Frost-free freezers

Stephen C. Dahl stebby at welchlink.welch.jhu.edu
Fri Nov 20 15:18:32 EST 1998


Hello all,
I'm going to kill two birds with the proverbial single stone here...

: Philip Coffino wrote:
: > 
: > Our 18 year old freezer just died this week.  We are in the market for a
: > new NON-frost-free freezer (with attached 4 degree space) and have come
: > across the problem that most, if not all, suppliers carry frost-free
: > versions.  Does someone know of a brand or supplier who still makes
: > NON-frost-free freezers??


General Electric continues to make manual defrost freezers.  Call a dealer
and ask for availability on models FP14D, FP17D, or FP21D.  The number
denotes cubic feet.  The bigger ones come with optional locks and alarms.
We have 2 and they work fine.


Gail Otulakowski (gotulak at sickkids.on.ca) wrote:

: Actually, I would love to collect some opinions about the necessity of
: a  non-frost-free freezer for enzyme storage (Defrosting is a real pain
: in the neck).  We now store all our enzymes in insulated boxes (e.g.
: Stratacoolers) in the freezer anyway, just to minimize temp fluctuations
: when the door is open, etc.  Wouldn't this be enough protection against
: the temp changes during the defrost cycle of a frost-free freezer - or
: is there another reason for not using frost-free freezers?


Your enzymes should be fine.  The problem is that other aqueous solutions
including serum, aliquotted buffers, samples, etc, will tend to lyophilize
in a way and you'll end up with stalactites hanging from the top of the
sample vessel and and a concentrated or even dired sample in the bottom of
the tube.  For somethings this is not a crisis, but for serum you end up
with a goo residue that refuses to resolubilize.  For this reason, I do
not recommend the frost-free.

Regards,

Steve Dahl



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