Puffy Salmon

[snoozeofreason]

I have a bag of salmon fillets in the freezer, that seems to have inflated rather since I put it in. If it was chicken, and in the fridge rather than the freezer, I'd just assume it had gone off and chuck it, but I'm not sure about this one. It has been kept at below -14C since it arrived (I have two freezer thermometers, and one is connected to an alarm that goes off if the temperature exceeds -14C). Each salmon fillet is wrapped in its own tight-fitting plastic covering, and those coverings show no sign of inflation.

I am wondering if the bag has got the "bends". In other words that whatever gas it is packed in gets absorbed somehow when it is backed, and has gradually outgassed in the freezer. Any ideas?

[dyqik]

What's the barometric pressure where you are?

It's likely packed in dry nitrogen gas, which has expanded a bit since being blown into a bag with flash deep frozen fish (probably frozen in liquid nitrogen, which would seriously reduce the volume of gas blown in). But that wouldn't explain why it puffed since you put it in. Nitrogen coming out of the fish would though, so the bends is possible.

[basementer]

What's the barometric pressure where you are?

It's likely packed in dry nitrogen gas, which has expanded a bit since being blown into a bag with flash deep frozen fish (probably frozen in liquid nitrogen, which would seriously reduce the volume of gas blown in). But that wouldn't explain why it puffed since you put it in. Nitrogen coming out of the fish would though, so the bends is possible.

But Snooze says that Each salmon fillet is wrapped in its own tight-fitting plastic covering, and those coverings show no sign of inflation. Doesn't seem to fit with the idea of gas coming out of the fillets.

[Gfamily]

What's the barometric pressure where you are?

It's likely packed in dry nitrogen gas, which has expanded a bit since being blown into a bag with flash deep frozen fish (probably frozen in liquid nitrogen, which would seriously reduce the volume of gas blown in). But that wouldn't explain why it puffed since you put it in. Nitrogen coming out of the fish would though, so the bends is possible.

But Snooze says that Each salmon fillet is wrapped in its own tight-fitting plastic covering, and those coverings show no sign of inflation. Doesn't seem to fit with the idea of gas coming out of the fillets.

They may be tight fitting, but are they airtight?

[snoozeofreason]

What's the barometric pressure where you are?

It's likely packed in dry nitrogen gas, which has expanded a bit since being blown into a bag with flash deep frozen fish (probably frozen in liquid nitrogen, which would seriously reduce the volume of gas blown in). But that wouldn't explain why it puffed since you put it in. Nitrogen coming out of the fish would though, so the bends is possible.

But Snooze says that Each salmon fillet is wrapped in its own tight-fitting plastic covering, and those coverings show no sign of inflation. Doesn't seem to fit with the idea of gas coming out of the fillets.

They may be tight fitting, but are they airtight?

I am now wondering what the purpose of those coverings is. They are reasonably strong and very tight. Maybe they are meant to stop Nitrogen outgassing from the salmon and inflating the outer pack. If that were the case then a small hole in one of the coverings might explain why my pack is slowly puffing up.

As for the barometric pressure, we live on top of a hill and my ears sometimes pop a little when we drive down into town, so it must be somewhat lower than sea-level value. But it's a hill, not a mountain. And, as you say, barometric pressure wouldn't explain why it has puffed up since it went in the freezer (I don't think it was puffy when I put it in).