It's just a play on words. In northern climes, they've learned to make wine from grapes that have frozen on the vine. You harvest them in sub-freezing weather.
The grapes, which are functionally raisins, are especially sweet, and make a remarkable wine.
It's called "Ice Wine".
I can do it.
And sounds like the Winnie-the-Pooh version of the Asimov story "I Robot."