It's no longer a secret that sourdough bread is much more nutritious since this yeast is 100% natural! With this practical kit, it's easy to make your own sourdough at home. This starter kit contains: two glass jars and a spatula. Each jar includes a lid with a valve to vent the gases, a silicone strip that acts as a marker, and a silicone ring which you can use to track the dough as it rises.