Purchase corn flour from the baking aisle of a supermarket. Note that in some countries it is called cornstarch instead of corn flour. The mixture should resemble a sauce. If it is thick and lumpy, simply add more water.
Leave the sauce on the stovetop while you stir it. If the sauce is sticking to the bottom of the pot, simply turn down the temperature. If you notice any lumps in the sauce, use a fork to break them up.
If the teriyaki sauce is still too thin, bring it to a boil. This will help to thicken it further.
If you find that your sauce is lacking flavour, add soy sauce instead of water.
If the teriyaki sauce is sticking to the bottom of the pot or vigorously boiling, turn down the heat.
This will help you to be able to taste all the flavours in the sauce and will give you an accurate idea of the consistency of the sauce at a cooler temperature. If the sauce is already at your desired consistency, remove it from the heat.
If your sauce has sugar or gelatin in, it will keep thickening while it cools.
The flavours will weaken slightly as you add water to the sauce.
