Fermentation increase after drawing sample

Great Forum. Glad to be part of it.
I brewed my 5 gals American Wheat (A Beer Nut Kit) on 12-28. I pitched the White Labs liquid yeast at 70 F. There was slow activity in the airlock but seemed steady for about 3 days, then subsided to none. The temperature has remained somewhat steady at about 72-74F. On 1-03 (6 days later) I drew a sample to test SG. I drew the wort through the airlock hole in the fermenter to avoid contamination and of course i used a sanitized (single step) tube to collect the sample.
The OG was 1.047 this sample measured 1.026.
About 4 hours later I noticed the CO2 output had increased substantially. The airlock was buzzing with activity and has remained steady for the past 24 hours.
I've brewed about 15 batches total over the years and have never seen activity like this. Usually, the fermentation has run it's course in a week or so.
So what's the reason? Was it the agitation of the bucket as I handled it? Did I introduce more oxygen with the sanitizer? I'm sure this isn't unusual to most but it sure is to me. I'm just trying to understand.
Thanks
Hammerd

i would chalk it up to the agitation... as for the six day slow go i havent a clue... perhapes you yeast were just being quiet, fermenting with out making a large ammount of CO2... granted this is a flawed state because the ammount of CO2 is a constant reguardless, its a ghost in the machience term, which normally means that alot of the CO2 is staying in solution rather then gasing out... technically it doesnt happen, but i have had some batches which look completely doen adn dormant and are actully fermenting great guns which actully the best way to tell is to give the fermenter a good shake, and being in primary it wont hurt it none, sounds like what happend... cheers

This is the strangest fermentation cycle I've ever seen. Since my last post (6 days ago), I left town only to return home today to find my airlock still going at it. Last week it was a bubble every 10 or 15 seconds. Today it's every 60 seconds. I'm amazed that the fermentation has taken this long to finish. My SG reading today is 1.016 so I think it's getting close. I'll check again in a couple days to see if it's ready to bottle. I think I'll name this batch "Strange Brew"

It could be temperature fluctuations, i've had brews take off after a rise in ambient air temps.

Please do not rely on the bubbles. Temperature fluctuation, agitation or just plain touching your fermenter con start a bubble of c02 to release. Trust your hydrometer. Take a reading on monday and see if it is the same as today's. If it is, then take another on Wednesday to see if it is the same. It's done if all are the same. I'm guessing it's probably done, but, the hydrometer is the only true judge.

This has happend to me, I pitched the yeast, next day nothing, take the lid off and give it some O2 and away she goes. Wine has done that to me also.

But to be honest I think your lid was not all the way down, since your gravity was 1.026 It had been fermenting and and I dont think it just stuck with the OG at 1.047. I think somehow, some way the lid was not sealed good, or pressure was getting out someplace else. between the airlock and the stopper possibly. I would almost bet on it. You mentioned your activity was slow, it may have been fast, just loosing co2 pressure someplace else, then when the fermentation slowed it took the path of least resistance.
Good luck

If you have a valve on your bucket once your done, empty the bucket put an airlock on it and blow slightly or put your finger over the airlock hole and blow on it see if there is any leaks.