Ahh, it may have been the heat pasteurization that did it in. If you care to glance at a scientific paper, here’s an interesting source. https://pubs.rsc.org/en/content/articlelanding/2019/ra/c9ra01533g I want to say I’ve seen a low temp method of pasteurizing (that you have to hold for a good bit longer) but for mine I avoided heat like the plague and did everything cold with a huge starter to ensure the yeast outcompete anything and fill the fermenter with alcohol to handle any potential unwanted microbes
Live and learn right? And oooh the red yeast rice idea sounds interesting