Refreezing yeast

I started a frozen yeast bank and the freezer door was left open for maybe a half day and the yeast vials are no longer frozen. The tubes are still sealed and I gave them a good shake to mix up the yeast again.

Any chance these are still going to be viable if I refreeze them?

Damn that's a good question. There is so little yeast to begin with. Try to make a starter with one and see if you get any action. Always try to keep the frozen yeast in a small ice chest surrounded with ice packs. That way it stays frozen during the freezer cycle. Or in case you leave the door open again lol.

strumke said:

I started a frozen yeast bank and the freezer door was left open for maybe a half day and the yeast vials are no longer frozen. The tubes are still sealed and I gave them a good shake to mix up the yeast again.

Any chance these are still going to be viable if I refreeze them?

Click to expand...

So did you ever find out if the yeast was is viable?

Not yet, I'll plan the next brew day around one of the yeasts in the freezer and see what happens when I start stepping up. Unfortunately I don't have a microscope to count live cells so I'll just go on fermentation activity in the starter.

I'll post when I do brew, but I think it'll be at the end of the month.

Cool I would love to hear your results.

Success!

I took a vial of WLP002 out, thawed it in my hand and pitched it into ~200ml of starter wort last week. It took 2 days, but that fermented out and the whole lot went into a larger flask with another 500ml. 3 days later I cold crashed and decanted off about 300ml, and then added another 1500ml, which is spinning away nicely right now.

I don't know how the thaw/refreeze/thaw impacted overall cell counts, but I do know that I'm growing yeast and the starter beer does taste normal.

I'll report back after my brew on Wed ferments through (planning a 1.090 English barleywine)

Thanks for the info. In case I ever leave my yeast out. By mistake of course. I would hate to lose all my frozen yeast bank!!