As I mentioned in my first Sourdough post, you can make your own sourdough starter, like I did, purchase a starter, or get some from a friend who has one going. The instructions I chose to follow to start my own sourdough are on the kitchn website. I found the day-by-day instructions very reasonable to follow. I recommend these instructions to anyone who wants to try to make their own starter. If you want to purchase a starter, you can get dried starter in a packet (with instructions) from Cultures for Health. You can also find someone who will give you a scoop of their starter so that you can begin to grow your own.
You will need to find a glass bowl or other glass container (as glass will not react with the acidic sourdough) with a lid or cover, big enough to hold at least 4 cups (1 quart), and with an opening large enough to allow you to add flour and water, and mix, and reach in to scrape the sides. Something like this pyrex bowl could work, or there are these great silicone covers, which you can put over a bowl that does not have its own lid (such as the smallest one of these—I love these bowls).
Once you have an established starter, you will need to feed it AND use it regularly. If you do not, those poor little yeast organisms will drown themselves in the alcohol byproduct of their metabolism. Just to keep the starter alive, you should feed it at least once a week with equal parts flour and filtered water (no trace chlorine, which kill it), after first removing a significant portion of the starter from the vessel. The portion you remove will make lovely sourdough goods for you, whether bread, or waffles, or crackers or whatever. (If you need to discard but cannot bake right now, you can toss or compost.) If you are planning to do some baking, or make a double batch of waffles, you might want to give your starter an extra feeding or two to bulk it up. I don’t always remove starter with each feeding when I am trying to bulk it up for expected baking. Just be careful to always leave around a 1/2 cup or so when baking, so that you can continue to maintain your starter.
If you have a nice cool place (generally around 45-55 degrees, you can keep your starter there rather than the fridge. I do not, so I keep mine mostly in the fridge, taking it out to warm up before and after feeding it, and before using it to bake, so that it has a chance to be thoroughly active. I will sometimes leave it out for a day two, while I am giving it multiple feedings, during a period of heavy use. When it is out and active, leave it covered only loosely, so that the starter can both breathe and expand (it can double in size, and then fall). Close it more tightly when you put it in the fridge, so that it will not dry out. Remember that the warmer your starter is, the more active, the more it will need air, and the more frequently it will need to be used/discarded and fed.
For additional reading, I recommend two little paperbacks that are easy to get from Amazon: Baking with Sourdough by Sara Pitzer, and Simple Sourdough by Mark Shepard. They are very short, and go over the basics of sourdough in an accessible way. Online, there are many articles, blogs, and discussion boards devoted to sourdough. Cultures for Health and Breadtopia are great resources. I have also enjoyed sourdough (and other) posts on the Nourished Kitchen blog, and the kitchn website, where I found the instructions I followed for my starter.
Despite what you will read from folks concerned about getting precise, reproducible results, once you establish a healthy starter, sourdough is very forgiving. Plus, it is just bread—or waffles, or whatever—and if it doesn’t come out quite right the first time, you will probably still be able to eat the results. Then, just try again a little differently. The yeast organisms floating around your environment will be different than mine, and will give your starter a subtly different behavior and flavor. Your oven, the temperature of your kitchen and fridge, the flour you use—they will all be different. So, your results will be unique! It is a little journey.
I have also noticed that the goods I produce with my starter initially were far more sour tasting than what I am getting now. I started my culture in October, I believe, and it is now the end of December, so it seems to have changed a good deal over the past two months or so. I feel like I am caring for a pet or growing a little life—sometimes I am tempted to give my starter a name, though I have not yet. It seems almost to have a personality, and I have certainly developed a fondness for it.
If you come up with a good name for yours, please share. :)