...But let's back up.
To make sourdough you need a starter: a flour and water mixture that contains the natural yeasts that will allow you to create bread. Depending on where you live, your starter will be unique, and it will also change and get better with time. Legend goes that the yeast in your sourdough starter is caught from the air, but I read somewhere that it's not the air, but the flour that contains the naturally occurring bacteria you need.
There are two ways to obtain a starter:
1. Ask a friend who bakes sourdough for some starter. I'm sure they'd be thrilled. This stuff multiplies fast.
2. Make your own: Here are instructions from the Kitchn, and King Arthur Flour. Creating a starter from scratch takes about a week. From then on, you can maintain it indefinitely.
Feeding your starter
A starter is a living thing, and needs regular feedings or it will die and the aim is to keep it alive. (They're really pretty tough, and even though I've neglected mine, its still going strong more than two years after I got a starting batch from a friend. So don't fret too much.)
SO you've got a starter, now what?
Most recipes call for a 100% hydration starter. This has to do with the ratio of water to flour in the starter. So a 100% hydration starter has a ratio of 1:1 flour to water. Simple right?
But remember when I mentioned that your starter may have ambitions for taking over the world? That's because every time you feed it, you need to use a 1:2:2 ratio. 1 part starter, 2 parts flour, 2 parts water. For example: Mix 50 g of starter, with 100 g of flour, and 100 g of water.
After mixing the starter with its food, set it in a big clear container with a lid in a warm place like the top of the fridge, and forget about it for 4-8 hours. The container should be large enough to contain at least double the volume of the starter + food mix because it will grow. Tip: If it's cold out, mix lukewarm water with your starter. Warm = faster growth.
The starter will double in size during this time, get bubbly, and smell wonderful. That's the yeast in action, bubbling away as it eats (that's what makes your bread rise). Once it's doubled in volume its ready to use.
If you leave the starter longer, you'll see it fall back down to its original volume because the yeast has eaten all its food.
|1) Unfed starter. 2) Starter just mixed with flour and water. 3) 7 hours later the starter has almost doubled.|
Maintaining your starter
If you're not going to make bread and you're just feeding your starter to keep it alive, just stick it in the fridge at this point. It can last a week or two in the fridge without feeding. If you are going away for longer, or need a break from bread baking, it also freezes well for months and can be revived after thawing with a feeding.
Some sites say you should feed the starter daily, and throw away half of it. What a waste! I recommend keeping it in the fridge unless you bake daily.
If you keep your starter in the fridge, just take it out and feed it once a week before baking and you're golden. You don't need to save much after each feeding: refrigerate 50-100 g for the following week.
Here's some math: 50 g starter + a feeding at a 1:2:2 ratio = 250 g starter for baking. 100 g starter + a feeding at a 1:2:2 ratio = 500 g starter for baking. You may want to reserve more or less depending on the recipe you plan to use.
Use a clean glass or plastic container for storage. Metal might react with the yeast.
Reviving your starter
If you've neglected your starter for a long time, a clear liquid may form on top. That's hooch. It's a mildly alcoholic by-product of fermentation. You can pour it off the top before feeding. Sometimes the starter can dry out on top, but there's usually enough starter underneath. Spoon away the hard stuff on top, and feed the remaining starter in a new container. One or two feeding's is usually enough to keep it happy.
I also keep a backup of extra starter in the freezer just in case.
Still have too much starter?
It happens to all of us. If you can't give some away, there are recipes that use unfed starter / leftover starter like pancakes, waffles, english muffins and all sorts of things.
Please give your starter a name, and feed it regularly. It might be more inclined to be nice to you.
Start from the beginning: Sourdough Workshop Index.