This is my first time using a stir plate (I bought the vortex) with my yeast starter; question is: How long should I leave the starter on the plate, and should I refrigerate it before brew day? Right now it’s been about 24 hours and it seems to be working great. In the past I’ve always made my yeast starter a few days in advance of brew day, put it in the fridge one day prior, and then decanted so that I only pitched the yeast. Any suggestions welcome, thanks.
Yes, stay with your SOP. The stir plate just keeps the yeast in suspension thus producing more yeast.
I suggest watching this 2 min video featuring a Wyeast microbiologist and draw some conclusions for yourself about starter best practices: http://www.youtube.com/watch?v=ng0Ib7n4DIA
Here is another great resource written by Jamil Zainasheff for the American Homebrewers Association: https://www.homebrewersassociation.org/ … tarter.pdf
Whether to decant is a matter of preference. IMO it’s not worth the trouble unless you’re making a huge starter, such as for a lager or very high gravity beer. An extra 700-1200ml of starter medium is not going to matter in a five gallon batch. My SOP is to prepare the starter the night before brewing and pitch the entire contents of the starter when the wort is at pitching temp (usually 20-24 hours after spinning starts).