Pour the cooked rice into a large bowl. You’ll need a container made of materials that will not react with the vinegar. Glass or enameled earthenware work well. Do not use iron or plastic.

Using a potato masker or the back of a fork, mash the rice for five minutes, so that it has formed a paste.

Pour the malt vinegar over the rice.

Affix cheesecloth to the top of the bowl with a rubber band or tie. This will allow your vinegar to breathe while keeping undesirable elements out.

Store the container in a warm, dark place for three days. Inside a kitchen cabinet or pantry is usually fine. Stir once a day.

Strain the liquid through the cheesecloth into a saucepan.

Pour in the sugar and bring to a slow boil.

Once the sugar burns out, boil the vinegar for ten minutes.

Let cool and bottle the vinegar in a well-sealed glass container