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With a boiling pot of water with lid on, can I get different steam temperature? This is without the use of a pressure cooker.

I understand the phase change process of water to steam and that steam contains higher energy than boiling water. But is the steam maxed at 100 deg C by boiling a household-pot of water and a lid? Or can I increase the steam's temperature further by applying more heat on the pot? Or will that just increase the production rate of steam?

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The heat of steam is limited by the amount of pressure you can build. If you want much hotter steam, you will need some pressured vessel. Having said this a tight-fitting lid will increase the pressure somewhat. We know this increases the pressure as sometimes with a tight light you might have the lid bounce up off the pot. This is due to the pressure overcoming the weight of the lid. This happens even if the lid has a steam vent. Only so much pressure can be released through the steam vent.

Having said all that if I don't think this will be very useful but of course this depends on what you are trying to do.

To answer your question the question you posed in the comments: "So once i have an open pot of boiling water and I then increase the flame, what changes? Is it the steam production rate or am I just wasting energy/gas?" You are almost certainly wasting energy/gas. In almost all circumstances, more steam will be produced as you try to add more heat to the water. This will increase the rate of production of the steam, but unless you have a way to trap the steam and build pressure all you are doing is building up a diffuse cloud of water vapour across all of your kitchen.

If you tell us what is your use case perhaps we could help more?

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    Thanks for the insight. I went down this rabbit hole because I have been told that some items are better steamed with a more 'powerful' steam. That nebulous comment made me think it is either higher temperature steam, or more steam. – Martin Jul 25 at 14:12
  • How to think about this is, the more pressure the higher the temperature, the faster thinks will cook. The only way to get more pressure is to trap more steam than you let escape. If you have a pot with a tight lid and a small steam hole, you can build a small pressure because a smaller amount of steam leaves the vent than is created. But I wouldn't worry about this too much. – Mark Murray Jul 25 at 14:27
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No, it is impossible. There is a physics law which tells you how the temperature and pressure of a gas are related. If you try to heat a gas up, its pressure also increases automatically. If the gas is enclosed in a hermetically closed system (like a pressure cooker) then the pressure of the system becomes higher. That's actually how (and why) pressure cookers came into widespread use - not because people wanted higher pressure, but because they wanted higher steam temperature.

In a pot with the lid, the momentarily increased pressure lifts the lid of the pot, some steam escapes, and the pressure (and temperature) fall back, until a little bit more of pressure is built, the lid is lifted again, and so on, until something changes (you turn off the stove, or the water in the pot is spent). This process is frequently observed in kitchens - experienced cooks know they have to rush to a rattling pot and reduce the stove setting before something happens.

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  • So once i have an open pot of boiling water and I then increase the flame, what changes? Is it the steam production rate or am I just wasting energy/gas? – Martin Jul 25 at 10:38
  • @Martin I can't tell you what will happen to the production rate of steam - it can get faster, or slower, or stay the same, depending on which of many competing effects gets to dominate the process. There are probably studies on this, but I haven't encountered them. Here is an article relevant to cooks: seriouseats.com/2010/08/…. If you read it to the end, you will find a description of a scenario (not yours!) where the higher temperature leads to significantly slower evaporation. – rumtscho Jul 25 at 10:44
  • Thanks for the link and the insight – Martin Jul 25 at 14:13

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