Cooking by Energy or Temperature settings and modifying

[ericmark]

When the gas cooker arrived on the seen the British house wife had to get use to using Energy rather than Temperature for oven control. Energy has always been the way hobs worked there have been one or two where probes could be used or it sensed centre of pan temperature but rare.

Microwaves in the 90's did start having probes but again in the main work on energy delivered rather than temperature.

The solid fuel and electric oven has always used temperature and there has never been a move to use the gas mark system with electric or solid fuel.

Often the temperature is controlled by boiling point and pressure cookers work at a range of pressures and as a result also a range of temperatures.

A slow cooker is very like an oven it can have either temperature or energy control so as with the gas mark system it can have 180W of power may be with an option to reduce with instead of Mark settings a simple off, Warm, Low, High setting. Or it can have a sensor and maintain food at 71~93 °C main point is it does not boil the food.

This not boiling has a advantage of retaining vitamins and a disadvantage of not destroying some of the toxins found in some beans.

So my wife buys a Tesco SCSS12 Slow cooker which says on the box "3 Temperature settings" but the instructions only call it off, warm, low, high with no temperatures shown.

Looking at the build I can't see how it would detect the temperature and the neon has two light levels between low and high but never switches off. And the riveted construction means not easy to see inside.

I can as with my beer brewing build a temperature controller but would guess if designed to use temperature control the element would be bigger than if designed as a power controlled device. So not sure adding on a temperature controller is really a good idea.

After being on a few hours the water was boiling which makes me think no temperature control even if it does say it has one on the box.

Since the recipes vary between types I do need to know which type. As to if worth taking back if it does not have temperature control I don't know.

After an hour the outside skin temperature was 58° C under the lid centre of food was 60.2° C so losses wise very little difference between the slow cooker and a simple pan. Only thing that may stop one using a hob and simple pan is the auto holiday shut down it does not say in cooker manual the maximum time you can use a hob for before it auto switches off.

In a casserole dish in the oven the moisture would not condense back into the dish as the lid would be too hot. But the sides of the oven are very well insulated so likely it would use less energy.

Since the outer skin is so hot ambient temperature and any drafts will clearly alter the temperature climbing it seems to be around 5° C per 15 minutes so it takes around 4 to 6 hours to hit 100° C so at around 7 - 8 hours it's been at boiling point for 1 - 2 hours but to me rather hit and miss.

Clearly not all slow cookers are the same and some are very well insulated and thermostatically controlled with a duel temperature first bringing it to boil and then an extended simmer with a delay timer.

TABLE 42.1 it would seem will allow the side to heat to 80° C (A part which need not be touched for normal operation) comparing inside and outside temperatures knowing in the end inside boils this unit must be very close to the limit. How any one doing a portable appliance test could find this out is another thing as 8 hours is a tad too long for a single PAT test.

Any feed back please?

 

[JohnW2]

When the gas cooker arrived on the seen the British house wife had to get use to using Energy rather than Temperature for oven control.

I don't understand what you mean by 'using energy rather than temperature' and, in any event, gas cookers were 'on the scene' before many households had electricity, let alone electric cookers!

The solid fuel and electric oven has always used temperature and there has never been a move to use the gas mark system with electric or solid fuel.

Again, I don't understand this. I'm not sure how it came about, but the "gas mark system" is merely another temperature scale, just like Fahrenheit or Celsius. AiUI, for 'gas marks' of 1 and above, if you multiply gas mark by 14 and add 121, you get the approximate (within 1 degree) Celsius temperature; below 'mark 1', there are 25°F steps between 'mark ¼', 'mark ½' and 'mark 1'.....

Mark °F °C
1⁄4 225° 107°
1⁄2 250° 121°
1 275° 135°
2 300° 149°
3 325° 163°
4 350° 177°
5 375° 191°
6 400° 204°
7 425° 218°
8 450° 232°
9 475° 246°

Kind Regards, John

 

[ban-all-sheds]

gas cookers were 'on the scene' before many households had electricity, let alone electric cookers!

http://en.wikipedia.org/wiki/Gas_Mark#History

AiUI, for 'gas marks' of 1 and above, if you multiply gas mark by 14 and add 121, you get the approximate (within 1 degree) Celsius temperature;

Which makes perfect sense.

