On agitating the brew...?

I'm curious, mostly worried haha, but is it alright, a good, or bad idea to continue to agitate the brew during primary fermentation?

It's a bad idea. You want to avoid oxidation once fermentation starts. After fermentation is winding down, you want the suspended proteins to fall and agitating the fermenter will work agaist both of those goals.

The only way I could see doing it is if you were using a highly flocculant yeast, and the yeast flocculated out before fermentation was finished. Perhaps a gentle swirl could encourage the yeast to finish up. I've never needed to do that, though, in nearly 300 batches of beer.

Got it. Well time to fess up then. It's day four of fermentation and I agitated it a bit yesterday. A little more than a "light" swirl but about that. What's the damage likely to be if I leave well enough alone from here on out?

If the airlock was in place and functioning and you "agitated" the beer a bit during active fermentation, you are fine.

If you are taking off the airlock and agititating the beer then bad things can happen exactly like Yooper said. The only way to tell is to taste the beer when you are done.

My guess is that you will be O.K. Pez.

Whew! Nope, left the airlock on. So what is the risk, in any, of oxidation/contamination when I take samples to check the SG?

Upship said:

Whew! Nope, left the airlock on. So what is the risk, in any, of oxidation/contamination when I take samples to check the SG?

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Very little. Just be carefull not to splash the beer around much, be diligent with cleaning and sanitizing, and drink your sample instead of returning it to primary.

Make sure you wait two or three weeks before trying to take a FG. No reason to take sample after sample after sample.

I don't even try an FG untill all signs of active fermentation have passed, the krausen has fallen back into the beer, and at least three weeks have gone by.
Pez.

Funny, I was just going to post about this topic today. I do this from time to time. I give the primary a few "swirls" but never splash the beer. I find it results in a bit of air lock action for about 24 hours. I was also wondering others opinions; however, I've yet to experience any down side to doing this activity.

from my experience the airlock activity is from embedded CO2 rising up from the trub/yeast - i wouldn't worry about oxidation as its covered in CO2 presumably, but why bother to swirl it unless you had to? that being said, i do kick my beers on occasion. mostly out of frustration that they're not in a bottle yet.