Can you freeze a milk box?

September 23, 2012 10:45 AM

You know those aseptic packages of 1% milk? Can you freeze them so that they're merely cold by lunchtime? Or does the milk separate or the container blow up or something? Thanks!
posted by Mayor Curley to food & drink (10 answers total)

Mommy boards say yes but

- the boxes expand and become little pillows (9% says this site)
- they sometimes won't thaw by lunch

If you've got one of those subzero type freezers, I wouldn't even try this, too freezy. Otherwise I'd experiment. My experience with extensive freezing of non-boxed milk is that full fat milk that is partially thawed can be really weird because it separates a little and thaws at different rates and can be sludgey. Skim freezes and thaws pretty normally.
posted by jessamyn at 10:52 AM on September 23, 2012 [2 favorites]

In parts of Canada they sell milk in bags. They normally come in packs of six or something like that and it is completely common practice to freeze the currently-unopened bags of milk and then just pull a new bag out when the old bag is almost- or completely-empty. Does the milk no harm, so it's reasonable to expect the same of a frozen carton, except that there's no room left for expansion, so the carton will expand like Jessamyn says.
posted by urbanlenny at 10:57 AM on September 23, 2012

We do this for our daughter, but only freeze the milk the night before so that it isn't quite so rock solid, to make sure it thaws. if you have a way to speed the thawing wherever you're going, if you have a longer time, or if you don't mind if your milk is icy (maybe you put it in a cup?), you'll be fine if you store them that way, I'd think.
posted by dpx.mfx at 11:01 AM on September 23, 2012

Like any other water product, it'll expand by 9% when it freezes. Whether that bursts the package depends on the package.
posted by Chocolate Pickle at 11:17 AM on September 23, 2012

I asked because once upon a time I left a jug of whole or 2% too near the back of the fridge and it separated when it froze. Sounds like it's worth trying-- I'll bag it too, just to be safe. Thanks for the answers!
posted by Mayor Curley at 11:53 AM on September 23, 2012 [1 favorite]

You might try wrapping the bags so they don't explode. When I was a kid we used to freeze canned sodas and juices in a regular freezer over night to keep them cold for picnic lunches. Wrapping them tightly in newspaper kept the cans from exploding.
posted by oneear at 12:16 PM on September 23, 2012

Frozen then thawed milk will separate a little. Usually shaking it well will mix it all up again. I've found the taste to be the same afterwards. My teenage daughter thought there was a distinct difference in taste, but not enough to make her stop drinking it.
posted by SuperSquirrel at 12:22 PM on September 23, 2012

This is probably more info than you want, but if you know the principles involved you're likely to have better luck. Some proteinaceous solutions just don't freeze well, but if they do the critical points are during the period of freezing and thawing.

What happens is that pure water (which has a higher freezing point) freezers and thaws first leaving you with a very concentrated solution in the center of the container. When you get very high concentration of protein you are more likely to aggregate and flocculate. The rule of thumb is that faster is better on freezing and that slower is better on thawing. Ideally, you'd bring your entire block of frozen solution to just below the freezing point so that it all thawed together.

Another thing that contributes to this is the liquid air interface. I once turned a half thawed vial of drug into the snow globe from Citizen Kane with one of these. Ooops.
posted by Kid Charlemagne at 12:23 PM on September 23, 2012 [1 favorite]

Canadian with plenty of experience with milk in bags here. My Mum used to freeze extra bags of 2%, and the milk did separate slightly, but shaking it after thawing resulted in reasonably tolerable milk (I was a picky kid.) I certainly found it more drinkable than the little cartons of milk that were brought into the classroom at 10 but not consumed until about noon, when they had turned from cold to tepid, with an additional lovely flavour note of cardboard.

So give it a go. We used to freeze our cans of pop overnight, too, and they only occasionally exploded.
posted by maudlin at 1:02 PM on September 23, 2012 [1 favorite]

I buy Trader Joe's milk boxes in the US once in a while. I throw them in the freezer and pull them out in the morning. But I have to tell my kids to drink them after school, not at lunch, unless it's hot out. I have better luck if I pull it out of the freezer the night before and put it in the fridge. Or maybe freezing it late the night before would work - that's a good idea above.
posted by Chaussette and the Pussy Cats at 6:27 PM on September 23, 2012