I made my first starter last night for an IPA I’m brewing this afternoon. I have a 1L beaker, boiled 1,000 ml water to 100 grams DME. Cooled it, pitched the yeast, woke up this morning and the sponge stopper was dislodged, kreusen down the side of the beaker.
Is my starter still ok? I sprayed the side of the beaker with star san, gently pushed the stopper back in.
Your starter is most likely okay. The krausen coming out kept anything floating in the air from going in.
Go with at least a two liter flask for a one liter starter. I use a 1.1 gallon Rubbermaid storage container on the stir plate for my starters. I heat and cool the starter wort in a kettle.