Repitch?

[thinkfreeer]

I've got a new batch of all grain which was expected to have 1.057 OG and actually had 1.054. I harvested yeast from some commercial beer which was live. The yeast seemed to have worked out OK, but after 4 days, it stopped bubbling. I checked the gravity and it's 1.022. I was expecting lower. Should I pitch more yeast?

 

[chessking]

Its still working. Leave it alone for a couple of weeks. The fact that you have ferment activity shows your yeast is working, and after four days it is normal for the majority of visual activity to slow down, but the yeast won't be finished for a couple more weeks. Patience.

 

[sbaclimber]

Its still working. Leave it alone for a couple of weeks.

I agree with the 2nd sentence. It will prove whether or not the first one is true.
Assuming you made a good starter with the harvested yeast, you should be fine. Depending on the yeast, from 54 to 22 in 4 days sounds normal.
A couple of my earliest brewing attempts ended up getting stuck around 20-30, but that was because I was using dry yeast...I didn't make a proper starter.