Physics/politics behind pressurized plastic ketchup bottle?

[Tallbald]

Applying ketchup to my scrambled eggs this morning it hit me.
So it's always annoyed me that if I turn an almost empty plastic ketchup bottle with a flip top lid upside down to store in the frig door, unless I'm very quick next time to get it to the table, open and use it, that last of the ketchup blasts out under pressure from the bottle all over my fingers or plate. I pondered on this and decided it must be a perfect example of gas expansion (PV=nRT?) with application of heat. The temp gradient between the frig and the room temp of the kitchen table is apparently plenty enough to cause the air in the bottle above the last few tablespoons of ketchup to expand and turn the ketchup bottle into basically an aerosol spray container. All over my fingers. And shirt.
There should be laws mandating check valves in all plastic ketchup bottles. It's "for the children", and makes as much sense as turning restaurant servers into criminals if they give a patron a straw without a request (a proposed California law---punishment of $1000 and jail time). After all. The pressurized ketchup bottle leads to my use of more napkins than would otherwise be necessary. That creates more paper in the landfill. That MUST lead to global warming somehow.
Additionally, should I decide against risking the ketchup spray and throw out the mostly empty bottle instead, I'm wasting food which cheats third world nations and leads to accusations of first world conspicuous consumption.
I can't win for losing.
Just a thought. Interesting times. Don.

 

[Ale-8(1)]

Ketchup on eggs?? Wow, that's a subject for another thread altogether. :wink: :wink: :wink:

But I hear ya, and good analysis of the situation. Same thing goes for "squeeze butter" and anything else in the plastic bottles. I just try to aim the bottle at the food before popping open the lid.

And my wife saves the empty bottles for her homemade green pepper sauce . . . which is REALLY good on eggs. :mrgreen: :shock: :mrgreen:

 

[Tallbald]

Ummmmmm... homemade green pepper sauce..... ummm. Oh. Ketchup on my scrambled eggs (and omelets) was a mid-life crisis I think. I started at 40. Don.

 

[Conservative]

I'll try almost anything, so I'll try ketchup on eggs. Maybe I'm missing out....

At time though, I'm a purist.

I love eggs in their every form from simply fried over medium to scrambled and find the additive I want is salt and pepper. Their taste without much addition is great all by it's lonesome...for me.

Ketchup goes a long way for me and I've only (in small doses) ever applied it to em ole french fried pertaters...

 

[sfhogman]

I'll have to check to see if Sriracha does the same thing...

 

[JFB]

I started doing the math to show the quainity of Ketchup that would spurt out,
(frig of 36F and room of 70F a 20oz bottle would spurt out 1.4 ozs)
BUT something didn't make sense
I would assume the last time you use the ketchup, the bottle was at room temp when you closed the lid.
Then you put it in the frig to cool down and cause a vacuum to be created in the bottle.

THUS, I think you are being harrassed...
Someone is going into the frig at night, while the ketchup is still in the frig, opening the lid to let it suck in cold air then closing the lid just so it will spurt you the next morning!

the tidbit I caught and had to google and in disbelief is the CA straw ban law. while a law is overkill, I do wish take out folks would head my request when I tell them I don't want pastic-ware

In case anyone cares
the increase in pressure for the above temp increase would be 14.7 X (70+460)/(36+460) -14.7 = 1 psi
the volume change to relieve that pressure would be 20 X (P2/14.7) - 20 = 1.4 oz

 

[Tallbald]

JFB I appreciate the math. AND. I had not considered the possibility of nightly cold ketchup lid flippers. We have a security system but obviously someone or something (an inside job?) may be ketchup lid tampering. Our Boxer, Ms. Ruger has long been a creative scrounger, first noted after we adopted her, when she "secured" a 3 pound block of thawing burger from the counter top. I'll borrow a game trail camera and hope I remember it when I, in my underwear, raid the frig late at night. Uh oh. Something else... some other cause....might be afoot.... Don

 

[Pat-inCO]

OR . . . you could just maintain the pressure on the sides during your
previous use, and snap the top on.

 

[Wyandot Jim]

Let me add this tidbit of information on the nasty ketchup bottle and many of their friend's tricks. I know for a fact when you leave the 130' elevation of Texas and go to the 10,000' elevation of Colorado some REAL ugly tricks are played on you by those nasty bottles.

 

[Jeepnik]

Ah, but what JFB forgot is that the lid on a ketchup bottle isn't an air tight seal. And as the air in the bottle contracts as the temperature lowers, the reduced pressure created will draw air in past the lid, thus equalizing the pressure in the bottle with the pressure in the refrigerator.

So, you can relax and know that no one is sneaking into the frig at night and flipping your lid.

By the way, I just lay the bottle on it's side and give it a stiff shake to get the last bit to the opening before I use it.

