A sourdough starter is a culture of yeast and bacteria that will leaven bread. To leaven bread with it, you take a piece if the starter and mix it into your dough. This inoculates the dough- instead of adding dried yeast, you’re adding active yeast that is living in that piece of starter. Starter also contains beneficial bacteria. These bacteria create acids when they consume the starches in the grain. This is what gives sourdough it’s sour flavor, as opposed to a bread that is only leavened with added dried yeast and thus doesn’t develop that pleasant tang.
To maintain as starter you must keep feeding it. To do so, you will essentially inoculate a new starter each time with a little piece of the old one. The microorganisms in the old one will eat the fresh flour and water mixture and multiply. They excrete gases and acids as they eat and multiply, which is what causes the bubbles in the dough and the flavor in the bread. Eventually, the starter will be saturated with yeasts and all the food in it (from the flour) will have been consumed. Then you’ll take a bit of that old starter and use it to feed a new one.
If you’re looking to start a starter, you can absolutely adopt a bit of starter from a someone who already has one going. It may take a little bit of time for it to get used to you and its new environment, but it will settle in pretty quickly and be useful for baking almost right away. However, its fun and simple to start your own starter. Also handy if you don’t know anyone who has one going. Starting from scratch gives you some experience with monitoring fermentation, which is a really important part of your bread-baking toolkit. Here’s how to do it.
How to Make a Sourdough Starter
All of the yeasts and bacteria that are needed to make bread occur naturally on your hands, on wheat, and maybe even in your kitchen already.
To start a starter, all you need to do is mix some flour and water together and wait for it to ferment.
For the flour, you want to use unbleached flour, preferably organic. You are cultivating beneficial yeasts and bacteria, so you don’t want a sterile environment. You also want some of the good brown stuff in there- bran and germ. It’s as healthy for your culture as it is for you. Either look for ‘T-85’ which has some of the bran and germ in it, or mix a 50-50 blend of bread flour and whole wheat flour. Cairnsprings Trailblazer is a great flour for this, also I love this one from Carolina Ground. If you’re using whole wheat, look for stone-ground whole wheat, which will have all of the parts of the grain in it (some ‘whole wheat’ is just white flour with some bran blended back in, and isn’t really all the parts of the grain). I love this one from Camas Country Mill and this one from Grist and Toll. The fresher and more organic/regenerative, the better. It takes me much less time to get a starter going when I use fresh, whole grain to feed it. I also get a much healthier more active starter.
For the water, you want to use water that doesn’t have chlorine in in (for the same reasons that you don’t want bleached flour.) If you have chlorine-free tap water, that’s great. Otherwise, you can use filtered water. I usually save the leftover water I boil for tea or coffee. Boiling and letting it cool it removes the chlorine. You want the water to be warm- yeast and bacteria are much more active at warmer temperatures.
To Start the Starter
150 g (2/3 Cup) of warm, filtered water (about 85°F / 29 C°)
150 g (1 cup) of T-85 wheat bread flour, or 75 g (1/2 Cup) of white bread flour and 75 g (1/2 Cup) of stoneground whole wheat flour
In small bowl or jar, mix the flour and water well with your hand. Scrape any bits that stick to your fingers back into the jar. Keep the container somewhere warm. Cover it loosely, so that it can breathe.
Allow to rest in a warm place for about 48-72 hours, until you see bubbles in the mixture or on top and it smells sour.
Once you see those signs of fermentation, give your starter its first feeding. If there is any liquid on top, just pour it off and use the mixture underneath. That liquid is a normal part of fermentation and isn’t harmful.
To Feed the Starter
100 g (1/2 Cup) of warm, filtered water (about 85°F / 29 C°)
25 g (1 Tbs + 1 tsp) ripe sourdough starter
100 g (2/3 Cup) of T-85 wheat flour, or 50 g (1/3 Cup) of white bread flour and 50 g (1/3 Cup) of stoneground whole wheat flour
In a clean container, measure the warm water. Add the ripe starter. Add the flour. Mix well by hand. Scrape any bits that stick to your fingers back into the jar. Keep the container somewhere warm. Cover it loosely, so that it can breathe.
For the first week, feed the starter every time you see bubbles and smell that sour smell. After the first week, it should reliably start rising 3-5 hours after you feed it (as long as you’re keeping it warm.) After that, feed it once a day. It may seem to stop and start during the first week or two, just keep feeding it when you see bubbles and smell fermentation. It may take as long as two weeks for it to start being predictable.
Once you have a starter that rises and falls consistently you’ll be ready to bake sourdough bread.
You’ll have some old starter leftover after you take the 25 grams to feed the fresh starter. You can save this and use it in ‘starter discard’ recipes like crackers, cakes, brownies or cookies, or discard or compost it.
There are lots of other ways out there to start a starter. Some use fruit like grapes that has lots of yeast on the skin to jump-start fermentation. Some use fruit juice to give the microorganisms a boost of sugar to eat. Some use a tiny bit of commercial yeast. This is the one I have used several times (most recently after I left Tartine and wanted to get a fresh start-er). I love this method because it is simple and elegant and gives you a robust natural starter full of yeasts and bacteria that thrive on the wheat in your flour and in your particular environment.
If you want to watch me do it, I made some tutorials at the beginning of 2020, during quarantine. They’re on Instagram, but I also put them up on my website so they’re easy to get to. I have really simple and easy-to-follow instructions in my book, Baking Bread with Kids. If you’re an audio learner, here it all is on audiobook, and if you’re a super geek we get into deep detail in Bread Book.
Next week I’ll write my Country Sourdough Recipe, and then we can get to purple polenta bread and all the other myriad variations after that.