Steaming. Temperature. Concept. Questions.

[skyhskyh]

Hello.

1. Is the Maximum temperature for steaming is 100 degree celsius?

2. When steaming below 100 degree celsius, what makes it less than 100 degree since for the water to turn into steam, it needs 100 degree.

3. Steam cooking. Is it like pan frying where the heat transfer is mainly from below going up only. (whereas in ovens, it's from all sides)

***

My Thinking:

Is it the density of water vapours in the air that the food is being surrounded?

That is, more vapour "bubbles" in the air, higher the chance and more number of vapour can be condensed on the food surfaces, hence transferring heat to the food.

Less "bubbles", less water vapours can be condensed on the food, hence less heat, and hence, lower cooking temperature?

***

Accordingly, to get lower than 100 degree, three methods I can think of and how the science behind it:

The liquid producing the steam is not boiling, so giving less vapours up to the air even though those bubbles are still 100 degree?

With lid open, the steam coming up, some escaped to other places, or got blown away, hence not much vapours can be landed on the food, hence less hot?

With electronic steamer, I guess it produce less vapours than if steaming at 99 degrees celsius?

Thanks

Edited September 6, 2012 by skyhskyh (log)

[phatj]

Hello.

1. Is the Maximum temperature for steaming is 100 degree celsius?

At sea-level pressure. At high altitude, water boils at below 100 C; below sea level, above 100 C.

2. When steaming below 100 degree celsius, what makes it less than 100 degree since for the water to turn into steam, it needs 100 degree.

This is not correct. Steam is simply water vapor; it can form at any temperature. In fact, ice can and does convert from solid phase to gaseous (sublimation) at below freezing, let alone boiling. The higher the temperature, the faster the water evaporates. 100 C is simply the temperature at which water at sea level cannot remain liquid.

3. Steam cooking. Is it like pan frying where the heat transfer is mainly from below going up only. (whereas in ovens, it's from all sides)

Steaming is very even, as it works by convection of hot water vapor, and by conduction, from condensed water, now less hot than the vapor. It imagine it would heat even more evenly than ovens, since in steaming the surrounding vessel will be pretty close to the same temperature as the vapor, whereas in an oven the heating element in the bottom or wherever is much hotter and radiates.

***

My Thinking:

Is it the density of water vapours in the air that the food is being surrounded?

That is, more vapour "bubbles" in the air, higher the chance and more number of vapour can be condensed on the food surfaces, hence transferring heat to the food.

Less "bubbles", less water vapours can be condensed on the food, hence less heat, and hence, lower cooking temperature?

Not really sure what you're getting at here. I'm not sure what happens to the "density of water vapours" but I'm pretty sure it has little to do with the temperature.

***

Accordingly, to get lower than 100 degree, three methods I can think of and how the science behind it:

The liquid producing the steam is not boiling, so giving less vapours up to the air even though those bubbles are still 100 degree?

With lid open, the steam coming up, some escaped to other places, or got blown away, hence not much vapours can be landed on the food, hence less hot?

With electronic steamer, I guess it produce less vapours than if steaming at 99 degrees celsius?

The "steam bubbles" produced are only 100C if the water producing them is 100C. If you want to "steam" something at a lower temperature, you need to arrange a steaming chamber where the water isn't boiling. For instance, construct a sous vide rig in an insulated chamber like a cooler, and hang the stuff you want to steam above the level of the water. Sous vapeur, if you will.

[kostbill]

Host's note: the following discussion has been moved from the Anova Precision Oven topic because its general thermodynamical nature is not specific to a single model of steam oven. The term "APO" refers to the Anova Precision Oven. The term "CSO" refers to the Cuisinart Steam Oven.

 

I have a question: is there in the APO a mode to cook with steam, in temperatures higher than 100C?

 

If so, when the steam is inserted in the oven, the wet bulb temperature will stay of course, below 100C,

then the cooked item will not cook just like a normal oven, because even in the normal oven the cooked

item generates humidity.

 

The difference I see is that in the case of the inserted steam, we will have more steam.

 

So, what is the meaning of cooking with steam at temperatures above 100C?

