I made a starter yesterday with plans to pitch tomorrow, but am now unable to brew this weekend. I read up and sounds like I can keep the starter in the fridge for a week. Just curious how most people store their starters in the fridge? I have a 2 L Erlenmeyer Flask, covered with sanitized foil and a tight rubber band. Guessing I should have picked up a stopper with the flask? Think it will be ok for a week with the foil, or should I transfer to a jar with a tight fitting lid?