Plan B - Ask Mrs Sheds who seems to have committed the equivalence table to memory.

Plan C - realise that there are thousands of yummie-mummies managing to cope with Agas which have no temperature controls, just a choice of ovens which work at different approximate temperatures, and that for thousands of years people managed to cook with no controls at all. Let go of your anal obsession with temperature control, and pay attention to how the food is doing.

 

[JohnW2]

http://en.wikipedia.org/wiki/Gas_Mark#History

Yes, I'm aware of that, but (unlike, say, the Fahrenheit and Centigrade/Celsius scales) I'm still not clear as to how the 'gas mark' scale came about.

... Which makes perfect sense. ... Plan B - Ask Mrs Sheds who seems to have committed the equivalence table to memory. ... Plan C - realise that there are thousands of yummie-mummies managing to cope with Agas which have no temperature controls, just a choice of ovens which work at different approximate temperatures ...

Yep, I've lived with one for the last few few decades, although I'm not sure whether she answers to the name of "yummie-mummy"

Kind Regards, John

 

[ericmark]

Be it a hob marked 1 ~ 9 or a oven marked 1⁄4 to 9 it was an energy rating or how much electric or gas was used rather than a temperature. OK it would after being on for some time relate to a temperature but it was the amount of energy used rather than the temperature achieved.

With a solid fuel you had a temperature gauge built into the door. It was a coil of metal which moved a needle but one pushed the damper in or pulled the damper out to get the desired temperature which directed the flue gases around the oven or bypassed it. Of course the fire also made a difference but to burn efficient the flue temperature should be around 150°C above that heat is waisted below that tar build up is a problem.

The electric oven did not have a temperature gauge but it did have a light which once switching on and off showed the oven was at the set temperature.

Both the solid fuel and electric oven were sealed from outside and to some extent insulated and until modern times were rather dry. No moisture was introduced.

The gas oven was very different it has both ventilation and added moisture from the burning of the gas as well as many other nasty by products from the gas. Coal tar was clearly before the big conversion added to anything cooked in a gas oven.

The conversion to North Sea gas really improved the taste of food cooked by gas as no longer was coal tar added to the food. However sulphur although should have been scrubbed from the gas still ended up in the food.

Although solid fuel should have been better in real terms fuel gases still got into the oven and food cooked in a solid fuel oven was better than gas and more moist than electric like gas it still had some by products which ended up in the food.

As time went on electric started to have fans and moisture systems added and left both gas and solid fuel behind. By adding more insulation they also became far more efficient.

However gas was the odd one out with no temperature gauge and it took some skill for the cook to know when to place the food in the oven.

As already stated this was nothing new placing coals in an oven to warm it up then racking out the coals and placing bread in the pre-heated oven has been done for thousands of years. As has the idea of a straw oven this time using the insulating qualities of the straw to maintain the temperature for long enough to cook the food in the oven.

As all ready stated the idea of using stored energy rather than a temperature is nothing new.

However I still feel three temperature settings should be three temperature settings not three energy setting.

We today are taught in school the difference between Joules and Watts and also between temperature and energy it is rather basic principles and one would hope children when they leave school have very little problem working out calories (4.2 joules) and Watts (Horse power) and be it a BTU or kWH or joule or calorie realise the difference to units using time like the Watt or Horse power and it's not really rocket science to work out if an item has three temperature settings or three energy settings.

Hi Mr Palmer,


Thank you for taking the time to contact our E-mails Department,


I have now forwarded this question to the manufacturer to see if there is any more information we can get.


This can unfortunately take a few weeks to come back with a result.


I will be back in touch as soon as I can


If you have any further queries please don’t hesitate in contacting me.


Kind regards


Kelly Neary
Tesco Technical Support
Customer Service Manager

This is a "Technical Support" who does not know the difference it seems between Energy and Temperature!

I do think there is a place for cookers using energy settings be it the gas oven or the standard hob but if it has three energy settings then what is wrong with calling it three energy settings rather than call it three temperature settings?

 

[Aragorn84]

I'm fairly sure thats not how most modern gas ovens operate.

