Pour the milk in a saucepan and set it on medium heat on the stovetop to boil. Stir it with a spoon a few times so that a film doesn't form on top. When the milk starts boiling, take it off the heat and stir it a few times again to bring down the temperature. While the milk is boiling, line a colander with a cheesecloth that covers it completely and place the colander over a deep bowl. This contraption will be used in the third step.
After a minute or two of stirring the milk, add the vinegar and water solution bit by bit, stirring all the time. The milk will gradually curdle and you will be able to see the solids separating from the liquid. Immediately drain the contents of the saucepan into a cheesecloth lined colander you prepared earlier. It is the solids or cheese (chena) that you want. You can discard the liquid collected in the bowl.
Hold the colander under a stream of cold water and let the liquid drain through. Washing the chena in this way gets rid of the smell of vinegar and prevents the chena from hardening.
Switch off the tap and gather up the sides of the cheesecloth into a ball. With your other hand, press on the outside of this ball to squeeze out all the excess liquid, as much as you reasonably can.
Turn the chena on to a wide platter or board and add the cornflour and white flour to it. Start rubbing it in a to-and-fro motion with the palms of your hand. The chena will come together into a soft dough in a few minutes.Break off small, coin-sized portions of the chena and shape into round balls. Cover the balls with a damp cloth.
Now make the sugar syrup. Put the sugar and 5-6 cups of water to boil in a large saucepan. Let it come to a boil, and as soon as it does, drop the chena balls in the boiling liquid immediately. Cover with a tight fitting lid without any delay and let the balls cook undisturbed on high heat for 10 minutes. After 10 minutes, remove the lid and let them cook for a further 5 minutes. Turn off the heat. The balls will shrink a little but not too much. When cool, transfer the balls along with syrup to a dish and refrigerate. Serve cold after 4-5 hours.