If you’ve ever wondered why Asian stir fried sauces are smooth, sticky and clear, the answer is starch.
The best starch for Asian cooking is arrowroot starch. The problem is that it is so hard to find. Industry rumor has it too that commercially sold arrowroot starch is often mixed with the less expensive potato starch.

Can’t find arrowroot starch? The next best thing is tapioca starch. Depending on your location in the world, it may be labeled as cassava powder or even cassava flour.
What makes tapioca starch so unique? The texture it gives sauces, for one. Corn starch may thicken a sauce but it won’t give the sauce that glossy appearance and sticky texture that makes Chinese stir fries so good.
For frying, when tapioca starch is used to coat the meat, even after the meat is tossed in sauce, the crispy crust of the meat is retained and does not get soggy for hours. It may have to do with the fact that tapioca starch does not contain gluten.
Next to tapioca starch (just in case it isn’t available), what else is good? Potato starch is almost as good as tapioca starch. Corn starch would be a far third.
What about flour? Flour is not a good substitute. Flour results in a cloudy rather than a clear sauce. Meat dipped in flour-based batter turns soggy within minutes after frying.
So, when cooking Asian, think starch, not flour.