What do you think of when you hear the word “caramel”? Do you think of the Salted Caramel Mocha from Starbucks or the chocolate bar Caramilk? It’s incredible how many variations of caramel there are available to us. I remember when I was a kid, caramel only meant one thing: Werther’s Original. I loved unwrapping the yellow foil and sucking on the caramel until my mouth was numb.
But what exactly is caramel and where does it get it’s distinct colour and flavour from?
Turns out caramel is made from sugar that has undergone a process known as “caramelization”. Caramelization uses heat to remove water and breakdown sugar to give caramel it’s nutty flavour and brown appearance. The type of caramel depends on the sugar used. When we think of sugar we usually refer to table sugar which is made of sucrose however there are other types of sugar caramel can be made from like honey that consists of mostly fructose. The type of sugar is important because different sugars have different caramelization temperatures. For instance, fructose’s caramelization temperature is 110 degree Celsius while sucrose is 160 degree Celsius. Therefore honey will create a darker looking caramel than table sugar.
To keep things simple, let’s explore the caramelization reaction of table sugar. As the sugar is heated, it begins to boil and decompose. But how can sugar decompose? Well, sucrose is actually a type of “disaccharide” which is a fancy word scientists use to call two “monosaccharides” or 2 simple sugars joined together. The 3 simple sugars are “fructose”, “glucose” and “galactose”. So when we say sucrose “decomposes”, the two sugars units that were previously joined together separate, creating fructose and glucose. Afterwards, a condensation reaction occurs. This means the sugar units combine and form a larger molecule losing water in the process. Other reactions like isomerisation (rearrangement of atoms in a molecule) and dehydration (loss of a water molecule) follow. The ones we are more concerned with are the fragmentation (when a molecule is broken into smaller parts) and polymerization (adding more sugar units to a molecule) reactions because fragmentation produces the flavour and polymerization produces the colour of caramel.
So wait… caramel is just sugar and heat? Not so fast. There are stages of caramelization and depending on how you want to use the caramel will determine the time and temperature you heat the sugar at. For example, stage 5 is called “large ball”. It is table sugar heated at 119 degrees which is suitable for making soft caramels. On the other hand, stage 7 is called “hard crack” which is sugar heated at 165 degrees to make hard candies like Werther’s Original”. If you are not careful enough and you heat the sugar too long to “Black Jack”, the sugar breaks down into pure carbon giving you a burnt flavour.
If candies don’t appeal to you, the same concepts we’ve discussed can be applied to vegetables. Most of you have probably tried caramelized onions or carrots and personally I love caramelized onions on my burgers. Caramelization is possible because carrots and onions have a high sugar content.