90C Boiling Water Taps

[Ferdinand]

Do the Quookers of this world do water at 90C rather than 100C, in order to make better coffee?

 

A life and death issue.

 

Ferdinand

 

Edited March 10, 2020 by Ferdinand

[ProDave]

My Redring (Lamona Aka Howdens) one has an adjustment dial so if you were not after perfect tea, but instead wanted warm water for coffee you could do that.

[Jez1978]

Perrin and Rowe do a boiling tap ( 3 in 1) that has adjustable temp. 

[Ferdinand]

Thanks

[daiking]

I’m too lazy to work it out, how long would it take a litre of boiling water to cool to 90 degrees?

 

obviously surface area counts so a 2:1 height/width glass jug...

 

could that time be manageable? If a better tap were not capable of altering the temp in this way?

[ProDave]

Put a bit of cold water in first (10% of a cup full) then fill the rest with boiling.

 

Simples.

[gc100]

How do these taps work? So they keep a small reservoir at 100 or so they generate on the fly? Do they last as they seem very expensive compared to a kettle 

[Jeremy Harris]

  On 14/03/2020 at 13:04, gc100 said:

How do these taps work? So they keep a small reservoir at 100 or so they generate on the fly? Do they last as they seem very expensive compared to a kettle 

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Ours has a pressurised reservoir that sits underneath in the plinth area.  Holds a few litres of water at a bit above 100°C, at mains pressure.  Ours is now over 5 years old and has been used a lot in that time.  Seems cheaper to run than a kettle, partly because the power it draws during the day is often a lot lower than the power being generated by our PV system.  IIRC it uses about 20 W when in "keep hot" mode.

[gc100]

Thanks is that 20w/day? Seems very low. I suppose they used the same energy to bring fresh water to temp given physics! 

[Jeremy Harris]

  On 14/03/2020 at 13:12, gc100 said:

Thanks is that 20w/day? Seems very low. I suppose they used the same energy to bring fresh water to temp given physics! 

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No it's about 20 W all the time that it's switched on.  We have it on a time switch, so it comes on early in the morning and turns off in the evening.  Off the top of my head I think it's set to be on for about 15 hours a day, so roughly 300 Wh/day for the "keep hot" energy requirement, plus a bit used to heat from cold, or reheat after a cup, or saucepan, of hot water is drawn off.  When re-heating it uses around 1.5 kW, and takes a minute or two to get back up to temperature after a cup of tea has been made.  For much of the day the 20 W will come from the PV system, so I'd guess we're only paying for maybe 150 Wh/day for the "keep hot", plus maybe another 300 Wh or so per day for the re-heat energy.  All told it might cost around 7p or 8p per day to run.

 

It probably saves a fair bit of energy overall, as we often use the boiling water to cook vegetables, saving energy that would otherwise come from the hob.  It's also economical in terms of the amount of boiling water used for a cup of tea, as it's only ever re-heating the cupful that's been drawn, rather than a cupful plus a bit extra in a kettle.

[ryder72]

  On 14/03/2020 at 13:25, Jeremy Harris said:

 

No it's about 20 W all the time that it's switched on.  We have it on a time switch, so it comes on early in the morning and turns off in the evening.  Off the top of my head I think it's set to be on for about 15 hours a day, so roughly 300 Wh/day for the "keep hot" energy requirement, plus a bit used to heat from cold, or reheat after a cup, or saucepan, of hot water is drawn off.  When re-heating it uses around 1.5 kW, and takes a minute or two to get back up to temperature after a cup of tea has been made.  For much of the day the 20 W will come from the PV system, so I'd guess we're only paying for maybe 150 Wh/day for the "keep hot", plus maybe another 300 Wh or so per day for the re-heat energy.  All told it might cost around 7p or 8p per day to run.

 

It probably saves a fair bit of energy overall, as we often use the boiling water to cook vegetables, saving energy that would otherwise come from the hob.  It's also economical in terms of the amount of boiling water used for a cup of tea, as it's only ever re-heating the cupful that's been drawn, rather than a cupful plus a bit extra in a kettle.

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All good points Jeremy except the argument goes wobbly when one factors in the capital cost of a tap and say a 10 year service life.

 

The main reason to buy is convenience and time saved not having to wait around.

 

Its a worthwhile buy.

[ryder72]

In response to the OP's request - water is held pressurised a bit above boiling point and dispensed around 95-98 degrees. When one considers the temperate of the container that its poured out into, the heat loss probably cools it down to around the 90 degree point anyways. Of course this will depend on several factors such as the mass of the container and surface area in contact with water, temperature of the container, volume of water dispensed etc.

[Ferdinand]

  On 14/03/2020 at 14:30, ryder72 said:

In response to the OP's request - water is held pressurised a bit above boiling point and dispensed around 95-98 degrees. When one considers the temperate of the container that its poured out into, the heat loss probably cools it down to around the 90 degree point anyways. Of course this will depend on several factors such as the mass of the container and surface area in contact with water, temperature of the container, volume of water dispensed etc.

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And the u-value of the (insulated) coffee-pot ? .

[Jeremy Harris]

  On 14/03/2020 at 14:27, ryder72 said:

All good points Jeremy except the argument goes wobbly when one factors in the capital cost of a tap and say a 10 year service life.

