mikep wrote:I seem to remember an episode of Good Eats where it was claimed that freezing strawberries in a typical freezer was problematic because the ice crystals are formed fairly slowly, so they grow large and damage the cell walls. Alton Brown claimed that if you performed a quick freeze on strawberries by close contact with crushed dry ice, the ice crystals that form inside the berry are smaller, so they are less damaged by the time you thaw them.
That's mildly true, but essentially nothing beats getting a strawberry variety that freezes well. Some look like the day you froze them when you thaw them up a year or two later... I think it has to do with the water content inside the strawberry. Some (like the variety my family grow) are really squishy and delicious when fresh, but after freezing the only thing you can use them for is impromptu jam (add a lot of sugar to the berries, heat in microwave). Other varieties aren't very good when fresh compared to the above variety, but they hold up to freezing like it's nothing. These berries are typically quite dry when fresh, which is why they don't turn into a squishy mash when you thaw them (since the water content is so low the expanding ice crystals don't break the cell structure).
If you apply this to greens, I wouldn't freeze them since if the cell walls are already broken it might interfere with the roasting (and it probably does since one of the cracks is when the water inside the cells breaks the walls, if I remember correctly). What I would do is to store them in burlap or cotton bags as close to zero degrees centigrade as possible in a controlled environment.