 

[bogus bill]

Years ago I was in a restaurant and slapped the bottom of a glass ketchup bottle and it broke in two as slick as if you cut it with a knife.
We moved here to Utah at 6,000 feet. Always on a certain stretch of road coming back from St. George, 2,500 feet, a stone would hit the windshield without fail. The windshield never cracked. We commented on it many times. The wife ALWAYS carries a bottle of water. Then it dawned on her the noise was the bottle of water ALWAYS cracked in the same stretch.

 

[Tallbald]

I haven't had a physics or chemistry course in 35 years. This is is overwhelming in its complexity. Don.

 

[Ale-8(1)]

Ah, but what JFB forgot is that the lid on a ketchup bottle isn't an air tight seal. And as the air in the bottle contracts as the temperature lowers, the reduced pressure created will draw air in past the lid, thus equalizing the pressure in the bottle with the pressure in the refrigerator..

But just like with home pressure canning, if the lid is a decent fit the reduced pressure within the bottle will "suck" the lid on tighter, resulting in the "whiff" when you open it of outside air rushing into the bottle to replace the vacuum.

(Yes, I know, there is no "suck" . . . just the relative difference between the inner and outer pressures)

:mrgreen: :wink: :mrgreen:

 

[Rick Courtright]

Hi,

Using my theory of creationary evolution (the idea that God made the important stuff first, then left us to screw up the rest), we should remember ketchup was packaged in glass bottles for decades. They were stored lid up, and this "exploding ketchup" problem was never seen. On top of that, there was always the "shaking and talking to the bottle" regimen once the level of the ketchup got down there, trying to get more out! The ladies working in the diners and coffee shops had a skill today's "Do you want fries with that?" crowd probably can't even comprehend, too. Remember the series of two ketchup bottles on an empty section of the counter, one right side up, the other balanced upside down to drain the remaining sauce into the bottom bottle? Try that with one of those little packets...

Then some impatient fool came along and figured ketchup should be packaged in plastic bottles and stored upside down so it will come out faster, and guess what? Fooling with Mother Nature will get you every time!

Rick C

 

[rugnelli]

Yes, ketchup on scrambled eggs!

To reduce ketchup "blooping" when trying to get the last of it out of the container when stored cap down, try this... Pick it up with your fingers and thumb across the widest cross section (short sides) and squeeze to get the other walls to bow out causing a vacuum effect inside the container. Open the lid and when ready for ketchup, relax your grip. If additional ketchup is desired, squeeze the long sides (short cross section) to squeeze it out.

Also, ketchup is a great dip for Original Pringles potato chips. Or better yet, put a dab of ketchup on a Pringle and put another one on top for a Pringle & ketchup sandwich.

 

[Rancher Will]

Reminds me of a poem that I still remember taught by my Grade School teacher.

Pound and shake
the Ketchup bottle
First none will come
And then a lottle

 

[Ale-8(1)]

Ketchup is a Non-Newtonian fluid, and as such has unique properties.

https://en.wikipedia.org/wiki/Non-Newtonian_fluid

"In a Newtonian fluid, the relation between the shear stress and the shear rate is linear, passing through the origin, the constant of proportionality being the coefficient of viscosity. In a non-Newtonian fluid, the relation between the shear stress and the shear rate is different. The fluid can even exhibit time-dependent viscosity. Therefore, a constant coefficient of viscosity cannot be defined."

"Ketchup is a shear thinning fluid. Shear thinning means that the fluid viscosity decreases with increasing shear stress. In other words, fluid motion is initially difficult at slow rates of deformation, but will flow more freely at high rates."

You're really messing with Mother Nature with that stuff. It's difficult to start moving, but once started it really pours.

:shock: :wink: :shock:

 

[exavid]

I hate squeeze bottles of just about anything. It's hell on arthritic thumbs.

 

[Taterman]

I started doing the math to show the quainity of Ketchup that would spurt out,
(frig of 36F and room of 70F a 20oz bottle would spurt out 1.4 ozs)
BUT something didn't make sense
I would assume the last time you use the ketchup, the bottle was at room temp when you closed the lid.
Then you put it in the frig to cool down and cause a vacuum to be created in the bottle.

THUS, I think you are being harrassed...
Someone is going into the frig at night, while the ketchup is still in the frig, opening the lid to let it suck in cold air then closing the lid just so it will spurt you the next morning!

the tidbit I caught and had to google and in disbelief is the CA straw ban law. while a law is overkill, I do wish take out folks would head my request when I tell them I don't want pastic-ware

In case anyone cares
the increase in pressure for the above temp increase would be 14.7 X (70+460)/(36+460) -14.7 = 1 psi
the volume change to relieve that pressure would be 20 X (P2/14.7) - 20 = 1.4 oz

 

[Ka6otm]

Ketchup on eggs? I've seen Canadians do it, but civilized people use Tabasco sauce.