Subbing ice for water:

You can totally sub in ice or snow if that's all you can find! Simply transfer to a large pot and heat over low-heat. Continue cooking until the mixture appears completely liquid. A toothpick inserted in the center should come out wet.

To make frozen water (ice):

Pour water into "ice cube trays" (available from most big box stores.) Be careful not to overfill the trays, the vegan water will expand slightly as it freezes. Place it as level as possible and freeze for 3-4 hours (shorter or longer depending on the quality of your freezer.) Avoid checking the progress too often or it will take longer. Be patient! The cubes should be solid all the way through, you should not be able to insert a toothpick (if you can, put trays back in freezer and wait for another 2-3 hours.) Store in the freezer. The frozen water will re-liquefy if not kept in the freezer. If this happens, pop the trays back in the freezer for another 1-4 hours, or until water appears solid again. This shouldn't affect the quality of the recipe. Will last indefinitely in frozen state but the flavour can deteriorate after a couple of months.