Why does Ice cream harden if sitting in the freezer for too long? 
Granted I had this wonderful soft praline pecan a week ago that is now
stiff and "icy", and a pain in the b*tt to serve.  Is there anything I
can do to thwart and/or reverse
this effect as well?  Thanks!

Hi there!

Ah, icy hard ice cream, the bane of ice cream lovers the world over.

I'll bet your ice cream consumption is such that you buy a half
gallon, then only eat a small scoop every once in a while (which is
why you still have ice cream in the freezer a week later).

And you probably, if you're like me, either pop that half gallon in
the microwave for a half a minute or leave it on the counter for a
little bit to soften it enough to scoop, right? And pop it right back
in the freezer when you're done?

Though we're kinder to our waistlines by not eating more than a little
bit, and it's so much easier to scoop when we've let it soften a
little, we're also making each subsequent attempt to serve the ice
cream just a little bit harder.

Why?

Thawing and refreezing.  

You probably already know that when ice cream is made, teensy-tiny ice
crystals form in the ice cream as it freezes.  This is what gives ice
cream both its name and its yummy frosty texture.  There's a nifty
scientific explanation of the structure of ice cream here - scroll
down to "Structure From Ice Crystals":

Structure of Ice Cream
http://www.foodsci.uoguelph.ca/dairyedu/icstructure.html


Unfortunately, it's also what causes problems later:

"Thawing and re-freezing ice cream allows the microscopically tiny ice
crystals in ice cream to refreeze as big crystals, making the ice
cream grainy and harder to scoop."

Guide to Home Handling
http://www.cedarcresticecream.com/handling.html

"Each partial melt turns some ice crystals in the ice cream to water.
When the ice cream refreezes, the melted water is absorbed by already
existing ice crystals, making them bigger. The result is fewer but
larger ice crystals and a gritty texture."

Sweet Freeze
http://www.findarticles.com/cf_dls/m0BFU/12_88/97329164/p2/article.jhtml?term=

Yuck.  So how to fix this?  

Cut down the number of thaws and re-freezes, either by not letting the
ice cream soften before you try to serve it or by purchasing your ice
cream in smaller quantities.  The fewer times the ice cream thaws and
refreezes, the less of a hassle it will be to serve it.

Hope this helps!

--Missy  <-- likes to make her own ice cream.

Search terms:  [ "ice crystals" "ice cream" ]

Works for me, do wish for a better solution but can't escape physics I
suppose, thanks!