2, take an old soda bottle rinse clean, fill the empty bottle with about 81% of the bottle volume of cooling water.

3. Add sugar and a small amount of your favorite fruit flavor to the bottle.

4. Add sodium bicarbonate (baking soda) at a ratio of 100 to 2, gently stir with chopsticks, and then add citric acid at a ratio of 80 to 2 after the sodium bicarbonate (baking soda) is dissolved, and immediately screw the bottle tightly with the lid.

5. Put the bottle in the refrigerator to cool down and drink.