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Why Can't I Boil Water in an Oven?

The ambient temperature in the oven is higher than the boiling point of water. The water goes right into vapor due to the very low vapor pressure surrounding the water. And, as you correctly note, Mike, there is no condensing taking place so no "plume".

The "boiling" you see in a stove top is the formation of steam, captured as bubbles below the waterline (usually at the inside surface of the pan at point of release- it often follows the flame pattern below the pot).

In the case of the oven, the conduction is about the same between pan and air above it, so there is no "boiling", is what I suspect. The steam release is as much on the surface as any place else, there are no captive bubbles created below the waterline so the process is not so violent.


  • I was trying to bake some small, crusty loaves for French dip sandwiches. Have read numerous times that the secret to a good crust is high humidity in the oven--it's usually suggested to spray water into the oven at frequent intervals.

    Instead, I just though I'd have boiling water inside. Had heavy stoneware bowl in oven heated to 450F. Added boiling water. It stopped boiling immediately and never resumed. Why? Bread turned out decent, but nothing great ;)
  • Roland_16
    Roland_16 Member Posts: 6
    Water not boiling

    Hi Mike,
    I don't have a real scientific answer, just a guess. If I boil water on top of a stove, the steam jumps from the water surface into the cooler air above.
    In an oven, the vapor leaving the surface of the hot water is surrounded by ,in your case , 450*F air. I'm thinking the vapor would have a hard time condensing to visible steam at this temperature. Also, hot air can absorb lots more water than cool air so you may not ever see steam from your stoneware(or any) pan. The water is going somewhere as that pan is going to go empty at some point.

  • I understand what you mean about not being able to see the vapor (steam is invisible after all), but why no visible boiling? When I use a pressure canner I can certainly hear the water boiling inside. Even after the canner has dropped to zero pressure, when I remove the jars I still see the water boiling inside--usually for quite some time.
  • doug_44
    doug_44 Member Posts: 4
    I think part of

    the answer is that the heat is not applied directly to the container. As the water makes its phase change to vapor, it removes heat from the rest of the water and container. (Gee, sounds like a steam boiler). The hot ait surrounding the water/container is not able to transfer that heat to the water/container fast enough to overcome the loss in heat thru vaporization so the whole mess cools down to some temp below fast boil. I would think that a large pan with shallow water would work better but still may not produce a rolling boil.

  • "Pan" was a large (about 10" x 6"), shallow (about 2" deep), heavy stoneware oval roaster with about 1/2" or so of boiling water added.
  • doug_44
    doug_44 Member Posts: 4
    Well for the next experiment.

    can you try a metal pan? The local baker I have seen put regular metal shallow pans on the bottom shelf.

    I think it would help the experiment if you sent me samples of the bread from each test.
  • Water mister

    When I was just a boy........(sorry Paul Simon) I worked in a bakery. The baker would spray water from a misting bottle over the hard rolls at least three times during the baking process. All I remember is that the rolls were soft inside and crunchy as a potato chip on the outside. just my 2¢
  • Bruce_26
    Bruce_26 Member Posts: 27

    I have found that it is best to use old cast iron bake ware. Griswold brand is best followed by Wagner. What type of flour are you using. The Amish women taught me that they type of flour is all important. They do not use "All-purpose" flour. Do you have any Amish or Mennonite folk nearby? They are experts in baking. They are usually happy to show you the fine art and it is an art, of baking.

  • Thanks gentlemen. Strange that I can't find anything about this topic on the web. With everything surrounding the water (both pan and air) at about the same temperature--and both far above the boiling poin--I guess I understand why you wouldn't see active boiling.

    Next time I try to make crusty bread, think I'll put a good thermometer in the pan of water. It should be about 212F regardless of oven temp right? Would it start actively boiling (if only for a short while) if removed from the oven?

    Surely this couldn't be a case of "superheating" water as can be done in a microwave, right? That one's definitely a fact--very easy to do--if a touch dangerous, especially if you use distilled water.