Edited December 20, 2020 by Smithy
Added host's note (log)

[rotuts]

the humid air delivers more energy to the food

 

over time , and the food cooks quicker 

 

and the food does not dry out

 

and yet , you get plenty of Maillard Rx.

 

review the CSO threads to see the results.

Edited December 18, 2020 by rotuts (log)

[kostbill]

 

OK your first line makes a lot of sense.

Humidity will provide energy faster to the food.

 

But then, does it matter if it is 1C above 100C or 200C above 100C?

 

Also, can you get Maillard reaction below 100C?

 

I have been reading the forum but there are so many things I don't understand.

[rotuts]

@kostbill 

 

good place to start on Mailliard Rx :

 

 

https://www.seriouseats.com/2017/04/what-is-maillard-reaction-cooking-science.html

 

you generally bake/cook in the closed steam oven at a slightly lower temp than a regular

 

dry oven.   and the cooking/baking is faster.

 

for bread , steam is only used for the first few minutes to get the ' spring ' of the crust

 

the dry oven.

 

almost all ' professional ' ovens have steam as an option 

 

they have not become ubiquitous in homes , as venting is a problem

 

w so much steam coming out of the oven when you first open the door.

 

also steam ovens ' steam clean '

 

professional ovens are ' plumbed in ' and washed in a cycle like a dish washer

 

thus the ' plumbed in ' aspect 

 

then you wipe them down , that simple.

 

there is the issue of a condensation collector under the oven.

 

take a look at this Bad Girl :

 

pretty snappy !

 

unfortunately most need 3 phase power

 

this one does not :

 

 

here is the spec sheet :

 

https://mcdonaldpaper.com/media/pdf/A618106.12.pdf

 

its $ 11,280.

 

and unlike the Anova , this puppy has free shipping !

 

don't know if it needs to be plumbed in , and needing a drain

 

 

 

 

 

Edited December 18, 2020 by rotuts (log)

[kostbill]

I have read that and many more, but perhaps I should refresh my memory.

[JoNorvelleWalker]

6 hours ago, kostbill said:

I have a question: is there in the APO a mode to cook with steam, in temperatures higher than 100C?

 

If so, when the steam is inserted in the oven, the wet bulb temperature will stay of course, below 100C,

then the cooked item will not cook just like a normal oven, because even in the normal oven the cooked

item generates humidity.

 

The difference I see is that in the case of the inserted steam, we will have more steam.

 

So, what is the meaning of cooking with steam at temperatures above 100C?

 

Above 100C the meaning of percent steam is how hard the oven's steam generator is working.  At 100% the oven is producing as much steam as it can.

 

[kostbill]

17 minutes ago, JoNorvelleWalker said:

 

Above 100C the meaning of percent steam is how hard the oven's steam generator is working.  At 100% the oven is producing as much steam as it can.

 

This seems right, but then, since the wet bulb temperature will never go above 100C, then why use the steam mode when we are above 100C?

[rotuts]

@kostbill 

 

Not quite right I think :

 

Wiki :

 

https://en.wikipedia.org/wiki/Wet-bulb_temperature

 

"""   The wet-bulb temperature (WBT) is the temperature read by a thermometer covered in water-soaked cloth (wet-bulb thermometer) over which air is passed.^[1] At 100% relative humidity, the wet-bulb temperature is equal to the air temperature (dry-bulb temperature); at lower humidity the wet-bulb temperature is lower than dry-bulb temperature because of evaporative cooling. """

 

I think WBT is useful under 100C   

 

if your oven is 100% saturated above 100 C , you get that temp , f fully saturated air

 

Rational oven :

 

 

I can't tell you what ' combination 30 t0 300 (C ) means

 

I don't have one.

 

Id love to have one to figure this out.  right now

 

its Ice and Snow on the driveway .

[gfweb]

Steam can exist in an oven hotter than 212F.

 

As I understand it, the wet bulb temp applies to a water-soaked object eg a piece of meat or a rag around a thermometer. The temp of the object wont get above 212F till at least the surface water is evaporated off.

 

It doesn't mean that the oven cannot get hotter than 212F and still contain steam.

