In a large pan over medium high heat, stir the water and 6 cups extra fine sugar until the sugar is dissolved. Add food coloring, if desired, then bring to a full boil while stirring frequently. Turn off the heat and ladle ½ cup of the syrup into a large coffee mug. Set aside and let it cool. Leave the rest of the syrup in the pan, removed from the heat, and allow to cool covered with plastic wrap overnight.

Meanwhile, spread the ¼ cup granulated sugar onto a small plate. Dip one edge of each skewer into the cooled ½ cup reserved syrup, then roll the dipped side of the skewer in the granulated sugar. Place on a baking sheet lined with plastic wrap. Repeat for all skewers and add more sugar as needed. Allow the dipped skewers to dry also overnight.

The next day, stick the un-dipped side of the skewers into a foam block, about 1-inch spaced from each other. Place upside down into the pan with the sugar syrup so that the sugar-coated edges are now dipped into the syrup. Be careful to not place any sticks too close to the bottom or edge of the pan. Allow to rest for 7 days for the crystals to form and grow. Do not move the pan.

On the 7th day, remove the skewers from the pan. You may need to gently wiggle the sticks to release them from the partially hardened syrup. Some skewers might not turn out as well as others, especially if they were too close to each other or too close to the bottom or edge of the pan.

Transfer to wax paper, plastic wrap or parchment paper to dry for one day. (Turn them every few hours so each side can completely dry.) Wrap the dried rock candy in plastic wrap. Use the leftover syrup to make another batch! (Just repeat the process above starting with dipping and rolling the skewers in the syrup then sugar.)