Can I wash yeast from my primary if I started with a dry yeast?

[flars]

You certainly can harvest the yeast. The only difference is that you now have liquid yeast based on the dry yeast used. Read through this topic for more info on rinsing, or not rinsing to maximize the yeast harvested.

Can I save a yeast cake

When i’m ready to use saved slurry I’ll pour off the majority of the beer on top leaving just enough to swirl up the yeast for pouring out. After returning it to the fridge it will separate again. As long as there’s a little beer on top it’s enough to protect the yeast.