I got another blood test yesterday morning, and I went home feeling fine. Little did I know that it would set up a perfect excuse for me, 12 hours later... [That's another story...]
My mum always makes this soup for me after a blood test. It's basically sugar, water, jujube berries, peanuts, white wood ear, a longyan/lychee-type thing, and lotus seeds. It's actually quite delicious if you add milk to it. Anyway, on the way back, my mum and I were discussing the soup. She claims that we're supposed to use rock sugar to sweeten the soup, rather than plain old granulated or caster sugar, since it's "sweeter" to use rock sugar. Urban myth also claims that using rock sugar is better since it adds a ton more nutrients to the soup, since it "melts" slower. My mum also said that the caster sugar "disappears" when put in soup, so you have to use rock sugar since it "cooks for longer".
I am here to disprove these ideas. Scientifically speaking.
1. If you have a chunk of rock sugar, and you emulate that chunk with granulated sugar, you will not get the same "sweetness" of sugar. I mean, if you have a cube of rock sugar, and you have a sugar cube, even though the volume is the same, the moles of sucrose is evidently not the same. There is a ton of air between each granulated sugar crystal in the sugar cube, whereas in a chunk of rock sugar, there is less air in a sugar crystal, let alone between each sucrose molecule. In fact, if you were to weigh the cube of rock sugar, it should definitely be heavier than the granulated sugar cube. So, more sucrose means sweeter soup. Simple.
2. Rock sugar is sucrose. Granulated sugar is sucrose. "Organic Evaporated Cane Juice" is sucrose. Brown sugar is sucrose, with some molasses mixed in. Sure, there may be "trace" minerals and blah from the refinement and treatment processing from when the cane or beet juice was evaporated. It's all one glucose covalently bonded with one fructose. In water, a chunk of sucrose molecules dissolves into individual sucrose molecules. Even if there were trace nutrients, you'd have to eat kilos of that sucrose to perhaps obtain 1% of your daily intake of some nutrient...
3. Both caster sugar and rock sugar dissolve in water. They both stay dissolved in the water. Sucrose doesn't just "disappear". Both caster sugar and rock sugar don't "cook" at 90 or 100 degrees C. They just stay dissolved.
I like this soup though. I'm glad my mum bothers to dump everything in the slow cooker and leave it on overnight.