Why does boiling soup not steam?

Russinating · 26 Jan 2011 at 19:39

I was just cooking some soup, as you do, and noticed that whilst on the heat and boiling it didn't release any steam, yet as soon as you take the pot off the heat it steams as much as a kettle.

Why is that?!

Freefaller · 26 Jan 2011 at 19:41

Possibly because the heat coming off the hob is so high that steam cannot form?

joeyjojo · 26 Jan 2011 at 19:44

I was wondering the same thing!

We concluded that as the stuff is boiling, the vapour coming off is so hot that it doesn't condense until later when it's risen, so you don't see it. However, when you turn the hob off and the soup cools down, the vapour condenses almost immediately and you see it.

cheets64 · 26 Jan 2011 at 19:49

because its not water, tomato vapor

arknor · 26 Jan 2011 at 19:53

if it doesnt release any steam why does the saucepan lid get covered in it? if theres no lid i wonder where it goes

if you left soup boiling forever and there was no steam it would never boil dry

Nitefly · 26 Jan 2011 at 19:57

I was wondering this today too

Castiel · 26 Jan 2011 at 19:58

Nitefly said:
I was wondering this today too

I wasn't wondering, but I am now....dammit!

I suspect however that the steam is caused by the cooling of the soup and not the heating.

btw OP, you shouldn't boil soup, it ruins it.

Judgeneo · 26 Jan 2011 at 19:59

It does steam, its just you cant see it.

The heat from the rest of the hob heats up the air above the saucepan so that the steam cannot condense, and you can only see water once it has condensed.
When you take the saucepan of the hob, the steam is now rising into cool air, and can as such condense, so you see a big plume of the stuff

Same with all cooking, nothing special about soup

Castiel · 26 Jan 2011 at 20:04

Judgeneo said:
It does steam, its just you cant see it.

The heat from the rest of the hob heats up the air above the saucepan so that the steam cannot condense, and you can only see water once it has condensed.
When you take the saucepan of the hob, the steam is now rising into cool air, and can as such condense, so you see a big plume of the stuff

Same with all cooking, nothing special about soup

Why is it then that when potatoes are boiling there is steam?

Participant · 26 Jan 2011 at 20:04

cheets64 said:
because its not water, tomato vapor

Lolwut

Judgeneo · 26 Jan 2011 at 20:05

Castiel said:
Why is it then that when potatoes are boiling there is steam?

There is something wrong with your potatoes.... Better get that checked out man, serious stuff

[FnG]magnolia · 26 Jan 2011 at 20:05

I don't know the answer but you shouldn't be boiling soup. It can ruin the taste.

Russinating · 26 Jan 2011 at 20:07

Judgeneo said:
There is something wrong with your potatoes.... Better get that checked out man, serious stuff

Pasta steams!

Castiel · 26 Jan 2011 at 20:08

Judgeneo said:
There is something wrong with your potatoes.... Better get that checked out man, serious stuff

Lol, it must be some kinda disease, because the Pasta does it too, and the milk!

arknor · 26 Jan 2011 at 20:09

no it doesnt the water steams the pasta cooks and the potatoes boil

soup should simmer on the hob

Vonhelmet · 26 Jan 2011 at 20:22

Water vapour != steam.

Hotwired · 26 Jan 2011 at 20:29

vonhelmet said:
Water vapour != steam.

True dat.

Steam is just another transparent gas. However when your average joe is in view of steam it's not generally at an ideal temperature to be steam.

It's instead at the kind of temperature it starts condensing back to water which is visible in the air.

Steam if hot enough is entirely dry as well, you only get condensation if it is allowed to cool enough to return to liquid.

Bes · 26 Jan 2011 at 20:51

Never mind this steam rubbish.... Why are you all boiling your milk and soup? Does no one know how to cook any more?!!

p4radox · 26 Jan 2011 at 20:55

Steam is invisible. Boiling soup does steam.

edit: beaten:

Hotwired said:
True dat.

Steam is just another transparent gas. However when your average joe is in view of steam it's not generally at an ideal temperature to be steam.

It's instead at the kind of temperature it starts condensing back to water which is visible in the air.

Steam if hot enough is entirely dry as well, you only get condensation if it is allowed to cool enough to return to liquid.

True dat. For example in the massive steam turbines used for power generation "wet" steam is seriously bad news. If it's not completely dry then the droplets can reach such high velocities they wear out the turbine blades. :cool:

whitecrook · 26 Jan 2011 at 21:26

Look at your kettle boiling. Look at the spout. See the 'gap' between the spout and the 'steam' ? That gap is actually the steam. The 'steam' you can see is water vapour.