Add the vinegar, water, sugar, sea salt and garlic to a saucepan and bring to a simmer over medium-low flame. Cook for a few minutes until it starts to thicken. (If doing the ginger version then add it here as well )
In a small bowl whisk together the tapioca flour + 2 tbsp of water until smooth then add it to the simmering sauce making sure to stir frequently.
Simmer the sauce another minute or so until thickened to your liking. The sauce will continue to thicken as it cools down so keep that in mind as well. Use a little splash of water to loosen it up a bit if needed.
Allow to cool off completely before storing in tight lid jars in the refrigerator.