5 bowls of water.

1. First add 1 bowl of sweet potato flour and 1 bowl of water to the container and mix evenly.

2. Pour the remaining 4 bowls of water into the pot.

3. Filter the prepared starch water and put it into the pot (you can add appropriate amount of salt to taste), turn on medium-low heat, and stir constantly with a spatula or spatula while cooking.

4. Stir until the starch water slowly thickens and becomes transparent. Pick it up with a spatula and the starch paste will fall down like a waterfall without breaking. Then turn off the heat.

5. Brush oil (anti-stick) on the inner wall of the mold filled with jelly, pour the cooked starch paste into the mold, scrape it flat, and cool it to form a powder base.