Pot of Water on the Stove

Lisa
And much more is in most water but still invisible with eyes and can be worst than all you see in the bottom of the bowl. What you see in your water is the beginning of a long research concerning what you and your family drink,use to cook,bath...The Brita can helps buttttttt it all depends on what you want for drinking... Remember one thing: before you saw you didn't know .
nortcan

stonyloam wrote: If filled with water the pot will not exceed the boiling point of water (212°). The heat absorbed by pot will be used to evaporate the water. What you are doing is trading a little heat for higher relative humidity. You don't get something for nothing, but you probably won't even notice the difference in the stoves heat output, more a mater of being technically correct in the answer than a practical concern.

Well, true in theory but in my big cast iron pot as the water evaporates the pot temperature rises dramatically past 212° due to the very hot steam swirling around the top of the pot. It becomes too hot to handle safely and is therefore filled in place. As for energy, it takes 1000 BTU to bring a gallon of water from room temperature to boiling so you would never notice this amount of energy sucked by the water in terms of stove output. What is gained in comfort, however, for those 1000 BTUs is huge. BTW a pan of water (large surface area) placed anywhere in the warm, dry room, especially near the stove, will readily evaporate.

I have two pots on the stove to boil off water and I can go through 4 gallons in 24 hours in the cold spells since the stove is burning hotter then. If it is wash day, the laundry hanging in the basement really adds to the moisture and the "wash smell" goes through the house as well. Hard to describe it, I guess it is just the detergent smell but I really like the smell of the house on those days.

lobsterman wrote:

stonyloam wrote: If filled with water the pot will not exceed the boiling point of water (212°). The heat absorbed by pot will be used to evaporate the water. What you are doing is trading a little heat for higher relative humidity. You don't get something for nothing, but you probably won't even notice the difference in the stoves heat output, more a mater of being technically correct in the answer than a practical concern.

Well, true in theory but in my big cast iron pot as the water evaporates the pot temperature rises dramatically past 212° due to the very hot steam swirling around the top of the pot. It becomes too hot to handle safely and is therefore filled in place. As for energy, it takes 1000 BTU to bring a gallon of water from room temperature to boiling so you would never notice this amount of energy sucked by the water in terms of stove output. What is gained in comfort, however, for those 1000 BTUs is huge. BTW a pan of water (large surface area) placed anywhere in the warm, dry room, especially near the stove, will readily evaporate.

Hate to argue, but that is not quite true. Under normal conditions (sea level), with the pot open to the atmosphere the steam will never exceed 212°F, here is why: Assuming 1 gal is about 8 pounds, you are correct that it will require about 1136 BTU (of HEAT) to raise the TEMPERATURE from 70°F to 212°F (1BTU/lb/°F), however it will take another 7760 BTU to vaporize (boil) that gallon of water AT 212°F (970 BTU/lb). So while you are adding HEAT to the pot it is all consumed by the process of converting the water to water vapor (steam) and the TEMPERATURE remains a constant 212°F. So both the water and steam are are at the same TEMPERATURE (212°F) the steam contains more HEAT energy. Once it is a gas the temperature of the gas will continue to rise with added heat input (eg. convection from the stove). That water vapor will remain a gas until it looses the retained heat and condenses back into liquid water, like on your window. What we are talking about is heat of vaporization, the amount of heated need to vaporize (tear apart if you will) a liquid and turn it into a gas at a given temperature. While we are at it, the temperature (boiling point) varies with pressure, the higher the pressure, the higher the Boiling point. That is why it takes longer to boil an egg at high altitude, and how a pressure cooker can achieve higher temperatures than an open pot. Even the water in the unheated pans requires the same about of heat to evaporate, just more slowly at a lower temperature. Anyway, I wouldn't,t be carrying that pot around either LOL

stonyloam wrote:

lobsterman wrote: Well, true in theory but in my big cast iron pot as the water evaporates the pot temperature rises dramatically past 212° due to the very hot steam swirling around the top of the pot. It becomes too hot to handle safely and is therefore filled in place. As for energy, it takes 1000 BTU to bring a gallon of water from room temperature to boiling so you would never notice this amount of energy sucked by the water in terms of stove output. What is gained in comfort, however, for those 1000 BTUs is huge. BTW a pan of water (large surface area) placed anywhere in the warm, dry room, especially near the stove, will readily evaporate.