 

I just put a thermometer in the cuisinart steam oven. Set the oven at 350F+steam.

Within a few minutes the steam-filled oven was at 240F and climbing.

[kostbill]

I am afraid I am not understood because English is not my mother language (or I am an idiot). Let me try again.

Facts (I think they are facts, correct me if I am wrong):

- Wet bulb temperature will ALWAYS be lower than 100C. Correct?

- Dry bulb temperature may very well be above that. But the wet bulb will be lower than 100C.

- As long as the cooking is happening with some percentage of steam, the item that is cooked, will be cooked with the wet bulb temperature.

Question:

- If we are cooking with steam, let's say 100%, why does it matter if the dry bulb temperature is 101C or 250C?

    rotuts provided a good explanation, that higher dry bulb temperature makes energy travels faster, but how is this translated to physics?

    Does it mean that the humidity in the item that is cooked, will be evaporated sooner?

- What happens if the steam is not 100%? The wet bulb temperature is even lower?

 

Thanks and sorry if my questions do not make sense.

[JoNorvelleWalker]

3 hours ago, kostbill said:

I am afraid I am not understood because English is not my mother language (or I am an idiot). Let me try again.

Facts (I think they are facts, correct me if I am wrong):

- Wet bulb temperature will ALWAYS be lower than 100C. Correct?

- Dry bulb temperature may very well be above that. But the wet bulb will be lower than 100C.

- As long as the cooking is happening with some percentage of steam, the item that is cooked, will be cooked with the wet bulb temperature.

Question:

- If we are cooking with steam, let's say 100%, why does it matter if the dry bulb temperature is 101C or 250C?

    rotuts provided a good explanation, that higher dry bulb temperature makes energy travels faster, but how is this translated to physics?

    Does it mean that the humidity in the item that is cooked, will be evaporated sooner?

- What happens if the steam is not 100%? The wet bulb temperature is even lower?

 

Thanks and sorry if my questions do not make sense.

 

I believe your third fact is incorrect.  I'm not sure what you mean by "steam is not 100%".  This is a good discussion, you are not an idiot.

 

 

[gfweb]

14 minutes ago, JoNorvelleWalker said:

 

I believe your third fact is incorrect.  I'm not sure what you mean by "steam is not 100%".  This is a good discussion, you are not an idiot.

 

 

Exactly what is meant by "100% steam"?

It can't mean that the only molecules in the oven are heated water. There's air in there too

[kostbill]

@gfweb and @JoNorvelleWalker,100% steam, or 100% humidity, means that the air cannot hold more steam, it reached its peaked amount of water it can hold.

 

@JoNorvelleWalker if the third fact "As long as the cooking is happening with some percentage of steam, the item that is cooked, will be cooked with the wet bulb temperature" is incorrect it would make a lot of sense, but I have no idea what else could be the case here.

[rotuts]

lets go back to what ' wet bulb temperature means and is supposed to measure :

 

https://en.wikipedia.org/wiki/Wet-bulb_tem…

 

The wet-bulb temperature (WBT) is the temperature read by a thermometer covered in water-soaked cloth (wet-bulb thermometer) over which air is passed.^[1] At 100% relative humidity, the wet-bulb temperature is equal to the air temperature (dry-bulb temperature); at lower humidity the wet-bulb temperature is lower than dry-bulb temperature because of evaporative cooling.

 

N.B.:  at 100 % humidity , WBT is the air temperature , as there will be no evaporative cooling

 

therefore  , at high humidity in a steam over , over 100 C ( 212 F ) there is no evaporative cooking.

 

your food , and the moisture on the food's surface does not evaporate , and the temp of the oven

 

determines cooking time , IE thermal transfer from the oven to the food

 

Infrared , contact  ( circulating moist air ) etc.

