Just got a stir plate and will use this for a WL500 yeast starter this weekend. Need to pitch about noon on Monday. Directions say 24 hours in advance but I am thinking 48-advice?
I generally leave on the stir plate for about 24 hrs., then cold crash for a day or two. When you’re ready to pitch, you pour off the liquid and pitch the yeast at the bottom.
I think the number 24 comes from the liquid culture phases. As far as I know it takes about 16-24 hours to get most yeast stains into mid-log or stationary phase which is ideal for pitching. I think if you crash and drop down at around 24, you may arrest them as such state and be able to pitch the same active yeast but in a smaller volume. By 48 hours you’re probably looking at second generation oh yeast in the end of stationary or in the death phase. You can still pitch that and they’ll come back and ferment and all. They just aren’t going to be as healthy and live cell count will probably be lower at pitching time. This may or may not affect the beer much though.
I put the starter on as soon as possible, usually 5-6 days before brewing, and when it’s done, and not before that, put it in the fridge overnight and decant before pitching.