Add water to kudzu powder and dissolve well.When using potato starch, dissolve it in1 tablespoon of water in advance and add it at the very end to thickenit.
Transfer to a pan, add apple cider vinegar,sugar, and salted koji, and heat on medium low heat until thickened.
When it becomes thick and the liquidbecomes transparent, add pepper as you like.
It's done. The amount can be used up at one time, butif you find it, put it in a clean bottle and store it in the refrigerator.