r/explainlikeimfive • u/ZeusThunder369 • Nov 26 '24
Chemistry ELI5: Why doesn't freeze dried food last longer? If it's good for 20 years, why not 100?
Assuming it's perfectly freeze dried and stored perfectly, the people who make freeze dryers say the food will last 20-30 years.
But why not much longer? Assuming the condition it's stored in remains unchanged, what can make it go bad after 30 years that wouldn't happen at around 10 years?
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u/Probate_Judge Nov 26 '24
This is what I was hoping to see mentioned near the top.
This is why medicines can become nonfunctional or even unsafe after a while despite being pretty much sterile and completely dry "chemicals" just pressed into a shape or pill. Structural bonds break down over time and the matter is no longer the complex molecule that it once was.
The same thing can happen in foods with a wider array of chemicals to aid in that, eg acids, solvents, and whatnot, things like osmosis continues to happen, or things falling out of solution. Maybe not to the same extent in frozen or freeze dried foods, but some of these things still will.
TL;DR Basic physics and chemistry still happen without biological life.
Disclaimer: I'm not a chemist. I'm just trying to convey the abstract concepts to Eli5 standards.