A question about boiling water and peas
Discussion
I was cooking dinner tonight, and poored the boiling water from the kettle onto my frozen peas and wondered a question that I have, if I'm honest, wondered before...
Obviously it takes longer to boil a large quantity of water than it does a smaller qunatity. However, when adding already boiling water to peas would using a larger volume and therefore a smaller overall cooling effect from the frozen peas be beneficial compared to using a smaller volume which would not take as long to boil if peas were not involved?
I would have thought that the answer would be that the optimum volume would be a midway point, but then given a very small amount of peas (say 5) and a lot of boling water (say two litres) the cooling affect would be so small, that it should be able to re-boil fairly quickly, but then at the other end again with 5 peas, adding just enough water to cover the peas would not take long to boil in the first place.
Anyone know for sure? Obviously this is very crucial infomation as this day and age, saving on energy costs os very important and the less gas used bring peas to the boil, the more money in my pocket
Obviously it takes longer to boil a large quantity of water than it does a smaller qunatity. However, when adding already boiling water to peas would using a larger volume and therefore a smaller overall cooling effect from the frozen peas be beneficial compared to using a smaller volume which would not take as long to boil if peas were not involved?
I would have thought that the answer would be that the optimum volume would be a midway point, but then given a very small amount of peas (say 5) and a lot of boling water (say two litres) the cooling affect would be so small, that it should be able to re-boil fairly quickly, but then at the other end again with 5 peas, adding just enough water to cover the peas would not take long to boil in the first place.
Anyone know for sure? Obviously this is very crucial infomation as this day and age, saving on energy costs os very important and the less gas used bring peas to the boil, the more money in my pocket
Heating water requires a lot of energy, so you don't want to be heating more of it than you need.
The peas are going to need a set amount of energy to raise their temperature, and this can come either from the kettle element or the hob.
Kettles are very efficient ways of heating water, but hobs much less so because a lot of heat is lost to the room. The first site I turned up on Google appeared to suggest that a hob is only about 30% efficient. However, gas appears to be about a third the price of electricity per kWh so I reckon that'll pretty much balance out and the costs will be similar.
I reckon the cheapest method is to heat just enough water to cover the peas in the kettle and supply the rest of the energy using the hob.
The peas are going to need a set amount of energy to raise their temperature, and this can come either from the kettle element or the hob.
Kettles are very efficient ways of heating water, but hobs much less so because a lot of heat is lost to the room. The first site I turned up on Google appeared to suggest that a hob is only about 30% efficient. However, gas appears to be about a third the price of electricity per kWh so I reckon that'll pretty much balance out and the costs will be similar.
I reckon the cheapest method is to heat just enough water to cover the peas in the kettle and supply the rest of the energy using the hob.
- Something I have thought about for yearsEggman said:
Heating water requires a lot of energy, so you don't want to be heating more of it than you need.
The peas are going to need a set amount of energy to raise their temperature, and this can come either from the kettle element or the hob.
Kettles are very efficient ways of heating water, but hobs much less so because a lot of heat is lost to the room. The first site I turned up on Google appeared to suggest that a hob is only about 30% efficient. However, gas appears to be about a third the price of electricity per kWh so I reckon that'll pretty much balance out and the costs will be similar.
I reckon the cheapest method is to heat just enough water to cover the peas in the kettle and supply the rest of the energy using the hob.
I expect you're right for total energy consumption but my question really is ignoring the energy used to boil the water in the first place. Simply, which way around will allow the water to boil first, more or less water.The peas are going to need a set amount of energy to raise their temperature, and this can come either from the kettle element or the hob.
Kettles are very efficient ways of heating water, but hobs much less so because a lot of heat is lost to the room. The first site I turned up on Google appeared to suggest that a hob is only about 30% efficient. However, gas appears to be about a third the price of electricity per kWh so I reckon that'll pretty much balance out and the costs will be similar.
I reckon the cheapest method is to heat just enough water to cover the peas in the kettle and supply the rest of the energy using the hob.
My last comment about cost was rather tounge in cheek, but did kind of distract from the actual question.
balders118 said:
Simply, which way around will allow the water to boil first, more or less water.
I suspect that as long as the quantity of water is large in relation to the volume of peas it won't make much difference. I reckon 'large' in this context means that there's enough water that water and peas would quickly end up at a uniform temperature, thereby excluding scenarios like adding a drop of hot water to a cubic metre of peas. Once you've got that. the peas will take X joules of energy out of the (boiling) water whether it's half a pint or a gallon and the hob will have to supply X joules to get it boiling again, plus whatever escapes to heat the room. As the hob isn't that efficient, if the article I looked at earlier is right it'll have to supply about 3X joules to heat it up.
Famous Graham said:
balders118 said:
russ_a said:
.
When im fact I meant that hot water freezes faster than cold water
Well, thats not actually true now is it.When im fact I meant that hot water freezes faster than cold water
Edited by russ_a on Tuesday 5th June 23:46
balders118 said:
Famous Graham said:
balders118 said:
russ_a said:
.
When im fact I meant that hot water freezes faster than cold water
Well, thats not actually true now is it.When im fact I meant that hot water freezes faster than cold water
Edited by russ_a on Tuesday 5th June 23:46
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