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I recall reading or watching something at one point that I apparently found credible enough to bother mentally filing away that suggested that if one washes off an invisibly thin outer layer of something or other from the surface of an eggshell then one has to store it differently or something like that. Do they keep longer or for less time, or require different storage conditions if they are washed or unwashed?

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  • For the storage part of the question, see cooking.stackexchange.com/a/22723/67
    – Joe
    Sep 19 at 1:10
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    Worth noting that most eggs in some countries like the US, Japan, and Australia are sold pre-washed - washing them again won't do anything.
    – Nuclear Hoagie
    Sep 19 at 13:20
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    @NuclearHoagie : not fully true— washing the eggs can cause problems if the bloom is already gone. See cooking.stackexchange.com/q/93595/67
    – Joe
    Sep 19 at 19:41
  • If you find eggs in the fridge in the supermarket they are usually washed. E.g. in the UK chicken eggs are not found in the refrigerated section as they are not washed. Some speciality eggs (quail) sometimes are refrigerated.
    – Marianne013
    Sep 20 at 12:50

1 Answer 1

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You’re washing off what’s called ‘the bloom’ which is a protective coating that’s not entirely obvious at first glance.

Once you wash it away, the egg will degrade more quickly, so in the US you’re required to refrigerate it. (And you don’t want to leave them out of refrigeration for an extended period of time because moisture will condense in them and may carry bacteria or other problems into the egg)

Eggs last much longer with their bloom still on, and they last longer refrigerated, but countries that don’t pre-wash their eggs may not require them to be refrigerated so may have all shorter storage periods

Update: Egg bloom is a liquid secretion from the chicken that coats the outside of the shell before it leaves its body. It dries on the shell, but the coating helps to seal the contents from bacteria and reduces the amount of gas exchange and moisture loss.

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    UK regulations [unwashed eggs] say best before 4 weeks from the laid date, unrefrigerated. [This date is printed on every egg.] There is no specified storage time for refrigerated.
    – Tetsujin
    Sep 19 at 6:18
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    @Tetsujin To be clear, the UK also says the best way to store [unwashed] eggs at home is in the refrigerator.
    – Sneftel
    Sep 19 at 6:42
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    @Sneftel - indeed, but alongside that advice is that you should store them in their original box, in the centre of the fridge, not in the egg tray. The entire idea for storage in the UK is that the temperature remain as constant as possible. I can't say that's something I've ever bothered with - not that an egg has any chance of lasting until its best before date in our house anyway ;)
    – Tetsujin
    Sep 19 at 6:47
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    A short description of what "the bloom" is might help this answer?
    – Deleted
    Sep 19 at 20:11
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    Since everyone always seems to forget Canada in this discussion: Yes, the eggs are washed US-style here.
    – Karl Knechtel
    Sep 20 at 7:33

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