I have been overbuilding starters to propagate for the next batch, and have been successful with two batches starting from a single pack of L13. In both cases fermentation began within 12 hours. However this third batch has gone 48 hours with zero airlock activity. At first I assumed I had a leak, however the gravity has not changed. The only thing I could think of is a ran the starter that I pitched on this batch at ambient temp (72-75 degrees) as opposed to 65 degrees. Could this have cause the yeast to not tolerate the cold pitch and fermentation temperature (50 degrees)?