Like a lot of other cultured foods, such as yogurt, sour cream, and others, sourdough is made with a live bacterial culture, called a starter. The starter acts in place of the yeast in normal bread, and helps the dough to rise. It’s also what gives sourdough its sour taste. However, because it is a live, active bacterial culture, you have to maintain it.
Starting a Culture from a Dry Starter
Follow the directions on the package, but it typically involves adding gradually increasing amounts of a 50/50 flour/water mixture until you get the volume you need. You can buy all sorts of varieties of starters, from New England, to San Francisco, even Gluten Free!
Starting a Culture from a Wet Starter
If someone you know owns a starter, all you need is a tiny amount of it to start your own culture. To get it to a useable size, put the culture in a non-reactive container, like a mason jar, and add a 50/50 flour/water mixture. You can add the flour mixture up to the size of the initial starter. So, if you have a tablespoon of starter, add a tablespoon of flour/water. The next day, 2, then 1/4 cup, 1/2 cup, and so on until it’s the size you want. I usually keep 2 cups of starter around.
When you’ve added the mixture, leave the container out at room temperature for 24 hours. The culture breaks down the starch in the flour, and turns it into CO2, so your mixture will bubble, then expand, then contract over that 24 hours, so make sure your container has a lot of head space to avoid a spilly mess.
Maintaining a Sourdough Starter
If you leave your starter at room temperature, you will need to feed it every day with 1-2 tablespoons of flour/water.
If you’re only using the starter once a week or so (like me), you can keep the starter in the fridge. The culture will go dormant, and will wake up when you add it to a recipe. After a little while, you’ll see a clear liquid appear at the top, just stir it back in. Unless you get green mould on it, it’s still fine, and should smell sour.
If you use the starter very infrequently – less than every 1-2 weeks, you can store it in the freezer. The bacteria won’t die, they’ll just freeze. When you take them out of the freezer, let them thaw, and feed them when they’ve thawed out.
There are a bazillion recipes online for sourdough bread, muffins, biscuits, pancakes, and more. You’ll start to find excuses to use your starter, and your house will smell like fresh-baked bread all the time! However, make sure you give the recipe lots of time to rise. My first few attempts I tried to cut the rising time down, and ended up with flat, chewy bread. Give your dough lots of time to rise, and it will be phenomenal! Make sure when you use the starter, you replace with flour/water mixture until it’s back to size again.