I like to use starter for my ciabatta, and actually for all of my breads.

Starter is a simple pre-ferment consisting of flour and water.  Many recipes will call for poolish, sponge, levain, or biga; these are all starters. Most of these starters are made in the hours before making the bread. A step that you can skip when using a sour starter that you already have on hand.

Starter is a way to produce natural yeast.

Where does the yeast come from? It is in the flour, the water, the air … it is all around us.  You are breathing it now.

To make starter, you mix equal parts of water and flour together. Yeast starts to eat the natural sugars that are in the flour and produces carbon dioxide, which causes the bubbles you see on the top of the starter. As well, the natural holes that you see in bread are produced by carbon dioxide.

Here is a photo of the starter after five days. Note the bubbles of carbon dioxide on the surface. I feed the starter every day with equal parts of water and flour (organic, unbleached is the best).

You will have a usable starter in five to ten days, and you can keep the starter going for many many years.

I prefer to put my starter in glass containers. However, you can also use a variety of containers from stainless steel bowls to ceramic or plastic containers (commercial bakeries often keep their starter in large plastic totes) — these will all work perfectly well.

It is good to put a top on the starter to prevent it from drying out. Make sure you leave plenty of room because it will grow as fermentation takes place.

It is best to keep the starter in the refrigerator after it has started to ferment.

This kind of starter, or pre-ferment, can be frozen. Just be sure you pull it out a day or two before feedings. The longer you have it out and the more often you feed it, the stronger it will become.

Throughout this process you will need to throw out some of the starter.  As you add flour and water it will continue to grow.