 

The main reason to buy is convenience and time saved not having to wait around.

 

Its a worthwhile buy.

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I agree, but our Itho Daalderop 3 in 1 boiling water tap wasn't massively expensive.  We opted for the brushed stainless one and it cost a bit under £700 IIRC.  A similar quality 2 way mixer kitchen tap would probably have cost  a couple of hundred or so, so we probably paid around £400 more for the convenience of having boiling water on hand.   Definitely a "nice to have" rather than an essential, but not that much more cost overall when compared with a decent kitchen tap and the cost of two or three kettles over a ten year period.

 

 

  On 14/03/2020 at 14:30, ryder72 said:

In response to the OP's request - water is held pressurised a bit above boiling point and dispensed around 95-98 degrees. When one considers the temperate of the container that its poured out into, the heat loss probably cools it down to around the 90 degree point anyways. Of course this will depend on several factors such as the mass of the container and surface area in contact with water, temperature of the container, volume of water dispensed etc.

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In the case of our unit, the water is held at around 105°C to 108°C in the reservoir and when dispensed is actively boiling as it comes out of the tap, so very close to 100°C, and will sometimes continue boiling in the cup if that's already warm.  I may measure it later, just to be sure, but I'd be surprised if it drops to as low as 90°C until some time after it's been sat in the cup.  It looks very much as if the water coming out of the nozzle is still slightly superheated to me, as there is definitely a risk of scalding from the spitting as the pressure drops as it comes out and the water flash boils as a consequence.  You soon learn that there is a definite technique to using it, if you don't want to get splashed with boiling water.

 

[ryder72]

  On 14/03/2020 at 14:36, Ferdinand said:

 

And the u-value of the (insulated) coffee-pot ? .

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?

[ProDave]

  On 14/03/2020 at 14:27, ryder72 said:

 

 

All good points Jeremy except the argument goes wobbly when one factors in the capital cost of a tap and say a 10 year service life.

 

The main reason to buy is convenience and time saved not having to wait around.

 

Its a worthwhile buy.

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And less clutter.

 

With most things being built in, we only have ONE item permanently plugged in in the kitchen, and that is the toaster.  And I am really surprised there are no built in offerings for that.

[dpmiller]

how would someone go through multiple kettles in ten years?

[Jeremy Harris]

  On 14/03/2020 at 16:51, dpmiller said:

how would someone go through multiple kettles in ten years?

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At our old house we seemed to be lucky to get a kettle to last more than three or four years.  Didn't seem to matter whether we bought an expensive one or a cheap one, they seemed fail after about the same length of time.  Main problem is the very hard water, I think, it tends to kill kettles fairly quickly.  When we lived in Cornwall, and in Scotland, kettles seemed to last pretty much forever.

[Lesgrandepotato]

  On 14/03/2020 at 14:27, ryder72 said:

 

 

All good points Jeremy except the argument goes wobbly when one factors in the capital cost of a tap and say a 10 year service life.

 

The main reason to buy is convenience and time saved not having to wait around.

 

Its a worthwhile buy.

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 The main reason to buy is that you can make poached eggs as quickly as one can make toast. 
 

it’s life changing. 

[Ferdinand]

.

Edited March 14, 2020 by Ferdinand

[Ferdinand]

  On 14/03/2020 at 14:55, Jeremy Harris said:

  On 14/03/2020 at 14:27, ryder72 said:

All good points Jeremy except the argument goes wobbly when one factors in the capital cost of a tap and say a 10 year service life.

 

The main reason to buy is convenience and time saved not having to wait around.

 

Its a worthwhile buy.

Expand  

 

I agree, but our Itho Daalderop 3 in 1 boiling water tap wasn't massively expensive.  We opted for the brushed stainless one and it cost a bit under £700 IIRC.  A similar quality 2 way mixer kitchen tap would probably have cost  a couple of hundred or so, so we probably paid around £400 more for the convenience of having boiling water on hand.   Definitely a "nice to have" rather than an essential, but not that much more cost overall when compared with a decent kitchen tap and the cost of two or three kettles over a ten year period.

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 You'd better watch it, or he'll post the recursive spreadsheet cost model and the C02 emission analysis ... and the database of kettle lifetimes and survey of Kettle MTBFs in a the village at a 95% confidence level to show that 2 or 3 per 10 years is accurate at the prevailing local profile of measured temperatures since 2013.

 

 ?

 

  On 14/03/2020 at 17:25, Lesgrandepotato said:

The main reason to buy is that you can make poached eggs as quickly as one can make toast. 

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I am a founder member of the Slow Poached Egg movement.

 

The important thing is to be able to break an egg in one hand like Len Deighton. 

 

Edited March 14, 2020 by Ferdinand

[gc100]

How well wound these last in a hard water area?

thanks 

Edited March 15, 2020 by gc100

[Jeremy Harris]

  On 15/03/2020 at 07:58, gc100 said:

How well wound these last in a hard water area?

thanks 

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They come with a phosphate dosing filter to reduce the build up of limescale, or at least ours did.

[Jez1978]

No the sure on the others but with quooker you can purchase an additional scale control unit. Given the cost of the tap I think it's worth the extra couple of hundred quid, I've just brought a quooker and opted for one myself!

[Ferdinand]

Thanks for all the comments here.

 

F