I've seen this claim various times on the Internet; for example at https://i.sstatic.net/X5jha.jpg

Put a small amount of water in a glass when you microwave your pizza to keep the crust from getting chewy

Does this really work? If so, could anyone explain why?

  • I have used a similar method: place a damp (not soaked) paper towel over the pizza Commented Aug 15, 2014 at 11:55
  • In my experience it works, but don't put the pizza plat on top of the cup. Leave the cup uncovered and put it in the corner of the microwave near where the perforated holes are. Put the pizza on a plate like normal in the middle of the Microwave. The water heats more normally, absorbing excesse heat that would have otherwise nuked your pizza. It will take longer to heat your pizza but when it gets to your desired temperature it will be like it just came out of the oven, or pretty close to it.
    – Ryan Mann
    Commented Nov 3, 2015 at 1:58

5 Answers 5


The only possible reason it could work is by increasing humidity in the oven cavity, and to do so in any significant amount, the water would have to be brought to a boil. Even so, there is no reason to believe that increased humidity would have any effect on the crust.

Otherwise, the only affect of the water is to provide an additional mass in the oven that will absorb the microwaves in competition with the pizza, essentially slowing down the heating process. It is conceivable that this might make it easier not to heat the pizza to the "rubbery crust" phase, but then the same effect could be achieved simply by lowering the power setting.

So no, there is no scientific basis for this belief other than the placebo affect.

Reheating pizza is one of the most challenging tasks, and there are many methods, none ideal.

  • 1
    It's not quite the same as lower power, since low power is actually just on and off, but I'm not sure I can see what that'd have to do with chewy crust... unless getting too hot even for a short time is what makes the crust chewy?
    – Cascabel
    Commented Sep 8, 2013 at 6:03
  • @Jefromi The power cycling is true, but averaged over time, the outcome is the same, and I didn't want to over complicate the answer.
    – SAJ14SAJ
    Commented Sep 8, 2013 at 7:30
  • I don't completely agree with this answer. Some water will be boiled - that's how a microwave works, even if the whole thing isn't fully boiling, and a small amount of water would reach boiling quickly. Humidifying the oven cavity does have some effect on bread crusts; steam ovens are used for baking baguettes, after all. I don't know that I disagree with the end result - odds are it doesn't have much of an effect since it's sogginess in the first place causing crust problems - but the premise of the first paragraph is largely incorrect.
    – Joe M
    Commented Sep 23, 2014 at 17:35
  • Increasing humidity (H) COULD have effect on cooking item in microwave. Increasing H means microwaves are likely to contact more H20 molecules b4 contacting food. Different frequencies of electromagnetic radiation (EM) will either be absorbed by the H20, reflected by H20 or transmitted through the H20. IF water absorbs some of EM, then this EM will not contact food. Thus, food is heated by different source than lower H case. IF same type of EM absorbed by H20, also contributes to making pizza rubbery, then it would make sense that increasing H would make pizza less rubbery. Commented Mar 2, 2016 at 21:55

I just tested 3 individual slices on the pizza setting. That setting basically just turns the heat on and off so the food heats more evenly.

I tried:

  1. A small shot glass of cool water
  2. A mug of cold water
  3. A mug of warm water

They were all the same. The only thing I noticed was that the pizza was cold where the shot glass was touching it. The #2 and #3 were done with the mug underneath the plate.

Stomach satisfied, but myth busted.

  • 1
    I love empirical research in the kitchen too, but the experimental design didn't convince me here. The question was whether water in the microwave does anything, and all three conditions included water.
    – rumtscho
    Commented Aug 15, 2014 at 5:52
  • I also had a slice that was reheated without water. I also had a couple slices that were fresh when the pizza was ordered. I also had functional mouth and fingers that could tell the difference between soggy and crispy crust. I've also had this same particular pizza on multiple occasions. I also had someone else confirm with me. Unfortunately, however, I did not repeat the experiment multiple times or use different microwaves... so, still plausible! :)
    – s g
    Commented Oct 21, 2014 at 5:02
  • 2
    @s.g. could you edit the info from your comment into your answer too? Commented Dec 16, 2014 at 16:22

I just tried it, it doesn't work. End of story.


I think the increased humidity in the microwave would help.

When baking bread, adding some steam to the oven (via steam-injected or adding some water to a hot pan beneath the bread), helps get a nice crust on the bread. I believe the theory in this case is that the water making contact with the surface of the bread allows the surface to get little hotter and cook the outside of the bread more than the inside of the bread because the water transfers heat better than the air.

I don't see why this should not apply to reheating something as well, but as @SAJ14SAJ said, the water would need to get sufficiently hot.

I have also seen when baking bread someone use a spray bottle to mist the bread with water. Perhaps this too could be done to the pizza crust.

  • I must disagree. When baking, the steam at the beginning keeps the surface softer for a while so that the bread can rise better & without tearing - especially combined with cuts on the surface to choose where the bread should expand. Misting with water after baking (just before removing from the oven) gives the bread a somewhat glossy surface.
    – Stephie
    Commented Dec 15, 2014 at 20:32
  • Yet when I had not steamed/misted my bread I got no real crust at all. Surely then the moisture is responsible for crust's crispiness at least toward the end of the baking process. I'm no expert, but I've only ever seen the steaming being cited for crust creation which is why I would think it applies to the original question.
    – Aaron
    Commented Jan 12, 2015 at 22:21

You're all wrong in fact. The microwave heats water particles. The exact reason you can cover a heating meal with a paper towel without it igniting. The glass of water is meant to alleviate the intensity of microwaves heating the pizza and crust, thus avoiding an overcooked, chewy crust. No myth needing to be busted.. Best way to solve it all, stop ordering a whole pizza for your lonely ass & share. No leftovers = no reheating

  • 3
    Some of the answers already mention this possible mechanism. That doesn't mean it actually works, though - a couple people tried it and found no benefit. Next time take the time to read what people wrote before you call them wrong.
    – Cascabel
    Commented Mar 21, 2015 at 18:53

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