The ones i've used have all had two burner modes, "Full" and "low", and a thermostat is used to switch between the two modes as appropriate. This means its temperature controlled, not energy.

If the 1-9 instead represented an energy value, then it would operate more like a gas ring, where the gas flow is constant relative to the position of the knob.

Ofcourse many gas hobs dont actually have any number values at all attached to the burners.

 

[JohnW2]

Be it a hob marked 1 ~ 9 or a oven marked 1⁄4 to 9 it was an energy rating or how much electric or gas was used rather than a temperature. OK it would after being on for some time relate to a temperature but it was the amount of energy used rather than the temperature achieved.

Maybe you've experienced different cookers from me, but with both gas and electrical ones I've had or experienced, the control set the trip level of a thermostat - so was essentially a 'temperature control' - just like a wall stat for CH. Thus, when you turned a gas oven on from cold, it would initial burn (energy) at full blast, whether it was set to '1' or '9', then reducing (or even extinguishing it, other than a pilot) the flame as one reached the set temperature. Indeed, even my (LPG) Aga has a thermostat which does that - although one never normally alters it once initially set (since it takes hours for the temperature to actually change!).

Kind Regards, John

 

[ericmark]

Be it a hob marked 1 ~ 9 or a oven marked 1⁄4 to 9 it was an energy rating or how much electric or gas was used rather than a temperature. OK it would after being on for some time relate to a temperature but it was the amount of energy used rather than the temperature achieved.

Maybe you've experienced different cookers from me, but with both gas and electrical ones I've had or experienced, the control set the trip level of a thermostat - so was essentially a 'temperature control' - just like a wall stat for CH. Thus, when you turned a gas oven on from cold, it would initial burn (energy) at full blast, whether it was set to '1' or '9', then reducing (or even extinguishing it, other than a pilot) the flame as one reached the set temperature. Indeed, even my (LPG) Aga has a thermostat which does that - although one never normally alters it once initially set (since it takes hours for the temperature to actually change!).

Kind Regards, John

May be the modern oven does have thermostatic control in the main gas cookers I have used are in caravans where in real terms we have no option. And with the old types I have used the control for hob and oven were the same. It simply controlled the energy.

Because of the dangers associated with gas I would not allow a gas cooker in the house. There is a reason why they were banned from high rise flats they were simply not safe.

With the caravan I have no option it's gas or nothing the idea of a gipsy type caravan with solid fuel may appeal but I don't have a commercial type vehicle to tow it with so it's just not an option.

So my use of gas ovens goes back to the era of using town gas or coal gas and I remember the taste of tar in the cakes compared with those cooked with a solid fuel oven in my case coke which was sold off cheap as too small for the blast furnace.

Where I lived only the poor (I.e. non steel workers) used gas. Most steel workers used coke and solid fuel fires and cookers.

I do see how today with north sea gas there may be a good reason to use it. But I remember avoiding anything cooked in a gas oven due to the tar taste and sorry I would not use gas other than for central heating where all venting is done to out doors. I use open flue cookers and heaters only in the caravan not elsewhere.

Well OK I have one open flue fire for emergency use. Should the electric fail I will use the open flue fire but I can count on one hand how many times it's been used.

 

[JohnW2]

May be the modern oven does have thermostatic control in the main gas cookers I have used are in caravans where in real terms we have no option. And with the old types I have used the control for hob and oven were the same. It simply controlled the energy.

I wasn't necessarily talking about particularly 'modern' ones, but I've never seen one without thermostatic control. I really can't see how it would be safe. With a thermostatically controlled oven (whether gas or electric), even when the thermostat is set to the highest temperature, the flame/element cycles on and off. If it weren't for the thermostatic control, if the control was set to 'maximum energy', the temperature would keep climbing until something catastrophic happened, wouldn't it?

Kind Regards, John

 

[ericmark]

With electric yes but gas has to have an air flow so even without a thermostat there is a maximum temperature.

This is the whole problem with gas the flame is actually in the oven. With electric the element heats the oven but is not normally exposed. Even with a fan oven it's the same air circulating. There is no reason why a gas oven does not have a balanced flue it would be possible but they simply don't.

