In the never-ending plight to live healthfully, one thing is for sure: The more natural something is, the better... especially when that something is going into your body. Natural food stores and farmers markets make it easier and easier to shop for good, whole foods, but as far as ready-made products -- refrigerator meals, dips and baked goods -- it's nearly as easy (and much more rewarding) to make them yourself. Sourdough starter is an excellent place to start.
While your first sourdough starter will take a couple of days to get going, after this first two to three day period, it will be ready to use for things like sourdough loaves, sourdough crumpets and even sourdough cinnamon rolls, and can be used again and again for different sourdough recipes, provided you continue to feed it.
Different methods for making a sourdough started can be found all over the Internet; many include adding things like grapes or potatoes, natural foods that provide extra sugar to the yeast. Your only problem with using these methods is that, with hundreds of forms of yeast out there, you might be cultivating a kind of yeast that doesn't thrive that well on flour.
Once the yeast has eaten up all the sugar from the grapes or potatoes, it's no longer a happy yeast. Your best bet is making sourdough starter from nothing more than flour and water. It might take a bit longer, but your starter will be better for it.
Simply combine 1 cup of warm water and 1 1/2 cups of organic flour -- white, whole wheat, or white whole wheat -- in a clean glass jar. Cover with cheesecloth, and keep in a warm place -- about 80 degrees, but no warmer than 85 -- for 24 hours. The natural yeast from the air will be drawn to the flour and settle into the mixture. After a day, remove the cheesecloth and replace it with plastic wrap. Leave the jar in a warm place for 2-3 days, stirring the starter several times a day. As soon as it's foamy and full of bubbles, your starter is ready to use!
Once you've made a starter, take good care of it: Sourdough starters impart more and more flavor the longer they live. Store your starter in a jar in the fridge, and be sure to feed it weekly, whether or not you're baking with it. Add equal weights of flour and water to approximately double your starter each time you feed it, generally after baking a fresh new loaf. If it starts to get unwieldy, you can always give some to a friend... nothing says friendship like a mason jar of live yeast cultures!