osmosis

[Tweed]

When I put my vegetable broth, which is in a freezer bag, in a bowl to defrost, the bowl fills with broth flavoured water. Is this osmosis in action (along with a little condensation)?

[atalanta]

You have a hole in the bag, or an inefficient closure. Plastic bags don't do osmosis.

[gingejbee]

Yes, it's called a leak - even if it's not leek soup.

[Peter Pedant]

I think people are being alittle unfair here

I think was is happening, is the same effect as a fridge where the ice collects around the freezer/cold part.
This is connected to freeze drying
and is to do with vapour pressures being lower in lower temps (so dew or frost forms)
but you have the idea of broth flavour
and that is to do with vapour pressures of oils and fats.


if any of your frenz have kids doing Chemistry A level he will be able to explain what is quite an interesting question
and take in questions like why you cant distil water/alcohol to 100% but it seems to stick at 97% and not more
and also apple-jack where you freeze an alcohol.water mixture and thereby enrich the alco content.

I think this is a question on constant boiling point mixtures and eutectics.

[jomifl]

As atalanta said, (most)plastic bags don't do osmosis, and if they did only water would come through but only if forced at pressure.

[seadogg]

Yes, osmosis needs a semi permeable membrane I seem to remember. When I do it there always seems to be a minute amount gets on the outside of the bag which "flavours" the condensation. We just tip it into a pan to thoroughly heat up.

[Tweed]

Thanks for answers folks