I know that fermenting at very warm temperatures can cause yeast to throw phenols. The room I use for fermentation has been sitting at 64°F with ferm temps going no higher than 68°F yet I'm getting a very distinct plastic taste and smell from some of my beers. I'm currently fermenting some beers that I've added Potassium metabasulfite to drop out Chlorine/Chloramine to see if that's the culprit. What I'd like to know is under-oxygenating my wort causing the yeast to stress and throw phenols. None of my beers are over 1.050 SG and I typically splash the wort around a few moments to aerate it.