What is Sourdough?

by Heather

When people think of bread, they tend to think of that which uses commercial, or quick rise, yeasts. However, this type of bread has only existed for just over 160 years.

Sourdough breads are made with wild yeasts and bacteria. Three basic ingredients – flour, water, salt – come together in a beautiful symbiotic rhythm to rise the bread naturally, as has been done for thousands of years. The yeast and bacteria that exist on the flour grain and on the bakers hands get kick-started once the water is added to the flour. They begin digesting the flour, and a by-product of this digestion is carbon dioxide. The CO2 creates bubbles in the dough, which gives the bread its rise. Some bacteria even digest gluten, creating lactic acid which brings the sour to the sourdough. (An interesting side note: many people who are gluten-sensitive are actually able to eat sourdough with no digestive issues – this is due to that breakdown of the gluten protein, making it gentler on sensitive stomachs.)

To start, you need a starter. This is something you can either make yourself from scratch, or receive from someone else. If you don’t want to make it from scratch, I suggest reaching out on social media (NextDoor is a great way to find starter!) and simply ask: “Does anybody have some healthy, active sourdough starter I could have?”

Once you have a starter and it’s healthy and active, you add warm water and flour to begin your dough. It must rest after mixing, and this is called the autolyse. This allows the flour to fully absorb the water, to activate enzymes, and to begin converting the flour into simple sugars. It’s a hugely important step, one that takes about 30 minutes, but some autolyse for up to two hours or more.

After the autolyse, the salt is added. Salt adds flavor to the sourdough, and also gives the dough structure, improving its ability to hold on to the carbon dioxide. It slows fermentation, which is why it’s added after the autolyse. The salt is mixed into warm water and then incorporated into the dough completely. Then, the dough rests for 30 minutes.

Now begins the series of folds. There are countless techniques for this, and it comes down to preference. Personally, I prefer to leave my dough in the bowl as opposed to dumping it onto the counter. This makes far less mess and makes the folding steps simpler. I do a total of three folds, each resting for 30 minutes in between.

Then the dough sits pretty for 1.5-2 hours. This is called the bulk fermentation, where the gluten is allowed to relax and more complex flavors are developed. After this stage, your dough will be light and airy.

Folding and Shaping Dough

The dough comes out onto the counter and is divided and pre-shaped. A towel is draped over the loaves and they rest again for 30 minutes. Then it goes through its final shaping and is placed into baskets.

Now the dough goes through its final fermentation. This can either happen at room temperature just before baking, or in the fridge overnight. I prefer to do cold-proofing in the fridge overnight because it works better with my schedule.

When you’re ready to bake, the oven is preheated with the cooking vessel inside. Once it’s good and hot, the dough is flipped out of its basket, scored, and it goes into the shallow pan. I use a cast iron combo cooker. It’s amazing because the key to a golden crust that isn’t dry and over-baked is moisture. Commercial ovens have steamers that can maintain humidity within the oven, but home ovens don’t have that capability. In fact, home ovens are designed to remove humidity. The combo cooker works because the steam that is released from the first few minutes of baking becomes trapped and surrounds the dough as it bakes.

Taking the Lid Off the Cooker

A note about scoring: a nice deep score that is continuous around the boule, like a square or half-circle, allows the dough to rise upwards, creating an impressive looking loaf. Small, tight scores, like chevrons, won’t allow the upward rise and will instead create a loaf that is shorter and more compact, and the loaf will likely “self-score” (aka, burst open) somewhere. Scoring is recommended.

The lid of the combo cooker is removed after 15 minutes, and the loaf is allowed to bake for another half hour. It comes out of the oven and is tipped onto a cooling rack, where it crackles and snaps as it cools.

And those are the basics of sourdough! Please comment or email with any questions or experiences you want to share. I wish you happy baking!

Subscribe for more helpful sourdough content like this!

You may also like


Sourdough Discard Recipes: The Internet's Largest List (2020) — Leavenly April 24, 2020 - 2:08 pm

[…] Regular (or yeasted) breads use commercial yeast to get their rise, whereas sourdough breads use a starter to get their rise. Learn more about sourdough bread here! […]

Renee July 22, 2020 - 10:38 am

Where did you get your cast iron combination cooker?

leavenly July 22, 2020 - 10:53 am

Hi Renee! I got mine on Amazon and the price was great. You can find it here!


Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.