Introduction: Grow Your Own Wild Sourdough Starter

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Creating life from thin air may make you feel a little like Dr. Frankenstein, but there's really nothing sinister, or hard, about it.

My family made our first batch of sourdough starter as a biology experiment. The method we chose was devised by bread-baking fan (and microbiologist) Debra Wink. She did a study which determined that adding pineapple juice to the traditional flour and water keeps the starter's pH levels just right for suppressing bacteria and encouraging yeast growth. The entire process takes four or five days, but most of that time your starter needs very little help from you. The little micro-critters do all the work!

Although we only expected to use it once or twice, our original batch kept us in bread and pizza dough for many years. Keep reading to see how we did it -- and if you'd like to try some more of our family-friendly food experiments, check out my book Edible Inventions from Maker Media!

Step 1: Gather Your Materials

· 1/2 cup unsweetened pineapple juice

· about 1 1/2 cup whole wheat flour

· about 2 cups water

· glass container with top

While you can use white flour, you'll get the best results from whole wheat, which has its own yeast spores ready to grow.

A glass container is the best way to store your starter between uses. It won't react with the acid in the starter, and since you can see what's happening it will make it easy to tell when your starter needs some attention.

If the mouth of the container is wide enough, you can mix up the next batch of starter right in it. Just pop it in the fridge when you're done, with a loose covering.

Step 2: Start the Process

Combine 2 tablespoons flour with 2 tablespoons pineapple juice. Stir the mixture well, then cover with a piece of plastic wrap. Let it sit for 24 hours at room temperature.

Repeat these steps on each on Days Two and Three, adding another 2 tablespoons flour and 2 tablespoons pineapple juice to the bowl. By the second day, you should start to see bubbles. That's the live yeast, producing carbon dioxide. It's those bubbles that make the dough rise!

Step 3: Nurture Your Growing Pet

On Day Four, stir the mixture in the bowl, which should be nice and frothy. Here's the part I like the least -- having to throw some of the starter away. To keep the yeasties growing, you've got to give them some more food to eat, and get rid of some of the old stuff. But don't worry, once you've got your starter going strong, you'll be using every bit.

For now, measure out 1/4 cup of the starter and discard the rest. Take the remaining 1/4 cup and stir in 1/4 cup flour and 1/4 cup water. Let this new mixture sit for 24 hours at room temperature.

Repeat these steps for another few days, until the mixture has doubled in size and smells like a brewery. Then put it in its glass storage bowl or jar and put the lid on loosely, to let any pressure from the carbon dioxide bubbles to escape.

Unless you're using it every day, store your starter in the refrigerator. Leave it there until you're ready to start baking.

Step 4: Care, Feeding and Use of Your Starter

Most sourdough recipes require you to reawaken your starter a few hours before you start to bake. The way to do that is to make a "sponge." I usually pull out my starter the night before and make a sponge overnight in a large glass bowl. That also gives me a chance to wash out the starter container. I loosely cover the bowl with a piece of plastic wrap, which I save to cover the dough the next day.

To make the sponge, take the starter and mix in one cup of water and one cup of whole wheat flour. Let sit for a few hours or overnight. The sponge is ready when it's bubbly all the way through. The longer it sits, the more sour your dough will become. Measure out the amount you need, mix in another cup of water and cup of flour to what's left, then put it back in the storage container and pop it back in the fridge. If you don't use your starter for a couple weeks, scoop some out, throw it away, and add more flour and water. That will help it stay fresh.

You may find a layer of dark liquid start to form in your starter. That's called "hooch." It's a little alcohol produced by the yeast (just like in beer-making). You can pour it off and add an equal amount of water in its place, but most bakers just stir it back in. It depends on how tangy you like your sourdough to be.

You can use your sourdough starter in any sourdough bread recipe. Just be sure to handle the dough more gently than with regular yeast. Sourdough also makes a great pizza dough. Enjoy!

Step 5: Yeast Experiments

Bread is nice, but you can also do lots of fun experiments with yeast. Take a look at it under a microscope--the cells are nice and big, and if you're patient you can watch them bud and multiply! Or take a little starter, feed it and add enough water to make it very runny. Then pour it into a clean empty soda bottle. Stretch a rubber balloon over the top and wait a bit. Soon the carbon dioxide given off by the active yeast will inflate the balloon. Homegrown science!

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