So here is my first attempt at streaking a plate. This sample came from wild grapes soaked in a 1.020 starter. Obviously I have some form of mold contamination, is it possible to save what appears to be yeast colonies that the mold hasn’t reached yet?
Good streak-plating technique, nice job. To your question, it will be difficult. Whatever that mold is, there’s undoubtedly billions/trillions of spores that will disperse from the slightest air current. It’ll probably be game over as soon as you open the lid. You can maximize your potential for success if you don’t create any air current whatsoever as you open the lid and pluck cells. Good luck!
Thanks for the info. I’m on the fence as to whether or not to try to salvage yeast colonies from this plate or just re-same my original culture onto a new plate. I still have the original culture in a test tube.
You got this far, why not pull one of those single colonies and prop it up just to see what you get.
It looks like you have good single cell colonies in the 4th quadrant. So harvest them with your sterile innoculation loop and grow them up. You might have something there.
Charlie
Cool beans… I shall give it a try.
The mould could be simply from how you were working with your plates while you were streaking out. I’ve gotten numerous mould growths because of how I was breathing during the streaking.
However, with wild captures it’s not uncommon to see moulds growing from your initial blot. You’ve got lots of nice isolated colonies, so pull one of those onto a new plate and do your streaking again. I doubt you’d end up pulling over mould, however if you do, just keep at it and you’ll eventually get a clean plate.
Another thing you can do, is grow your plates in an anaerobic environment. Moulds typically cannot grow without air and your yeast will be fine. You can pull this off using a glass jar with a candle or using a spare keg and purging it with CO2 a few times.
I ended up grabbing a couple of colonies and propagating it in another 15ml test tube of 1.020 wort. It grew what appears to be a nice, densely packed colony of off white/tan yeast. I’m gonna plate that one and see how it grows. I’ll post pics as I go.