Authentic sweet potato flour turns white when burned.

After the real sweet potato flour is burned with fire, the vermicelli will expand rapidly and turn white. The powder breaks into pieces as soon as you twist it, without any residue, and it burns fully. If the powder is black when you twist it on your hands after burning, and it will burn directly, and there is a dark residue, it is probably because gelatin has been added.

The longer the authentic sweet potato flour is soaked, the longer it takes to cook.

When soaking real sweet potato flour, the more it is soaked, the more it is soaked. After soaking a small handful, it will be enough for a large bowl. This is The biggest difference from vermicelli made from other starches is that it takes a long time to soak. It takes 2 or 3 hours to soak in cold water before it can be soaked. After soaking, it feels smooth and elastic. Even if you use hot water, it will take more than ten minutes. Only when it is soaked can it be cooked for a long time without being mushy and still chewy.

As for the fake sweet potato starch, it is ready just by soaking it in cold water. After it is soaked, it has no elasticity and is not smooth enough. It will become mushy after being cooked for a long time, and it will break with the chopsticks.