Adapted from Richard Miscovich's From the Wood-Fired Oven: New and Traditional Techniques for Cooking and Baking with Fire
Liquid levain (starter), stiff starter or rye sourdough starter:
A liquid levain refers to a starter that is maintained at 100 to 125% hydration whereas a stiff starter is maintained at 50 to 60% hydration. A rye starter or culture is made and fed completely with rye flour at 100% hydration. The liquid levain could have rye flour in it, but it is typically made with a good portion of white flour.
Sprouting the rye berries:
In the afternoon, rinse and drain the rye berries several times, then cover them with water and let them sit, covered with a cloth, at room temperature for 3-5 hours.
Rinse the berries again, and let them drain. Cover and let them sit at room temperature.
In the evening, rinse the berries again and let them drain in a colander overnight. You should see tiny shoots starting to appear, but if not, let them sit a little longer, or as long as they are soft and pliable, go ahead and use them in the soaker.