Caramelisation is a fascinating culinary process that can add depth and complexity to your favourite dishes, turning ordinary ingredients into rich, flavourful delights. But what happens to the sugar content of a dish during caramelisation?

Let’s explore how caramelisation works, why it's considered a chemical reaction, which foods can be caramelised and whether caramelisation affects sugar levels in specific dishes.

How does caramelisation work?

Caramelisation can occur when cooking foods containing sugars-natural or added. The browning and flavour development in various ingredients during cooking can be attributed to this complex chemical reaction. Here's how caramelisation works when cooking food.

Many foods like milk, fruits and vegetables contain natural sugars, such as lactose, fructose and glucose. When these sugars are heated, they can undergo caramelisation.

Cooking your food causes the natural sugars to lose moisture. As your food heats up, the water content evaporates, leaving the sugar molecules more concentrated and available for the caramelisation process. 

As these concentrated sugar molecules start to break down into simpler compounds through chemical reactions, this results in the formation of various flavour compounds and the characteristic browning effect seen in caramelised foods.

As the sugars break down and rearrange, new compounds are created, leading to the development of rich, complex flavours in your meals. These flavours can range from sweet and nutty to deep and savoury, depending on the food being cooked.

Is caramelisation a chemical reaction?

Yes. Caramelisation is indeed a chemical reaction, as it involves the rearrangement of sugar molecules to create new chemical compounds. The heat from cooking causes the sugar molecules to break down, leading to a series of reactions that result in the browning of your food and the release of a wide range of compounds. It's this complex chemistry that gives caramelised foods their characteristic taste and colour. Caramelisation is responsible for the crunchy caramel topping on crème brule and the golden-brown surface of muffins, cookies, cakes and pancakes.

What are some foods that can be caramelised? 

Sugar is the most common caramelised ingredient used in dessert-making, adding a rich and sweet flavour, but it’s a cooking technique that can be used on a variety of foods to enhance their flavour and taste. Some common foods that can be caramelised include:

• Onions: caramelised onions add a sweet, savoury and aromatic flavour to a wide range of dishes.
• Apples: caramelised apples are a healthy and delicious topping for desserts or a flavourful addition to savoury dishes.
• Carrots: caramelised carrots offer a natural sweetness and appealing colour.
• Capsicum: Caramelised capsicum has a sweeter and more complex flavour than raw capsicum.
• Meats: The Maillard reaction, which has many similarities to caramelisation, occurs when cooking meat, contributing to the browning and development of rich flavours.

Does caramelisation affect sugar levels in certain dishes?

The process of caramelisation involves breaking down and transforming sugar molecules within foods that naturally contain sugars. While this does result in the formation of new compounds, it doesn't increase the overall sugar content of a dish (unless you add sugar to help caramelise the dish).

In fact, caramelisation can reduce the perceived sweetness of a dish by breaking down simple sugars into more complex, less sweet compounds. Caramelisation tends to be more about creating a balance of flavours, enhancing the depth and complexity of your dishes and providing a rich colour to meals. The sugars involved in caramelisation – such as glucose and fructose, are typically already present in the ingredients used, and the process redistributes and transforms them into new compounds, ultimately adding to the overall flavour profile of your food without needing to add extra sugars.

Whilst caramelisation does not significantly increase the sugar content of a dish, it can greatly impact its overall flavour, making it a valuable tool in the kitchen for creating delicious and visually appealing meals.

References

McGee, H. (2004). On Food and Cooking: The Science and Lore of the Kitchen. Scribner.

Belitz, H. D., & Grosch, W. (2009). Food Chemistry (4th ed.). Springer.

Ziegler, G. R., & Kadzere, C. T. (2003). Caramelisation in foods and beverages. ACS Publications.

Monnier, V. M., & Baynes, J. W. (2005). The Maillard reaction in vivo. Chemistry and physics of lipids, 128(1), 19-48.

Hui, Y. H., Nip, W. K., Rogers, R. W., Young, O. A., & Lam-Chong, T. (2007). Food Biochemistry and Food Processing. Wiley-Blackwell.