Nanogirl Michelle Dickinson: Bursts of flavour

Bursting bubbles release the sweet smell and flavour of champagne. Photo / 123RF

As you raise a glass this Christmas, stop and take a look at the bubbles in your Champagne – they might tell you more about your drink than you think.

The amount of fizz or effervescence in your sparkling wine is actually really important to its taste, aroma and mouthfeel.

It used to be thought that a long, steady stream of bubbles in a glass of champagne was the easiest way to detect the quality of the drink. However, researchers have found that the size of the bubbles is also important to the taste of the champagne.

Wine bloggers have often cited that a glass of champagne releases 15 million bubbles, but scientist Gérard Liger-Belair found the number to be much lower at only 1 million bubbles a glass.

Using high-speed photography, he was able to show that when champagne bubbles rise to the top they form a regular hexagonal pattern on the surface. They interact with other bubbles and throw up hundreds of tiny droplets when they burst.

A big part of how we taste food and drink is by its smell. The aromatic compounds which give champagne its unique sweet smell and flavour are all carried up through the bubbles and these bursting droplets fill our nostrils when we place the drink close to our lips.

The research published in the European Physical Journal found that bubbles in Champagne vary from 0.4mm to 4mm across. The perfect bubble size was determined to be the one to release the largest number of droplets when it burst, which in this study was a 1.7mm-radius bubble.

It's not just bubbles that are important in champagne, the viscosity, or how well the fluid flows, is also critical to its taste.

Additives in champagne can increase the viscosity, which reduces the number of droplets released at the surface. Ideally, the champagne should be free-flowing and as water-like as possible in its consistency to help catapult the flavour-filled droplets from the bursting process.

Temperature is another important factor for champagne lovers with colder champagne having a better perceived taste. This is because colder champagne carries less alcohol in each bubble which can overpower the delicate flavours in the champagne.

The temperature is also important from a health and safety point of view. Champagne bottles which were cooled to 4C were shown to release their corks more slowly potentially reducing the risk of flying cork accidents.

When you open your champagne bottle and the cork pops off, take a look for a small cloud at the bottleneck. As the pressure inside the bottle is five times more than the atmosphere, the gas in the bottle suddenly expands from this pressure change and pushes the cork out at high speed.

The cloud that appears is due to the carbon dioxide cooling and condensing the water in the air which forms into a mini cloud around the top of the bottle.

Finally, for the perfect glass of champagne, you will need the perfect champagne glass.

A clean glass is essential, as bubbles will form on any dirt or grime on the walls of the glass. A tall, thin flute delivers lots of flavour very quickly and spits the fizz upwards, which is good for young, light champagne.

However, older champagnes should be served in a white wine glass which traps both the small slower rising bubbles and the large faster-rising bubbles in the same space at the top of the glass allowing both bubbles to deliver their aromas and the complex flavours of the champagne to be enjoyed.