I make a vegan buttercream icing with Crisco, powdered sugar, vanilla extract, and soy milk/nut milk/water. If I skip the soy milk/nut milk and use water for the liquid, is the icing totally shelf stable, considering that all of the individual ingredients are shelf stable for months-years?

[EDIT] Ok, it is not shelf stable. How can I find out how long it can be left out at room temperature? I have seen people online saying anywhere from 2 days to 2 weeks.

  • Do you have a basement you could store it in? Using water would definitely help. How about getting some ice cubes and a cooler? May 20, 2022 at 19:20
  • Thanks for the ideas @aparente001! I could technically fit it in the fridge if needed. I'm just trying to figure out how long it can be left out at room temp.
    – kayk
    May 20, 2022 at 20:04

1 Answer 1


No, it is not shelf stable, with neither water nor milk.

considering that all of the individual ingredients are shelf stable

Food safety doesn't work that way. It is not each ingredient separately that goes bad, it is the whole product, regradless of what went into it. And the mixture you describe has no good reason to be shelf stable. See also https://cooking.stackexchange.com/tags/food-safety/info.

  • 2
    A few sites I've seen seem to say it would be OK out of the fridge for 2 weeks or so, but I'm still looking for a better/more reliable source for that. That's what I would have assumed if I had to guess, as well.
    – Esther
    May 18, 2022 at 15:21
  • Your 2nd paragraph is right, but many icings are shelf stable so it's not as clear-cut as you imply. That's because they're mostly sugar, very little water and that not available for bad things to grow. Buttercream (non-vegan) isn't one of the more stable ones, but still keeps better than the ingredients at room temp according to many sources, which quote 2-3 days. Royal and fondant icings are routinely kept for weeks (Christmas cakes) to years (wedding cakes) for comparison
    – Chris H
    May 18, 2022 at 15:52
  • How do I find an official answer for how long it can stay at room temp for?
    – kayk
    May 18, 2022 at 16:14
  • 1
    @ChrisH I would consider foods like dried royal icing to "have a good reason to be shelf stable" as per the second paragraph :) Indeed, there are some cases where the mixture happens to have the same shelf life as the components, but my point was that this is the exception, not the rule, and that the icing described above wouldn't fall under that exception.
    – rumtscho
    May 18, 2022 at 17:18
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    Real buttercream is widely listed as being OK in the danger zone for days (maybe there's an official standard for an official recipe, or more likely something properly tested) so it's a more interesting problem than it initially seems.
    – Chris H
    May 18, 2022 at 20:15

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