I want to have boiled eggs in the morning when I wake up. For this I want to use a standard rice cooker.

My plan is to add the eggs and water before going to bed, set a timer and go sleep.

Is it possible and safe to leave the eggs and water in my rice cooker until a timer starts the cooking? Will soaking the eggs overnight change their consistency or flavor?

Note: This question asks something very similar for rice.

  • This and this questions are also related Commented Oct 21, 2017 at 17:45
  • 1
    Hello, and welcome to Stack Exchange. Where are you located? This matters, because different countries treat their eggs differently, with the result that some must be refrigerated and some don't need it. Commented Oct 21, 2017 at 22:18
  • 1
    Hello, I am living in Brazil. Here, eggs are usually kept at ambient temperature, outside the fridge. Commented Oct 22, 2017 at 15:50

2 Answers 2


Go for it. Eggs in their shell are pretty sturdy. Technically, a very small amount of water will be absorbed by the eggs, but unless you weighed them, you probably won’t notice.

I do have a small caveat, though: eggs are susceptible to smells, the chalky shell is pretty permeable. So if your tap water has a lot of chlorine or other strong tasting stuff, it’s probably not a wise idea to let the eggs absorb that. The same is true if you live in an area of the world where tap water may be contaminated by bacteria. In such a case, you need to boil the water first before adding the eggs.

In short: if the water is good, no problem.


If you absolutely can not wait to boil the eggs in the morning and prepare your breakfast like the proper ritual it really is, you have to take these in mind.

  • Eggs are electively permeable. This means some molecules, like water, can enter through their membrane and thusly inflate it which will make it possible for them to break in boiling, or even before.
  • Can you really control the way they will be cooked in the rice cooker? Sure it's okay if you want the yolk solid, but if you want it liquid you'll have a problem.
  • Perhaps some taste or smell will seep through the membrane. For example metallic taste, chlorine used to clean water or worse anything health damaging. If you pre-boil the water, leave it to cool, salt it to make the mixtures somewhat of the same concentration (where mixtures are the water and the inside of the egg) and don't care about cooking time you can have a safe go to try it. Look for weird tastes or odors.
  • If they are permeable the water should able to get in and out.
    – paparazzo
    Commented Oct 22, 2017 at 13:10
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    Yes, but not the way you think it does. It goes in if the outside mixture is of a smaller concentration than the inside one and thusly the egg inflates nad breaks, if you dilute a kg of salt in an amount of water so that the new concentration is greater than the egg's, the the egg will suck on itself. It's a procedure called osmosis that depends on mixture concentrations, you can look it up in wikipedia since it's basic enough. en.wikipedia.org/wiki/Osmosis
    – The Doctor
    Commented Oct 22, 2017 at 18:07
  • So if no salt was in the water then water would not penetrate? That is contrary to posted experiments. exploratorium.edu/cooking/eggs/activity-nakedexperiment.html Not buying. And not going to argue with you.
    – paparazzo
    Commented Oct 22, 2017 at 19:10
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    No, I am saying that if no diluted substance => egg inflates and breaks.If too much diluted substance => egg deflates and maybe breaks. Only way for no water penetration is equal concentrations. Try to focus on my words this time.
    – The Doctor
    Commented Oct 24, 2017 at 17:49

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