What do they do to soft ice cream to make it stay soft?
IANAICM (I am not an ice cream man), but I believe your answer is three-fold: lots of air (added by lots of mixing), keeping it moving (again, always mixing), and keeping it at temperatures above that which “hard” ice-cream is kept.
Air is the key factor. The more air that is beat into the mix during the freezing, the softer the resulting ice cream will be.
If they use enough Guar gum, Locust bean gum, modified food starch etc. etc. it is possible to make an “ice cream type food product” that will retain it’s shape and fluffy consistency even at room temperature. It tastes a bit funny though, and doesn’t melt in your mouth.
It’s not what they add, it’s what they don’t: hard ice cream contains Viagra.
[sub]sorry, I know I shouldn’t, just can’t help myself sometimes[/sub]
I had presumed that “soft serve” was the ice cream equivalent of Velveeta- an artificial concoction that didn’t necessarily contain any dairy products at all.