When Did They Start Making Ketchup Bottles Upside Down?

Ever since I was little, getting ketchup in a bottle to start flowing has been an inexact, messy process.

I learned about a number of techniques over the years.

A bottle of Heinz ketchup

A bottle of Heinz ketchup (Photo credit: Wikipedia)

You can tip the bottle upside down and smack it hard on the bottom a couple of times.

First, you will see a little dribble of ketchup juice.

Then, when you give it a couple more smacks, it suddenly releases and glops all over your French fries, hamburger, plate and lap.

You can stick a knife into the neck and try to release the ketchup in the neck, while tapping it near the bottom and holding it at an angle.

Apparently, David Letterman came up with the idea of swinging the bottle in a wide arc, once, and that gets it started.

Physicists say you can apply Newton’s First Law of Motion, that an object at rest or moving will continue until something gets in its way.

For ketchup this means holding the bottle at a 45-degree angle, hitting the bottom and letting the curved neck of the bottle hit your other hand.

The idea is that the bottle will stop when it hits your other hand, but, given enough force, the ketchup inside the bottle will keep moving.

This is probably the same principle that makes the David Letterman swinging it in an arc motion work.

You get the momentum of the ketchup inside the bottle moving and then stop the bottle.

And, finally, just whack it on the 57 label while holding it at an angle to get it started moving and leave room for air to help keep it flowing.

The common saying for most of my adult life was, “We can send a man to the moon, but we can’t make a ketchup bottle that works.”

Until now.

What Are the Physics Behind the Reluctant Ketchup Bottle?

There are a couple of things going on to keep ketchup inside its bottle until it explodes all over your hamburger.

One is shear thinning, the property of a liquid to flow when it is thin and not to when it is thick.

When ketchup is at the neck of a full bottle, it is thick. Once it starts flowing, after you have it started, it has room to thin out and flow more easily.

Whipped cream, blood and nail polish share this property.

Another property of ketchup is thixotropy.

Thixotropy is the characteristic of fluids that are thick like a gel in their normal state but thin out when agitated. This is what happens when you shake  the ketchup bottle.

Wet cement and paint in a can also share this property.

There is also a problem just getting enough air through the neck of the ketchup bottle to the bottom to help push the ketchup out.

To do it, you have to encourage spontaneous symmetry breaking.

Imagine you hold the bottle exactly upside down. The ketchup could flow out of any side of the open circle on the neck of the bottle.

But, because it is thick and doesn’t have enough air pressure behind it to start the flow, it doesn’t.

Then, you tip the bottle, encouraging the ketchup to flow out of one side of the opening.

This tips the balance from an equal, or symmetric chance that the ketchup will flow out of any side, to encouraging it to flow out of one side of the opening.

This is probably why whacking the bottle on the 57 label while holding it at an angle works.

How Did the Upside Down Bottle Solve All These Problems?

It started with the invention of a valve in 1991 in Midland, Michigan.

Paul Brown was trying to invent a valve for a shampoo bottle, so it could sit on the edge of a tub, upside down, and dispense shampoo without dripping.

The shampoo maker bought it, as did a baby food manufacturer for sippy cups and NASA for astronauts to drink in space.

Heinz introduced the upside down squeeze bottle, with this revolutionary valve, in 2002.

And, they discovered, like the shopping cart inventor that came before them, if customers had bigger bottles of ketchup, they would eat more.

78% more when the bottle size was increased from 24 ounces to 46 ounces.

Now, we can send a man to the moon, and he drinks from the same valve that lets us pour ketchup without getting it all over the table.

Thanks, Paul Brown.

What is your favorite way to get ketchup out of a new bottle?

Do you use upside-down bottles?

What else could we pour upside down?

To you and discovering how the world works with your grandchildren.


Carol Covin, Granny-Guru

Author, “Who Gets to Name Grandma? The Wisdom of Mothers and Grandmothers

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