Hi again Alex, I had a recent conversation with Debra Wink, who is a microbiologist and guest sourdough instructor At King Arthur's baking school, and it turns out she might have an explanation for the film you've noticed on the top of your starters since you moved to the Caribbean! She believes it's possible the film on top of your starters could be related to trapped heat, particularly if your starters stand in direct sunlight during part of the day. She's noticed a similar "greenhouse effect" when starters are placed under a light bulb for warmth, without temperatures being monitored. As long as your starters are performing well, it's fine to peel off the film and proceed as usual, but if you experience further issues you might want to consider finding a cooler, shadier spot for your starters to dwell. Barb

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