Sourdough Starter Ingredients Organic whole rye flour Raw honey Filtered or spring water (so bacteria-killing chlorine is removed) Mix 3 tablespoons (30 grams) lukewarm water (about 80˚ to 90˚F) with 1 teaspoon raw honey. Add 3 tablespoons (20 grams) rye flour and let this sit in a covered container for 1 to 2 days. The amount of time depends on the ambient temperature. If your kitchen is cool, the organisms will be less active and you’ll need more time. Ideally keep it at around 75˚F (24˚C). An oven with the light or pilot light on works well. If you can maintain an ambient temperature of 75˚F (24˚C), this first phase will probably take a day, which would be the case on your kitchen counter in the summer. If you simply ferment it in a cold kitchen in winter, it will likely take two days. When you pass by the starter, give it a mix with a spoon every now and again: your animals like oxygen in the initial stages. If they are happy, you will begin to see tiny bubbles forming on the surface of the starter as the organisms belch out carbon dioxide. This should occur after 1 or 2 days. At this point, add 3 tablespoons of rye flour, 3 tablespoons of water around 75˚F (24˚C), and 1 teaspoon of honey. Let it sit for 24 hours. Stir occasionally. Discard half the starter. Add 3 tablespoons of rye, 3 tablespoons of water, and 1 teaspoon of honey. Repeat this last step every 24 hours until the starter is bubbly and begins to rise noticeably. Once that happens, usually by day 5 or 6, you can stop adding the honey. The starter might weaken at that point (you’ve removed its sugar fix, after all), but proceed anyway. It will come alive again. When the mixture doubles in volume within 12 hours, you can think about making bread. Here’s the test to see if the starter is ready, after it has risen: carefully remove a bit of it (a tablespoon will do) and place it in a bowl of warm water. If it floats to the surface within a couple of minutes, you’ve got an active starter. If it sinks like a stone and remains under water, let the starter mature for another hour and try again. This whole process might take a week or more, especially in the winter. With my kitchen hovering around 65˚F (18˚C), it took me two weeks to achieve a predictable starter, with feedings every one to two days. Once the starter is bubbly and active, you can switch to whole wheat, or a mixture of equal parts white and whole wheat flour, in place of the rye. You can also increase the volume by using, say, 20 grams of the mature starter and then feeding it with 100 grams flour and 100 grams water.