  • Plumb Bob
    Plumb Bob Member Posts: 97

  • Plumb Bob
    Plumb Bob Member Posts: 97
    real reason: cooktop heats fast, oven heats slowly

    The explanations above that are in terms of even vs uneven heat are incorrect. It's true that there is more surface evaporation in an oven than on a stove, but there is evaporation at the bottom (bubbles of water vapor from the bottom) in both cases.

    The real reason is that a stovetop supplies very high heat at the bottom. A typical cooktop burner is 10,000BTU/hr going into a single pot, which is not that much less than what is produced by a boiler or furnace heating an entire house!

    In an oven, heat is carried only by convection of air. You can cook food that way, but you can't deliver heat fast enough to see water come to a rolling boil. (The oven might have a high BTU rating, but it is not being delivered directly to the water the way it is on a stovetop.) There are some small bubbles, like in soda, but they may not be easy to see, and there is no turbulence.

    The rate of water evaporation is determined not just by how hot the oven is, but also by how fast the air delivers heat to the water and also carries the vapor away. A convection oven will evaporate water much faster than a regular oven.

    The temperature of the water remains 212F even if the oven is at 500F; the heat supplied goes into latent heat of evaporation. There is no superheating because superheating is a nonequilibrium effect due to too-rapid heating, whereas in the oven the water is heated slowly and remains in equilibrium.
  • TGO_54
    TGO_54 Member Posts: 327
    Don't know why

    the water won't boil, but I suspect Brad is right.

    I do know some serious bread bakers who use ice cubes in the oven to get a larger and longer lasting steam mist in the oven.

    Just make sure the bottom of the oven is clean, or you will be steam cleaning it and adding some interesting flavors to your bread ;-)

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Maynard
    Maynard Member Posts: 74

    We have An Oven In A Bakery that Uses A Small Steam Boiler To "Inject" Steam Into The Oven.
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,253

    It is boiling. It is just not condensing to form vapor.nor is it trapping hot steam under hotwater as the oven has heated the whole tray not just the bottom of the pan. Steam is clear, Vapor is white.
    Cost is what you spend , value is what you get.

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  • joe lambert_2
    joe lambert_2 Member Posts: 61
    Great Crust

    You do need humidity to create a great bread crust. There was an excellent recipe in the NYT on how to do this at home. Mark Bittman wrote it called "no knead bread". Made it literally hundreds of times and it is amazing. You use a covered pot at high heat and the crust is amazing.
    Here is a link:
  • Bill Clinton_5
    Bill Clinton_5 Member Posts: 38
    It isn't hot enough

    Thought about this for several days and concluded the water just doesn't get hot enough to boile: That water is evaporating. It is shedding the usual 900 BTU/lb it takes to convert liquid water to vapor. It will warm to the point that the shedding of BTU exactly equals the its absorption of BTU from the surrounding oven.

    Think of your own body: You can walk outside when the temperature hits 115 degrees. It might be uncomfortable, but so long as you don't dehydrate, it will do you no harm. Your core body temperature won't get over maybe 100 degrees. Evaporation is cooling it. Same thing with the oven.

    Bill Clinton
  • World Plumber
    World Plumber Member Posts: 389

    Heat chases cold. If the air above is the exact same as the temeperature of the source heating the water. What is there to absorb it. It's like pumping refrigerant from one condenser to another condenser it's not going to vaporize. That's my theroy. We never talked about boiling water in an oven in physics class. But for gases to boil off there must be either a temperature or pressure differential. In a boler we have a temeperature differential in the oven the pressure and temeperature are the same in the pot and outside the pot.
  • World Plumber
    World Plumber Member Posts: 389
    harth baked

    Hey when I was driving and picking up from the specialty bakeries. The head baker told me to put floor tile in the oven to sit the bread on to give it the harth baked taste and texture. And of course spill some water to harden the crust just before removing the bread from the oven. Did you try putting cold water in the heated pot. That should give you some gasing off until all the temeratures equalize. BECARE OF A FLASH OFF COULD GET BURNT. That's what they said in physics class. A temeperature or pressure change is needed to boil off a gas.
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