Have you ever wondered why in the world Heinz would sell ketchup in a glass bottle when it’s so impossible to get the ketchup out of there? I’m sure we’ve all been there, sitting in a restaurant, mouth watering over a plate of burger and fries, ready to dig in to a tasty, calorie injected mean, and hopelessly foiled in our conquest by a glass bottle from which the ketchup simply will not flow. I’ve seen people beat the bottle with a knife or slap it around a bit with an open palm, I’ve even heard the “hit the 57” secret, as if ketchup is really a magical object to which you must simply speak parseltongue to gain access.
As usual, it seems that what has been chalked up to magic, luck, or poor product packaging actually comes down to science. Ketchup (or in South Africa, tomato sauce) is a mixture of tomato, sugar, salt, and water. I’ve you’ve ever cleaned out your fridge after a power outage or taken a chemistry class, you’ll know that as a result of different densities, these four ingredients tend to separate, particularly when left out on grocery store shelves. Food scientists use hydrocholloids, compounds that act as gels or thickeners in food products, to prevent this separation. Hydrocholloids tend to be the most unrecognizable ingredient on a food label; Xanthan gum, locust bean gum, gum arabic, pectin, sodium alginate, etc., and are obtained in a variety of different ways, from seeds, plants, animals, even bacteria.
Hydrocholloids are relevant to glass bottle ketchup because hydrocholloids display pseudoelestic behavior. Unlike water (which displays Newtonian behavior), when you stir a hydrocholloid in solution, it becomes easier to stir the longer you stir it. Think of canned cake frosting. When you first take the lid off, you have a solid block of frosting, but give it a little stir and you have a softer, spreadable, and delicious cake topping. Because of it’s pseudoelastic behavior, ketchup reacts much like frosting, it is firmly sealed in a gelled chemical structure until agitated.
So what’s the easiest way to get ketchup out of a glass ketchup bottle? Simply shake it with the lid on to break down the gel network, and it’ll pour out very smoothly. No magic involved, just science.
Clearly, I’ve learned a lot of random things in my food science class. The classes I’ve had the opportunity to take in South Africa have been completely outside the realm of what I would have taken at Georgetown, and it has made me realize how much foundational knowledge about the world is either assumed that we have or assumed to be irrelevant or insignificant. But whether I’m learning about what’s really in lunch meat or how margarine is made or how the Internet, the physical thing, really works, these all seem extremely relevant, maybe not to a future job, but in shaping the way I understand the world.
Particularly in the case of food science, where we as American’s are constantly being bullied into thinking that this chemical or process will inevitably lead to our imminent demise and thus we must buy into this new lifestyle to save ourselves, I wonder how much taking an Intro to Food Science class might help us be more critical of marketing, more discerning about our food choices, and happier overall. American culture has no traditional cuisine to fall back on (as most places in the world do i.e. Rice and fish based diet in Japan), but as American’s, our access to science and other resources is unmatched. Ifwe took a little more time to learn the basics of how we live and how the technology around us works, imagine how much less frustration there would be waiting for ketchup.
Butt Naked Travels 