When I first saw the following video – which
is in Spanish – I wanted to share it with my friends. Even those who don’t speak Spanish.
So, in collaboration with Arcadi Garcia, who made the original, here is Gastrofisica in
English. Sugar – or, at least, refined sugar- is a
white, odorless, fine-grained material, which means that, in some ways, it behaves like
a liquid. Caramel, on the other hand, is… Uhhh… No. How does THIS turn into THIS?
Well, it can’t be that complicated, right?? You heat up the sugar, the sugar melts, and
then begins the process of caramelization, which is a hot, sweet, sticky mess of crazy
chemical shenanigans we’re not going to get into; first because we’d have to get
into too much chemistry, and second because you know WHAT? This whole caramel thing isn’t
as simple as it looks. First, we’ve got the chemical process of caramelization,
which isn’t very well understood. We know that it’s complex, that it creates HUNDREDS
of different compounds and that it involves LOADS of chemical reactions that, as I said,
we’re not going to get into, and anyway we don’t understand it anywhere near 100%.
And don’t get me started on melting sugar! ‘Cause I mean, in the first place, what
temperature does sugar even melt at? Different studies people have done on this
don’t agree. Some say this temperature. Some say that temperature. In the end, it all seems
to hang on whether to reach this or that temperature you heat up the sugar fast or slow. Except
the whole delightful concept of “melting point” is precisely that, at the same pressure and
so on, the temperature at which something melts will always be the same, no matter how
you got there! The point of temperature is to give us an
idea of how much kinetic energy the molecules of a given substance have; how fast they move.
In order to melt, the molecules in a solid need, at the very least, a certain amount
of energy to break free from their neighbors, and that energy depends on the substance they
belong to. Like, at atmospheric pressure, water always melts at 0ºC, gallium at about
30ºC which is why it melts in your hand, iron melts at around 1500ºC and sugar, apparently,
WHENEVER THE HECK IT FEELS LIKE IT. But if sugar – or, in other words, sucrose
– melts, like, whenever it gets around to melting, that’s because it doesn’t actually
melt: before getting to that point, it breaks into its components: glucose and fructose.
Glucose and fructose, which are more stable, DO have real, proper melting points, and DO
melt the way we think of when we think of things melting, and they’re what you see when
sugar “melts” (you can’t… you can’t see me, but I’m making some crazy air quotes over
here). Most recipes for making caramel talk about
heating your oven up to 160ºC-180ºC [320°F – 355°F]. And if you want to make it in a
pot or whatever (like we’re doing in this video), you can get things up to more or less
that same temperature. But to simply break sucrose into glucose and fructose, we don’t
need that much heat! That is, if we control our excitement and instead keep the temperature
around 150ºC [300°F] but for a longer time, we can make caramel without having to melt
anything: it just goes directly from solid to solid! To give this a shot, we tried to dry-caramelize
some sugar cubes. With the oven set to 150ºC[300°F], after 3 and a half hours look at these beauties!
I mean, how sweet are these? Perfectly caramelized sugar cubes without melting a single thing!
They’re sugar cubes, except, you know, caramel sugar cubes. They taste like caramel, they
smell like caramel, they ARE caramel. In the form of a sugar cube. And yup, we were able
to do all of this just because we tried to understand the physics of caramel. Delicious,