I had some wine leftover and wanted to put them in the freezer to use it at a later point for baking or cooking. So I just poured it into a freezer bag.

Today, I noticed that the bag is not frozen solid (that's expected because of the lower melting point of alcohol), but unfortunately also leaking. But not really leaking wine - more like a reddish water?

So I took it out and filled the wine into a hard plastic box container. Afterwards I inspected the bag: it has no holes. I filled it with water and there was no leaking.

What's going on here? Are freezer bags not safe to store alcohol in? The bag is made from polyethylene (PE).

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    If your freezer is cold enough your wine will freeze into a solid block. Often people use ice cube trays to freeze wine for cooking and then put them in a bag. You may want to adjust your freezer temperature. Generally a home use freezer will be zero degrees farenheit. Apr 19, 2023 at 13:51
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    That's roughly minus 18 Celsius for the rest of the world. Apr 19, 2023 at 14:06
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    @SteveChambers many whites freeze in mine, most (slightly stronger) reds don't fully even at about -20°C. That's because as ice crystals form, the remaining liquid becomes more and more alcoholic. The resulting slush can still flow through an imperfect seal. The expansion of watery liquids on freezing can also pop seals
    – Chris H
    Apr 19, 2023 at 15:24

1 Answer 1


Plastic bags are permeable to certain molecules. For example, iodine (and iirc glucose) can pass through a regular Ziploc bag. I've noticed that greasy things put in a plastic bag can cause the outside to become greasy, even when there are no leaks.

From what I've seen, alcohol shouldn't be able to fit through a PE bag. However, there is another exit from a Ziploc bag: the seal. Even if water can't get through the seal, alcohol, having different chemical properties than water, may be able to do so. That is a possible way that it got out.

Additionally, Cooks Illustrated at one point tried to use plastic wrap to remove the TCA from corked wine, and they concluded that it removed much of the taste as well, so be careful which plastics you use for storing wine specifically.

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    An ethanol molecule (C2H6O) is several times larger than a water molecule (H2O), not smaller. Apr 19, 2023 at 14:34
  • @NuclearHoagie I had to look this up, because it appears I had previously gotten some wrong information. The atoms present does not definitively determine the size of a molecule, since they could be bonded differently. However it appears that alcohol molecules are in fact about double the diameter of water molecules. I'm not sure why so many "sciency" places say that alcohol is smaller than water and can fit between water molecules, etc, but I did fix that in the answer.
    – Esther
    Apr 19, 2023 at 14:44
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    Another possibility might be that prolonged context with alcohol, which is a good solvent, weakens the plastic in some way that makes it more permeable.
    – dbmag9
    Apr 19, 2023 at 20:31

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