My rude awaking began with this culture. Actually, I let this grow for quite some time, long past my observations. However, it confirmed what I theoretically knew; mold, bacteria, and yeast are all around. Visually confirming something you cannot observe without the use of a microscope is powerful. The carpet in the petri dish I produced can be replicated in any but the most sterile lab conditions. Really – there are no visible molds growing ANYWHERE in my house. My lab is in the basement and you cannot smell anything that resembles mold or mildew. The filter on my furnace is 5″ thick and can filter to 3μm, and is equipped with a UV lamp.
So what to do?
1. Assume everything you handle is contaminated with mold, bacteria, or wild yeast. Let your guard down and you’ll be sorry. Very sorry.
2. If you think you’ve cleaned your lab and equipment well enough, you haven’t. Read #1 again.
3. Yes, air moves. Yes, all of those bad bugs catch the wave and ride it until they reach something worth feeding on – like your wort, agar plate, and yeast culture. I read several books and blogs that suggested closing the vents or turning off the furnace / air conditioner. That is one of the best suggestions.
4. Finally, when in doubt, remember this – there is mold, bacteria, and/or wild yeast everywhere you believe is clean. “Indeed, studies of human exposure to air pollutants by EPA indicate that indoor levels of pollutants may be 2 to 5 times – and occasionally more than 100 times – higher than outdoor pollutant levels.” (EPA, 2014). You WILL have contaminated yeast cultures if you believe otherwise.
After seeing the culture, I almost gave up on being a yeast rancher. If this is what I have to look forward to, and have to deal with this every time I culture, then why even try? I did think those thoughts, for about 30 seconds. Then I remembered something – just one of my brain cells can kick any bug’s ass, blindfolded.
Besides, I love the smell of fermentation in the morning – it smells like victory.
MI Beer Snob 