While this dessert may look quite simple, achieving that smooth, spherical shape and perfect transparency all the way through is a feat of culinary talent made possible with the use of one particular ingredient: agar agar.
Agar agar is a type of vegan gelatin that is made from seaweed and functions as a thickening or stabilizing agent in a wide range of dishes. The recipe for raindrop cake calls for just two ingredients: agar agar and water.
Despite the brevity of the ingredient list, the execution of this dish is no easy task. Only a small amount of agar agar is needed — the cake will be ruined if the quantity of this one component is slightly off; too much of the gelling agent and the cake will overly firm and become cloudy, rather than transparent; too little and its bubble-like form won’t hold.
The raindrop cake originated in Japan where it is known as mizu shingen mochi. It was invented by a confectionary company called Kinseiken Daigahara in 2014 and was immediately sought after by locals and foreigners alike, who could only find it in the small town of Hokuto until two years later when it started popping up on menus around the world. Besides the one-of-a-kind beauty of this dessert, there is also something alluring about the fact that it is quick to disappear — outside of a refrigerator, the agar agar will only maintain its curved shape for about a half hour.
When it comes to flavor, however, there is not much to recommend this raindrop lookalike, which is different from most baked goods that we’d call cake. Since the mizu shingen mochi is as flavorless as water, it is generally served with some kind of sweet accompaniment, such as sliced fresh fruit, roasted soy powder, or black sugar syrup known as kuromitsu, a heavy drizzle made with brown sugar and water.
The raindrop cake wouldn’t exist without agar agar. This odorless, tasteless, gelatinous substance is extracted from a specific kind of seaweed — red algae — and can be sold in various forms, including strands, powders, flakes, and bars. While many kinds of gelatin are made from animal byproducts, agar agar is a more inclusive alternative since it can also be consumed by those who follow a vegan diet.
To make the most of the sticky quality of agar agar to prepare a perfect raindrop cake, this ingredient must be completely dissolved in boiling water, then poured into a mold and left to set up in the fridge overnight. A similar technique can be used for other desserts, such as panna cotta or jelly candies. Elsewhere in Asia, you can find agar agar in the ultimate Cantonese comfort food, almond Jell-O and fruit cocktail. It can also be found closer to the raindrop cake’s place of origin in Japan’s capital where it takes the playful, savory form of soy sauce dots on hypnotizing Takazawa sashimi. This versatile ingredient can even be used in the process of clarifying citrus cocktails.
