Step 1

Combine buttermilk, water, flour, and caraway seeds in a glass jar (or in another non-reactive container.

Step 2

Adjust the ingredients so that your starter has a thick pancake batter-like consistency. Stir vigorously.

Step 3

Lightly cover and leave in warm, undisturbed spot.  Check every day for progress.  You can also stir it.

Step 4

Depending on the environment (temperature, moisture, wild yeasts), this can take about 5-10 days.

Step 5

Your sourdough starter is ripe when it has a pleasant sour smell and is bubbly and foamy. You can also drop a bit in some water: if it floats, it's ripe, if it sinks, it needs a few more days.