Why is ice cream always so soft when you first open the container and gets so hard over time with the lid closed in the freezer?

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Why is ice cream always so soft when you first open the container and gets so hard over time with the lid closed in the freezer?

In: Chemistry

It’s so soft because you just brought it home and it’s been out of the freezer since the grocery store. Frozen things tend to get hard over time. I dunno, but it seems like a no brainer to me.

Ice cream is flash frozen which prevents ice crystals from forming and keeps it soft and smooth.

When you open the container the ice cream melts a little then refreezes slowly. Water in the icecream and surrounding air crystallizes making the ice cream hard and icey.

Ice cream is made up of little frozen crystals. Think of them like grains of sand. Now, when you scoop up a shovel full of sand, it’s easy, but then when you take out the ice cream and put it back in, those grains melt a little and then re-freeze into something like pebbles. A little harder to scoop. Repeat the process, gravel. Repeat the process, big rocks. Repeat the process, eventually you’ve just got one big rock, or, chunk of frozen ice/fat. Very hard to scoop.

Also, frost free freezers go through cycles of slight thaw/refreeze to prevent ice buildup. I’ve found it depends on what part of the cycle I open it.

Has anyone here eaten handmade ice cream from one of those salt water ice cream makers? Is it as soft as other ice creams?

I ask because I think ice cream is whipped as it’s frozen as well, or at least whipped and then flash frozen.

The whipping might explain the softness of store fresh ice cream, and the subsequent slight melting and refreezing maybe explains the hardness.

EDIT: freshly fallen snow and ice might be a good analog to what’s going on with ice cream.