This paper records an experiment to illustrate these fears are groundless. The Freezer To test the effect of cold on an instrument, I popped a spare flute head into the freezer compartment of our domestic refrigerator. The flute head soon frosted over with ice. I left it there for several days, then took it out, put it on the flute and started playing. I expected that I would not be able to play for long, thinking the extreme cold might make it painful.
Wood is such a good insulator however that the sensation of cold was mild and short-lived.
The next thing I expected was that severe condensation would form, but again this did not happen - condensation was not much more than normal. I didn't expect anything ghastly to happen to the head itself, and indeed it escaped unscathed. Again the hapless thermometer went in as well to check the temperature. I only left the head in there for a bit over a day, as I was interested only in testing the effect of temperature. The hot dry air in the oven would, if you left the head for much longer, dry the moisture out of the wood in the flute, emulating exposing the flute to low humidity situations.