There are some good things about a wine cellar for storage of piano
rolls.  The temperature of 55 degrees F. and the darkness will extend
the life of the rolls many years.  However, it is not a great option
in general.  The humidity is far too high, which is very dangerous
for the rolls.

In our library, rare paper materials are stored at 50 degrees F. (+/-
1 degree) and 38 percent humidity.  You could lower the humidity with
a dehumidifier.  However you will need to monitor those conditions
regularly and empty the dehumidifier daily or have a drain for the
water.  What would happen if you were to suddenly become incapacitated?
Is there someone who will look after this for you?

In general, attics and basements are not great storage locations
for rolls for most collectors.  There are other problems.  The storage
area needs to be at least as clean as the rest of the house, and you
need to watch for insects and possibly rodents, which are not noticed
as easily in places that you don't go that often.  For example, silver
fish like damp dark places, and they like to eat paper.

Generally, keeping the collection in a place where the temperature
and humidity remain stable and that you clean regularly is the best
protection for your collection.  The American Institute of Conservation
has some advice for collectors on how to store valuables like piano
rolls.  Use the advice for Books and/or Documents and Works of Art on
Paper:

http://www.conservation-us.org/about-conservation/caring-for-your-treasures#.V6jDlvkrJaS 
http://www.conservation-us.org/about-conservation/caring-for-your-treasures/paper#.V6lzUzXiyBM 

Jerry McBride
Stanford, Calif.

 [ Jerry is the Head of the Music Library and Archive of Recorded
 [ Sound at Stanford University.  Read about the Player Piano Project
 [ at http://library.stanford.edu/projects/player-piano-project 
 [ Welcome to MMDigest, Jerry!  -- Robbie