# SV - Boiling temperature inside the bag - fake science



## atomicsmoke (Nov 5, 2018)

One of the SV machine makers  recommends in its website using ziploc bags instead of vacuum sealed bags. The reason: pressure inside the vacuum bags is very low, so the water in the food (that's in the bag) will boil at lower temp, possibly your cooking temp and will ruin the texture.

But the bag is immersed in liquid which applies 1 bar of pressure all over the bag. If it were that easy to maintain low pressure in a high pressure surrounding submarines would be made paper thin.


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## SonnyE (Nov 5, 2018)

Interesting summation on their part.
But I think it is totally wrong. The bag (regardless of who makes it) collapses because the air/gases inside is evacuated.
At that point there is no pressure differential between the inside and outside of the bag or the food inside it.
When I've used a Ziploc, or other plastic bag, and it is submersed into the bath, it collapses due to the air being pushed out by the water bath.
I believe whoever published that statement needs to take a course in refrigeration to understand how pressure works.
Somebody wiggles well, so the boss lets stupid ideas get out of the door.

My vacuum bags are much better suited to cooking in than any of the Ziploc or other baggies I've tried. They (baggie types) soften up to the point of distrust because of the heat.


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## daveomak (Nov 5, 2018)

I'm not sure but.......   In a collapsed bag, it's impossible to have a differential pressure compared to the outside of the bag...   A vacuum can only be created in a space..... 
Example.... when canning foods, a space is required in the top of the jar where the vacuum will form....
A jar that is full, it will not seal...  no vacuum...


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## atomicsmoke (Nov 5, 2018)

daveomak said:


> I'm not sure but.......   In a collapsed bag, it's impossible to have a differential pressure compared to the outside of the bag...   A vacuum can only be created in a space.....
> Example.... when canning foods, a space is required in the top of the jar where the vacuum will form....
> A jar that is full, it will not seal...  no vacuum...


I agree...hence my post. No pressure delta inside a soft enclosure.


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## atomicsmoke (Nov 5, 2018)

Holly2015 said:


> 5+ lbs of beef
> 32 ounce of broth
> 32 ounce of pepperoncini and juice
> 
> ...


Looks good. 

Did it boil? Lol


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## daveomak (Nov 5, 2018)

Geeeez Holly, That looks good...   What do you call it ????


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## zwiller (Nov 5, 2018)

Dumb question but I am basically a vac seal noob.  Do you just "seal" when using liquid like that?  Still seems like that would be hard to do.


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## chopsaw (Nov 5, 2018)

Had a freezer zip lock fail on me , lucky it was just corn on the cobb . So that was the last time . 

Holly was that eye round ? Never thought about slice and put back in . Great idea . I did this one last weekend ( chuck ) . The whole garlic cloves ate like candy .  No way would that be trusted to zip lock .


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## retfr8flyr (Nov 5, 2018)

Holly2015 said:


> Yep squeeze out as much air as possible and seal. If you try to vac the bag it’ll suck up liquid and make a mess.


If you have a chamber type sealer then you can seal liquids just fine. I know because I have one.


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