I am going to rack a red to the keg today and brew another 5 gal batch. Can I just re-pitch on to the yeast cake since it is the same beer, or do I need to make a starter?
Must have been a dumb question huh? I was just being lazy. I went ahead and washed the yeast and made a starter from some I had sleeping in the fridge.
I often will save the yeast from a completed batch in a large sanitized Ball jar and pitch it in another batch within a couple weeks.
The yeast in a fresh cake are healthy and ready to go. Many pitch straight onto fresh cakes and make fine beer.
However, a whole cake is over-pitching. Just using a quarter of the cake is closer to recommended pitch count.
No starter needed.