread. If I need more, I can increase these numbers. If I'm feeding for storage in the fridge, I decrease to 30 g each. If I need a ton of starter, I feed a very small amount of mature starter to a large quantity of flour and water and let it rise overnight. For example, if I needed 800 g of starter, I would mix 400 g water, 400 g flour, and 20 g mature starter and let it rise for about 12-14 hours. Sometimes a brown or grey liquid will form at the top of the starter. This is perfectly fine. It’s alcohol from the fermenting process. Just pour it off and continue as normal. It is a sign that the bacteria are hungry, so simply feed the starter more regularly.
You cannot “kill” a sourdough starter. Even if the microbial colony in the starter dies, you can always coax more wild yeast and bacteria with fresh feedings of flour and water. So if the sourdough isn’t behaving, it’s a sign to feed it more regularly.
These are the basics to maintaining a healthy sourdough starter. If you have any questions at all, please reach out at firstname.lastname@example.org.