 

Wet Bulb temps require evaporation , at any temp.  above or below 100 C

 

in environments w 100 % humidity  , at all temperatures , WB = DB temp

Edited December 19, 2020 by rotuts (log)

[gfweb]

59 minutes ago, rotuts said:

lets go back to what ' wet bulb temperature means and is supposed to measure :

 

https://en.wikipedia.org/wiki/Wet-bulb_tem…

 

The wet-bulb temperature (WBT) is the temperature read by a thermometer covered in water-soaked cloth (wet-bulb thermometer) over which air is passed.^[1] At 100% relative humidity, the wet-bulb temperature is equal to the air temperature (dry-bulb temperature); at lower humidity the wet-bulb temperature is lower than dry-bulb temperature because of evaporative cooling.

 

N.B.:  at 100 % humidity , WBT is the air temperature , as there will be no evaporative cooling

 

therefore  , at high humidity in a steam over , over 100 C ( 212 F ) there is no evaporative cooking.

 

your food , and the moisture on the food's surface does not evaporate , and the temp of the oven

 

determines cooking time , IE thermal transfer from the oven to the food

 

Infrared , contact  ( circulating moist air ) etc.

 

Wet Bulb temps require evaporation , at any temp.  above or below 100 C

 

in environments w 100 % humidity  , at all temperatures , WB = DB temp

 

Thanks! That was more clarity  than I could muster earlier.

 

So to amplify...

 

 100% humidity..... speeds cooking by increased heat transfer...minimizes water loss from food...but still cooks at the temp at which the oven is set.

 

100% humidity doesn't cook everything at 100C no matter what the temp

 

Browning still happens at 100% humidity since browning has no dependence on meat water loss.

 

 

 

 

[rotuts]

and lets call ' steam '  water vapor above 100C that is condensing.

 

you open your CSO  at 350 F Steam-Bake :  you get some superheated

 

water vapor , hopefully no in your face.

 

water vapor can condense below 100 C :   Mist.fog etc

 

and for completeness sake :

 

water has a ' triple point '

 

where each phase ( liquid , vapor , solid )

 

is in equilibrium  .

 

not often useful in cooking.

Edited December 19, 2020 by rotuts (log)

[kostbill]

@rotuts you wrote that "in environments w 100 % humidity  , at all temperatures , WB = DB temp".

 

You mean that if DBT is 220C and we have 100% humidity, then WBT = 220C??

 

This is impressive. I don't understand it.

[rotuts]

@kostbill  

 

yes .  it's easy to understand once you grasp the concept

 

WBT was invented to give you an idea of  'heat effect'  at

 

dryer , or more humid normal living temps.

 

100 F  in a New England humid summer   

 

is going to feel quite different than 100 F  in the dry Arizona desert.

 

Ive lived in both places .  

 

that's all there is to it.

 

WBT isn't very helpful above 100 C.

[gfweb]

12 minutes ago, kostbill said:

@rotuts you wrote that "in environments w 100 % humidity  , at all temperatures , WB = DB temp".

 

You mean that if DBT is 220C and we have 100% humidity, then WBT = 220C??

 

This is impressive. I don't understand it.

 

In less than 100% humidity the Wet bulb is maintained at 100C by the cooling effect of evaporation. At 100% humidity no water can evaporate from the wet bulb, so its temp can rise.

[kostbill]

Thanks guys! That was super helpful.

[rotuts]

WBT  w humidity less than  100 %

 

at temps above 100 C   are going to be less than the DBT at those temps

 

I don't think the WBT automatically drops to 100 C

 

but Im starting to feel a little dehydrated myself , 

 

so some Personal Fluid Therapy is in order

 

sooner rather than a bit later.

 

    "  He's been known to pull a cork .... "

 

                Sheriff  in " True Grit "

 

                     mentioning Rooster Cogburn to Mattie Ross

 

a truly great line if there ever was one.

 

the book is even better than the movie , and the movie was mighty mighty fine.

 

 

 

 

[kayb]

3 hours ago, rotuts said:

 

the book is even better than the movie , and the movie was mighty mighty fine.

 

Charles Portis. A fine son of Arkansas, and an incredibly shy person. Hated to be asked about his books.

 

Read Dog of the South.

 

[rotuts]

@kayb  

 

read them all

 

w

 

Chips and Dps ?

 

something

 

you will not regret it

 

start w True Grit

Edited December 19, 2020 by rotuts (log)