I froze my mixed E6 chemistry at the suggestion of someone in these forums who insisted that it was the way to go. Unfortunately, it ruined the chemistry and an entire batch of film. Never again!
Did you freeze the concentrates or the mixed working solutions? If the latter, it would not have "ruined" your chems. I've been doing this for years and have never experienced a single failure or ruined roll of film. I processed 4 rolls 3 weekends ago from frozen stock and all chems thawed perfectly with no precipitates. All solutions were clear (minus the Bleach and CD of course) with no evidence of any components failing to redissolve.
As for your ruined chems, what was their physical appearance after thawing? Did they look different than freshly mixed chems? Did you process any film with that same batch before freezing? Some additional info would be appreciated.
I have found that dropping temperature extends the shelf life by reducing oxidation greatly.
However, just to be 100% sure, I wouldn't recommend going below 10 deg.C. Even this should give a very nice effect in many cases, maybe doubling the shelf life compared to room temperature storage, or better.
Personally, I store XTOL, C-41 and E6 solutions (not bleach, as it keeps perfectly at room temp) at 4 degC without any problems.
My test earlier showed that XTOL stored at 4 deg.C in a partially filled bottle with a lot of air kept as well as carefully squeezed bottle at the room temp, while a partially filled bottle at the room temp was spoiled quickly. So, I'd conduct that displacing all the air and storing at reduced temperatures would give a very long shelf life. Just don't go too low --- it may work but do it by your own risk!
So... I put a (plastic) bottle of stock Microphen in the freezer, in order to get it cool fast (from 30c to usable 20), then I forgot about it and it spent six or seven hours in the freezer. When I remembered to take it out, it was totally frozen.
...and the question is, what happens now? Can I use that Microphen again? It's only been used 5 times and it's a shame to throw it away, but I (obviously) wouldn't want to risk destroying my films.
Do not refrigerate or freeze any photographic solutions unless the manufacturer says that it is OK. I know of only one and that is Ethol TEC. The manufacturer suggests that refrigeration will increase the product life.
A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.
For example, the freezing point of glacial acetic acid is 15 degrees (high 50s in the old reckoning).
I remember seeing, a long time ago in a college lab store, a gallon glass bottle of glacial acetic acid which had shattered in a sudden cold snap over the Christmas hols, despite low heating being on.
It's not the sort of stuff that you want to find running down walls and over the floor as it unfreezes again!