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Comment by dreamcompiler | Hacker News Reader

Blue Apron's cold packs are ridiculous. The goop leaks onto the food, they're a nightmare to dispose of, and they're heavy; probably 75% of the weight of a BA box is the cold packs. If they used dry ice, the boxes would be much lighter weight -- saving on shipping costs -- and they would simply evaporate rather than needing to be trashed.

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It might not be feasible for them. Shippers place pretty strict limits on how much dry ice can go onto one of their planes, on account of not wanting to suffocate the air crew mid flight.

Fortunately, people have built-in biological CO2 detectors. If it is just flight crew (no passengers), they all have oxygen masks they can use if the CO2 suffuses the cabin.

Umm, surely you can see that's a little crazy?

I'm all for environmental awareness - but it's a bit like the people saying, oh, why do you not use re-usable containers for everything, or do you really need to dishwash everything?

Things like food safety, and not making your customers sick are enshrined in law - and that's a good thing.

Even at my work, they aren't allowed to re-serve/re-heat things that have been served once, due to cross-contamination.

I don't see what your reply has to do with my comment.

You're saying the CO2 risk is OK, because they have oxygen masks.

That's like saying, increasing the risk of crashing a car is OK, because we'll have airbags.

What I'm saying is (unless you're PETA), the welfare and safety of your fellow human beings will trump most other things.

There's a reason the crew already has oxygen masks.

The masks are there to survive sudden cabin decompression at high altitudes where the atmosphere is too thin to breath. There is only enough oxygen to last a few minutes.

Further reading: https://www.telegraph.co.uk/travel/travel-truths/truth-about...

>[...]do you really need to dishwash everything?

You don't! Unless you have flies and cockroaches infested kitchen, some stray bacteria left after just water-washing will be much less harmful than eating the stuck-on-surface dishsoap (which does not rinse off completely, since it's hydrophobic). I have an even worse opinion of people constantly bleaching their countertops. shudder

As an anecdote, I once had a misfortune of living with a guy who would never rinse off the dishsoap from the dishes at all, just leave them out to dry still covered in suds!

Soaps and detergents are not hydrophobic. They are part hydrophilic and part lipophilic which is how they pull lipids into the water when you wash something.

> Fortunately, people have built-in biological CO2 detectors.

They’re not that sensitive, though, and the symptoms are ambiguous.

Interesting. Didn't know this. And you're absolutely right: https://about.van.fedex.com/blog/dry-ice-shipments-in-air-tr...

The CO2 would enter the food, and make it taste like a weird kind of seltzer.

Is all the food air sealed?

CO2 doesn't really go into anything to any significant degree unless it's under pressure.

And yet it did when I had food cooled by dry ice. So what counts more, what actually happened, or the theory?

The reason is that if the item is cold (especially right above freezing) you don't need much pressure to get CO2 to dissolve.

The food was weird it was all tingly and fizzy on the tongue. Kind of like the flavor of flat seltzer.

Solubility of CO2 in water at 0C and roughly atmospheric pressure is about 0.001337 mole fraction [0]. CO2 molecules are 44/18 times heavier than water molecules, so that's about 3.3g of CO2 dissolved in a liter of water. Carbonated water is usually specified in "volumes of CO2". One mole of gas at STP has a volume of about 22.4L, so one liter of CO2 weighs about 2g. "Lightly carbonated" is usually considered about two volumes of dissolved CO2, so 4g/L, which isn't much higher than 3.3g. Assuming the packaging is sealed well enough to maintain a high percentage of CO2 within, and the temperature is low enough, it looks plausible that there would be a noticeable change in taste/mouth-feel. This is confirmed by a study I found showing average taste threshold for dissolved CO2 in water of 0.26g/L [1].

[0] http://sites.chem.colostate.edu/diverdi/all_courses/CRC%20re... [1] https://home.zhaw.ch/yere/pdf/Teil16%20-%20Expression%20of%2...

The theory supports ars. Calculate before you downvote.

One exception: fermenting liquids can become super-saturated with CO2 even if fitted with an air-lock to vent the CO2 to atmospheric pressure. This might cause a rather messy surprise if you add powdered yeast nutrient to an ongoing fermentation and give it a lot of nucleation points.

I’ve experienced this issue just a tiny bit with my delivery of dip’n’dots with dry ice, but more noticeably when putting dry ice in a cocktail.

It is really noticeable in drinks with direct exposure to all that gas and ice. Solid food in a box? I don’t have as much experience with that, so I’m not sure.

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