This is a “You can learn from my mistake” post … and maybe save yourself the cost of a yeast starter flask.
When pitching yeast from a starter, I use a rare earth magnet to hold the stir magnet to the side of the flask so it won’t fall into the fermenter. I think this is a common practice? Recently, after oxygenating a batch of wort, I pitched the yeast and, with the magnets still stuck to the side, I put the flask on the counter. A short time later, not thinking, I put the oxygen tank on the counter, just a couple inches away from the flask. The rare earth magnet was, of course, immediately pulled off the outside of the flask and onto the O2 tank. Surprisingly, it took the stir magnet along with it, pulling the stir magnet right through the glass !
Good warning to post. That is one strong magnet. The magnet I use is one designed to be placed in a cows stomach to collect bits of ingested metal in contaminated feed. Not quite as strong and vinyl coated.
I also use the same style magnet to hold router bits in place while tightening the chuck from under the router table.
Dang!! Without the pic, I might have mistakenly called BS on that one. I would have thought Pyrex could take that, and you’d just end up with the flask stuck to the side of the tank too. Live and learn.
I use an old-school, weak ferrous magnet. It’s donut-shaped, maybe 3/4 inch. I doubt it’s strong enough to do that, but better safe than sorry. Thanks for posting.
New rule: Remove the rod and magnet as soon as possible.
Wow! That’s a heckuva magnet! I just use a cheapo flashlight that resides magnetically stuck to my fridge to remove the stir bar before cold crashing. I’m always a bit nervous when I get it to the lip and grab it out so that I don’t drop it back in accidentally.
Sneezles61