How to get ketchup from a bottle without the wait, watery goo and splatter
Some foods have stirred important questions: Where’s the beef? Got milk? How many licks does it take to get to the Tootsie Roll centre of a Tootsie Pop?
And: What is the most effective way to get ketchup from a glass bottle?
Thanks to an Australian researcher, Anthony Stickland, there are good answers to that last question.
Stickland, a senior lecturer at the department of chemical and biomolecular engineering at the University of Melbourne in Australia, has come up with step-by-step instructions that should help your ketchup go with the flow. But first, some science. Common liquids, such as water, alcohol and oil, respond to force linearly. That is, if you apply twice the amount of force, they move twice as fast, a theory put forth by Sir Isaac Newton.
But “non-Newtonian” liquids like blood, mayonnaise, paint and peanut butter do not respond that way.
Their thickness changes depending on how hard, fast or long you apply force, according to a TED-Ed video.
From a physics perspective, “ketchup is one of the more complicated mixtures out there,” the video says, adding that it cannot seem to make up its mind whether it is a solid or a liquid.
Ketchup will generally behave as a solid. But if a certain amount of force is used, it will
abruptly become thinner, causing it to splatter all over your hamburger. (Cue sad trombone.)
According to the NPD Group, a consumer research firm, 93 per cent of U.S. households keep ketchup on hand.
That’s a lot of bottles in need of proper handling.
Enter Stickland, who customarily works with wastewater treatment sludge in the field of rheology, the study of soft solids.
Here are the three steps he recommends:
1. Shake the bottle (with the cap on)
“You need to overcome the yield stress to mix it, so it needs a decent oomph,” he said in a university statement. “Briefly invoke your inner paint shaker.”
Solid particles in the ketchup may have segregated or settled, so the goal of shaking the bottle is to re-homogenize the particles evenly. This should help prevent a watery mix, which may have gathered at the top, from pouring out.
2. Turn the bottle upside down You can dislodge the ketchup with a “strong whack” — this can be done multiple times, but once should be enough — or thrust the bottle downward at high speeds.
“Swiftly stopping the bottle should slump the sauce into the neck,” he said, referring to “tomato sauce,” the Australian term for what we call ketchup.
3. Remove the cap, tilt and pour
This is where things can get a little tricky. First, remove the cap.
“The brave can do it upside down, but I would normally turn it upright, but carefully so as not to send the sauce back into the body of the bottle,” said Stickland, who in an email noted that he drew on his knowledge of rheology and had not done any experiments to solve this condiment conundrum.
Tilt the bottle until the ketchup flows. If it doesn’t, gradually increase the force with a shake or a tap.
“The amount of force depends on how much is left in the bottle,” he noted. “A full bottle will have the weight of the sauce pushing down whenever the bottle is tilted, whereas a nearly empty bottle will need some help.”
Hold the bottle at an angle of around 45 degrees with one hand around the neck while delivering firm taps on the bottom with the other hand.
What about poking a knife into the bottle?
“Sticking a knife in will stir it locally” and decrease the viscosity at the opening of the bottle, Stickland said in an email. “So, a knife will get some of the sauce in the opening to flow, which may be enough.”
Heinz promoted its slow-moving ketchup to the tune of Carly Simon’s “Anticipation” in a 1970s commercial.
To release the ketchup faster from a glass bottle, the company recommends applying a “firm tap to the sweet spot on the neck of the bottle” at the site of the “57” label. That is one way to apply force to get the ketchup moving, Stickland wrote, adding, “However, I think this is just marketing.”
Newton’s laws of motion always hold, he said, so any way to induce acceleration through tilting, whacking or shaking should work.
Or, you could take one other piece of his advice: “I always go for the squeeze bottle.”
Most of us have ketchup on hand and sometimes it is challenging to pour it without getting that watery splatter.