On 6 March, we had an introduction to molecular gastronomy by Dr Linda Sellou. We went through the basic ideas behind chocolate and ice cream, and even tried our hand at making Chocolate Chantilly and Ribena Sorbet!
Ah– Chocolate. A dessert food that has one of the richest and most complex flavours of all. From McGee’s book, the flavours we taste from chocolate comes from the following: cacao bean (astringency and bitterness from phenolic compounds and theobromine); fermented pulp (fruit, wine, sherry and vinegar flavours from acids, esters, etc.); self-digested bean (almond, dairy and flowery notes from benzaldehyde, diacetyl and others); roasting and browning reactions (nutty, roasted, sweet notes); added sugar and vanilla (sweetness and warmth); added milk solids (caramel and butterscotch notes).
The kinds of chocolates vary widely, and we most commonly see milk and dark chocolate, with dark chocolate being my preferred choice! However, contrary to my preference, milk chocolate is the most popular form of chocolate. Milk solids and a large proportion of sugar make up most of milk chocolate, while cocoa solids and cocoa butter make up the rest. The low cocoa solids and high sugar content contribute to the sweetness of the milk chocolate. This is as opposed to dark chocolate, where its content is just cocoa solids, cocoa butter, significantly less sugar, and zero milk solids. The higher proportion of cocoa butter in chocolate also means it has a snappier texture than milk chocolate, which is comparatively much softer. Since dark chocolate contains a higher proportion of cocoa solids, the chocolate flavour is more intense, and is more bitter and astringent.
For the Chocolate Chantilly we made, we used a 72% cocoa chocolate, meaning it is 72% by weight cocoa butter and cocoa solids, and about 28% sugar.
We first broke up 100g of the chocolate into smaller pieces so that we could melt the chocolate more easily, then added it to a metal bowl. After which we poured in 85 mL of hot water, and proceeded to stir and mix to melt the chocolate.
Initially, I thought it was weird that we were told to add water to chocolate. I always imagined chocolate to separate from water because of the cocoa butter content, and that one should use milk to achieve a creamy chocolate mixture. On first look, the chocolate and water didn’t look like they belonged together. It was a clumpy mess and seemingly immiscible. However, with some patience and constant use of the spoon to further break down the chocolate pieces, we managed to get a smooth, glossy chocolate cream for the next step.
We transferred the bowl from the table to an ice-bath, where our aggressive whisking begun. Flashback Friday to Japanese Souffle Pancakes, haha!
As we whisked, we observed that the chocolate mixture started to become more viscous as it cooled down. Whisking the chocolate also incorporated air into the mixture, turning the mixture into a foam– which is gas dispersed in liquid. We were at first unsure of when to stop the whisking, but we observed and compared it with online pictures of mousse and decided that we achieved the right consistency.
Mmm! It was smooth, rich, and left us craving for more! So we used the rest of the chocolate bar to make a second batch of mousse, but that wasn’t as smooth sailing as our first attempt. Our second batch was slightly overmixed, so our mousse turned out slightly thick and grainy. As an attempt to troubleshoot, we added a little more hot water to the mixture and mixed. It loosened up and became smooth again, but when we whisked it over the ice-bath, the mixture did not thicken up as before despite many minutes of whisking. Upon reflection, I think we added too much water to the mix. Although the chocolate did become smooth, the water we added could be too much, making it difficult for the chocolate to stiffen effectively due to a lower melting point. Reading up on some information online, I learned that the best way to fix an overmixed mixture is to remelt the chocolate, then repeat the whisking process, instead of adding hot water. For our case, maybe we could’ve placed the bowl over a hot water bath as an easy fix. Also, we should’ve stopped whisking just before our desired consistency as the chocolate will thicken slightly upon sitting. Also, I learned that milk chocolates are not recommended for making this chocolate chantilly as its lower cacao content will give a runny soup, instead of a smooth mousse. However the versatility of this recipe allows for further experimentation, such as refrigerating the chantilly after it’s ready for its use in cake fillings, or even changing up the water to orange juice to make an orange chocolate mousse. I’ll definitely keep these changes in mind when making more chantilly at home!
Next, we made an easy Ribena Sorbet! So a difference between a sorbet and ice cream is this– sorbets are just fruit and sugar with no added dairy, while ice cream generally contains at least 10% milkfat, making ice creams creamy and sorbets not. But what makes sorbets smooth, nonetheless? Sorbets are smooth due to the rapid freezing process, as in our experiment where the ribena was quickly frozen using food grade dry ice.
The rate of freezing greatly affects the ice crystal size formed. The greater the rate, the smaller (more desired) the ice crystals formed. As such, some companies also use liquid nitrogen to achieve this rapid cooling process. Interestingly, sugar also plays a part in getting small ice crystals. Apart from providing sweetness, sugar also lowers the freezing point of the sorbet mixture, which is important as it reduces the risk of forming large ice crystals which will make sorbets turn out more like ice blended drinks instead.
The method of adding dry ice (or solid CO2 at -78.5 degrees C) not only makes the sorbet-making process a quick and easy one, but also adds texture to the end product. The dry ice sublimes, turning from solid to gas during the mixing process. This incorporates carbon dioxide gas into the mixture, which is no wonder why the sorbet was slightly fizzy when I tasted it! Also, the carbon dioxide gas in the sorbet reacts with the saliva on the surface of our tongues to give carbonic acid, which contributes to a slight tang of the sorbet.
Yet another interesting workshop to have amidst the week of mid-term examinations! It was both fun and enriching to learn more about the two tasty desserts, and I took home with me some good tips about mousse and ice cream making at home. I never knew that these desserts could be made with such simple steps, and it truly amazed me seeing the science at work in this workshop.
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