Hate to argue, but that is not quite true. Under normal conditions (sea level), with the pot open to the atmosphere the steam will never exceed 212°F, here is why: Assuming 1 gal is about 8 pounds, you are correct that it will require about 1136 BTU (of HEAT) to raise the TEMPERATURE from 70°F to 212°F (1BTU/lb/°F), however it will take another 7760 BTU to vaporize (boil) that gallon of water AT 212°F (970 BTU/lb). So while you are adding HEAT to the pot it is all consumed by the process of converting the water to water vapor (steam) and the TEMPERATURE remains a constant 212°F. So both the water and steam are are at the same TEMPERATURE (212°F) the steam contains more HEAT energy. Once it is a gas the temperature of the gas will continue to rise with added heat input (eg. convection from the stove). That water vapor will remain a gas until it looses the retained heat and condenses back into liquid water, like on your window. What we are talking about is heat of vaporization, the amount of heated need to vaporize (tear apart if you will) a liquid and turn it into a gas at a given temperature. While we are at it, the temperature (boiling point) varies with pressure, the higher the pressure, the higher the Boiling point. That is why it takes longer to boil an egg at high altitude, and how a pressure cooker can achieve higher temperatures than an open pot. Even the water in the unheated pans requires the same about of heat to evaporate, just more slowly at a lower temperature. Anyway, I wouldn't,t be carrying that pot around either LOL

I keep a cast iron pot on top of the DS but I put it on a trivet. The bottom of the pot is around 193* while the very top of the pot is 140* and the handle is 130*. It usually take about 3 days to evaporate the gallon of water. Even when the pot is empty and forgotten about on the stove the handle is never really too hot to grab and carry over to the sink to fill.

I use about 2-3 gallons a day and we hang laundry in the same room as the stove. We try to do a load-a-day so there will always be cloths hanging and laundry done. I agree with the clean laundry smell in the house. The max temp of the water on the stove has been is about 180*. I also have made chili, venison stew, and soup on the stove top. Seems like the perfect temp to let things simmer...

True the water stays at 212 in the pot and the steam comes off at 212. But now imagine a 1/2 or 1/3 full pot on top of a 500 stove top (no trivet) and the top of the pot is closed because plenty of steam is roaring out the stem, so I have measured the pot in the 240-280 range and the steam is heated in that pot beyond 212. A full pot would be much cooler and the pot as it empties out (yes I often ran it dry) is much hotter. Anyway I had no concern about this with the Chubby or with spilling a few drops of water within reason. Of course, I filled the empty hot pot very slowly so as not to thermally shock it too much.
PS and the 1000 BTU to raise the temp happens relatively quickly while the (larger) energy absorbed to vaporize occurs over a very much longer time scale (BTU per hour is small).

lobsterman wrote:True the water stays at 212 in the pot and the steam comes off at 212. But now imagine a 1/2 or 1/3 full pot on top of a 500 stove top (no trivet) and the top of the pot is closed because plenty of steam is roaring out the stem, so I have measured the pot in the 240-280 range and the steam is heated in that pot beyond 212. A full pot would be much cooler and the pot as it empties out (yes I often ran it dry) is much hotter. Anyway I had no concern about this with the Chubby or with spilling a few drops of water within reason. Of course, I filled the empty hot pot very slowly so as not to thermally shock it too much.
PS and the 1000 BTU to raise the temp happens relatively quickly while the (larger) energy absorbed to vaporize occurs over a very much longer time scale (BTU per hour is small).

Ya got two things working here, in a closed pot the pressure increases, raising the boiling point (a little), and the trapped water vapor is much less dense than the water (about 1 gram/liter vs water at 1000 grams/ liter) and the specific heat is only about half as much as water both the pot above the water and the steam inside could very rapidly be heated by a combination of convection, and radiation from the hot stove to those temperatures. With a open pot where the vapor is free to escape, this is much less likely to happen. Toss in a couple of those lobsters LOL.

stonyloam wrote:

lobsterman wrote:True the water stays at 212 in the pot and the steam comes off at 212. But now imagine a 1/2 or 1/3 full pot on top of a 500 stove top (no trivet) and the top of the pot is closed because plenty of steam is roaring out the stem, so I have measured the pot in the 240-280 range and the steam is heated in that pot beyond 212. A full pot would be much cooler and the pot as it empties out (yes I often ran it dry) is much hotter. Anyway I had no concern about this with the Chubby or with spilling a few drops of water within reason. Of course, I filled the empty hot pot very slowly so as not to thermally shock it too much.
PS and the 1000 BTU to raise the temp happens relatively quickly while the (larger) energy absorbed to vaporize occurs over a very much longer time scale (BTU per hour is small).

Ya got two things working here, in a closed pot the pressure increases, raising the boiling point (a little), and the trapped water vapor is much less dense than the water (about 1 gram/liter vs water at 1000 grams/ liter) and the specific heat is only about half as much as water both the pot above the water and the steam inside could very rapidly be heated by a combination of convection, and radiation from the hot stove to those temperatures. With a open pot where the vapor is free to escape, this is much less likely to happen. Toss in a couple of those lobsters LOL.

Agreed!