Molecular gastronomy, as gastro would suggest would be something to do with your stomach…and I would think immediately of food! Molecular gastronomy is the study of food and culture, analyzing it down to the molecular level. It proves to be interesting as it can explain certain food phenomena eg. how and why a certain ingredient such as an egg can be treated in so many ways (under vacuum, frying, whisked). Chemical and physical transformations are accounted for the many chemical compounds that make it what it is. It is definitely difficult to predict what happens to all of these compounds under a certain condition but that is what makes food interesting….right?
This week we attempted mousse, with its name came from french, which means “froth” or “foam”. We whisked melted chocolate and the air within the matrix holds the structure up. When over-whisked, the structure is broken down by mechanical forces and the mousse would be likely to have a sandy structure. If under-whisked, insufficient air is introduced into the structure and appears to be “flat”, and tasted heavy on the tongue. Our mousse should be whisked into medium peaks, roughly 2/3 stiff, where it is solid enough to give texture but still workable.
As an experiment, different brands of chocolate were used. There were some of 70%, 90% and 99% cocoa. Due to the amount of cocoa butter in the chocolate, some groups did not get the mousse consistency and tasted rather bitter or sour. Our group was fortunate to have picked the Whittakers chocolate (shown in the picture above) which was a good balance of bitter and sweet. Other brands that were experimented on was Valrhona, cadbury, etc.
Using 100 grams of chocolate, we added 80 grams of hot water, then stirred and melted the chocolates until there were no chunks left. We then placed the bowl on ice, and whisked it to introduce air. The motion of whisking and frequency was important.
After succeeding the first time, we were excited to create another batch. However, it wasn’t that easy. The number of factors surrounding mousse making are many and the second attempt failed to produce the same results. This was a good failure as we realized that mousse making isn’t that simple and reflected on the difference in our procedures or quantity of ingredients added. The only thing we knew was that we added extra water and tried to whisk it up again as the mousse was slightly rigid/hard. Sad to say but we didn’t manage to identify which step was the major factor that resulted in the failed attempt.
The cocoa butter content is very important for the fluidity and is measured in drops symbol system from 1 to 5. The higher the number, the more cocoa butter it contains and hence the more fluid the chocolate is. Based on online resources, it says that three-drop chocolate has exactly the right amount of cocoa butter in it and is extremely versatile, perfect for any kind of application.
The next part was the sorbet, and a dessert that contains no milk, eggs, or cream. It is purely made of water and fruit puree. Since it only has this few ingredients, it is much lower in calories and fat as compared to our regular ice cream.
In a usual sorbet concoction, fruit puree, water and sugar syrup are mixed together. In this workshop however, we used ribena concentrate. Water was added to the ribena to dilute it, and we simply poured this drink into the metal bowl and added dry ice. Some of you may not know it but dry ice has nothing to do with ice, but only functions like it. It is actually solid CO2 that sublimes at room temperature. Commercially, ice cream can be made using liquid nitrogen, which boils at –196 °C. Doing this at room temperature of 25°C is way above the boiling point and hence ice cream (made of heavy cream and sugar) freezes almost immediately once in contact with nitrogen. This reduces the temperature of ice cream drastically and the drop in temperature slows down the motion of all the molecules. Here on, water molecules begin to form small seed crystals and nucleation sites. In nitrogen ice cream, the particles sizes are smaller than 20 micrometer, the minimum size for our taste buds to detect.
(insert science for formation of small ice crystals and creamy texture)
This rapid freezing prevents crystals above 100mm from developing and creates more seed crystals. Creamier ice creams are made of minute crystals of 10-20 micrometer, and is done by two methods: either churning slowly or frozen quickly. If done correctly, it would successfully form fine textured tiny ice crystals within the sorbet, producing a smooth consistency.
However, since there is dissolved CO2 in the sorbet, it gives a tart feeling or biting sensation when the sorbet touches your tongue, similar to drinking a soda.
Watching the pasar malam (translates to night market in english) uncle work on a cold metal surface creating ice cream rolls inspired us to try it as well. We smoothened out the sorbet on the metal bowl (as shown in picture) but it did not rolled up nicely.
One last point! Be extra careful when using dry ice (if you decide to buy it and have an ice cream party at home) as prolonged contact can freeze your cells and cause frostbites that have a sensation similar to burns, and be careful to thoroughly mix your sorbet to ensure there are no chunks of dry ice left before consumption.
Whisk away! 🙂