harvest from a frozen/thawed/frozen/thawed beer?

I've been looking at all the information on harvesting yeast and it got me wondering about a few bottles I rescued.

I've got five bottles of Erdinger that are nearly three years old. They were frozen for an entire Alaska winter (late sept-early april). The bottles didn't burst (I don't know how) but I was wondering if that was a red flag waste of my time or what?

They have been frozen and thawed multiple times over the past few years.
Is it worth my time?

That's my question, here's some back story: I obtained a few cases of erdinger in summer of 2009, and all but these 5 bottles were consumed throughout the next few months. I left these 5 for thanksgiving or something and forgot about them. When we bought our new house and moved i put all the racks in the shed because they were all empty, or so I thought. Fastforward to Oct 11 when I decided to start homebrewing and went to retrieve my empties to see if they were useable in my new venture. They are now thoroughly thawed and just collecting dust. I was gonna pop the tops and use the bottles but thought I'd give the whole yeast harvesting a try.

Thanks.

Probably best to harvest from new bottles or use a similar strain bud. You could harvest from these bottles and grow it up, but you'd have to start with a small starter and grow it up, though after all this time, no telling what youd end up with. Although, if they're still surviving at this point, you may own the newest Eis-capable strains.

all the 'frozen yeast bank' articles i read involved using glycerin (I believe) to help preserve the yeast.

freezing and thawing several times, without the proper preservation medium...I doubt there's any viable yeast left.

Try it... it probably won't work but if it does you know you've got some of the most badass yeast out there!

I've got nothing to lose and 5 shots at it...I'm trying to source some things locally to harvest and grow yeasties so this will definitely be a project for the coming weeks..