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 !
In the future, I think I’ll take the magnets off the flask right after pitching and put them someplace safe.