 

[JohnW2]

With electric yes but gas has to have an air flow so even without a thermostat there is a maximum temperature.

True - but in the absence of thermostatic control, that 'maximum temperature' could still be dangerously high, couldn't it?

Kind Regards, John

 

[ericmark]

With electric yes but gas has to have an air flow so even without a thermostat there is a maximum temperature.

True - but in the absence of thermostatic control, that 'maximum temperature' could still be dangerously high, couldn't it?

Kind Regards, John

Until it melts something next to it no real danger unlike electric there is not anything in the cooker to melt.

I had a job installing cookers for a short time and with gas the regulations are very strict again and again we would bring gas cookers back with us as the cupboards were too close but we would have fitted electric without a problem.

My electric cooker is a tight fit in the units that would not be allowed with gas. Unlike electric they have no cooling fans so stand alone really means stand alone with a gap all around them.

However it was not gas cookers I was talking about it was an electric slow cooker. I posted on a few places to see what others thought and on one some one came back and said how they put a towel over theirs and it worked a lot better. I then re-read the instructions. It does say "Do not use attachments or accessories which are not recommended by the manufacture." but nothing about not covering and since it does not say who is the manufacturer how would one know what they recommend?

I have always considered Tesco as a good shop and expect to find good quality. If bought from Ikea or QVC I would be wary but Tesco I have assumed have good buyers who select goods carefully.

The User Guide has no recipes so one has to crawl the net to find them. This is when I realised there was a problem as it seems recipes are matched to the device.

It states:-

Do not preheat the slow cooker before use unless expressly recommended in your recipe

But since there are no recipes with the cooker and one has to get them all from else where what is the point in that? Any one can write the recipe so any one can say pre-heat and then it's OK?

I think it will gather dust with many of the other silly ideas my wife seems to have. Some I must admit work well the microwave pressure cooker was a real hit it works well. The soup maker takes that long to clean and so until I have lost all my teeth it sits on top of the fridge.

The juicer gets used once a year by me to make cider and at about 6 litres a year it would have been cheaper to bin the apples and buy three bottles of cider a year.

Hostess sits on top of the drinks cabinet and comes out at Christmas last year it was not used at all just a hot plate. And when she bought the electric hot plate did she dump those silly candle things no way.

So the slow cooker really got up my nose it's just another load of junk to move around the kitchen. May be some people have a use for it but I was rather peeved to find in spite of having in large writing 3 temperature settings it clearly has just 3 heat settings or energy settings non of them set the temperature.

Clearly Tesco don't know English and are unaware that temperature is different to energy even if related.

 

[Aragorn84]

Maybe they ARE temperature settings, but just of an unknown value?

Open it up and have a look?

Or stick a watt meter on it and see if each setting draws more or less power?

 

[JohnW2]

True - but in the absence of thermostatic control, that 'maximum temperature' could still be dangerously high, couldn't it?

Until it melts something next to it no real danger unlike electric there is not anything in the cooker to melt.

It could surely become a hazard to anyone who touched it long before it melted the surroundings?

Unlike electric they [gas cookers have no cooling fans so stand alone really means stand alone with a gap all around them.

Albeit I haven't had one for a long time, I have never had an electric cooker which has a fan. Furthermore, as you've said, unlike electric cookers, gas ones necessarily have ventilation.

However it was not gas cookers I was talking about it was an electric slow cooker.

I have been responding to your comments about the 'gas mark' temperature scale, which you claimed was not a temperature scale.

I posted on a few places to see what others thought and on one some one came back and said how they put a towel over theirs and it worked a lot better.

I can well believe that slow cookers, like electric blankets etc., are a 'special case'. The energy consumption is so low that they may well not have thermostatic control and, instead, rely on reaching thermal equilibrium with the surroundings, whilst the element remains on constantly, supplying constant energy). That's certainly true of every electric blanket I've ever owned. Just as the 'put a towel over it' comment above, if one puts more bedclothes over the electric blanket, the temperature achieved will increase. So, yes, I would expect slow cookers (just like electric blankets) to have just energy' controls - either simple on/off or two or three (fixed and continuous) energy settings.

Kind Regards, John