Yeast starter working in the fridge?

[wisconsinitebrewer]

Evening everybody. Was hoping that I could get some help from this great site and the people on it!
On Monday, I made a yeast starter with Wyeast 1332-Northerwest ale. Things went good/normal. By Tuesday, no visible signs of fermentation. By Wednesday, there was some signs, but small. So this morning I figured that I would put it in the fridge to drop everything and take a gravity reading.
Got home tonight, pulled the starter out and found more signs of fermentation (?)
Just wanted to get your opinions/thoughts. Do I go ahead and use the starter? Chance that it might be infected? Got me stumped on this one...

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[cswis86]

Sounds like you put it in the fridge while it was actively fermenting. Probably just CO2 coming out of solution. You should really wait for your starter to finish fermenting before cold crashing.

 

[wisconsinitebrewer]

That was one of the things I was thinking. I've always gave it two days to ferment and cold crashed afterwards. Just never had seen this one before. Appreciate the insight, thanks cswis!