. when judging wine I frequently see a light bubble on the edge of the test glass. After talking it over with a judging team we usually note it but ignore it on the score. If at home I will put 100 ml in a gravity cylinder and pull a10 inch Hg vacuum on a wine. It is not unusual to get bubbles, ,,, your wine will fall in the normal if it still has CO
2.. A 5 inch Hg vacuum is available if you own a home vacuum cleaner, I encourage you to try the vacuum test the next time you think you are completely de gassed (use a single hole cork and tubing to seal cylinder to vacuum), my bet is gas will come out. With a vacuum corking set up I see it on wine I thought was a year old and of course degassed.
. natural, ambient pressure degassing is related to temperature, I will guess that your basement is cooler than the previous winery, ,,, ie it has a greater tendency to hang onto dissolved gas now. If you are serving at the warmer temperature it will want to come out of solution.
. normal wine is at a pH below 4.0, most bacterial families will not grow in this range, we work to maintain a no oxygen reductive environment, most bacteria require a oxidative environment to grow, ,,, ie if you have a good air lock the infection risk was low. Also note the risk of food poisoning is basically zero under conditions creating quality wine.
. if you get SO
2 up to 100 ppm the taste will be obvious, try mixing a few grains of meta in a sample and taste it, ,,, my guess is the flavor is quite different and you will decide high SO
2 is a defect that creates what judges call a major defect
I did a lengthy degassing with a wine whip and tested until I was certain gas was finished. I'm convinced it's a bacteria issue in part because I did everything in the basement for the first time.
For me the conclusion has been light CO
2 doesn’t matter.