After preparing your sourdough starter using either dried yeast or wild yeast, examine the color of your sourdough starter. If you notice your sourdough starter is pink, orange, or dark brown, this is an indication that the starter is contaminated and that you should toss out the batch.
While there is some lee-way for tending to your starter, neglecting your starter will cause mold to develop or result in the bad bacteria taking over the batch. Mold can manifest in various colors and is generally fuzzy in appearance.
As your sourdough starter is developing, you may notice a liquid forming on top of the starter. This liquid is referred to as “hooch”. Hooch is the alcohol given off as the wild yeast begins to ferment.