Orange juice concentrate is often frozen and later made into orange juice by adding water to the mixture. The juice must have the water removed to become a concentrate. The procedure for removing the water is a simple one, though time consuming.
Pour the orange juice into a plastic, thin-necked jug. Allow extra room for the juice to expand. Place the jug in the freezer and allow it to freeze completely. The amount of time it takes to freeze will vary depending on the amount of juice.
Remove the jug and put it upside down over the wide-necked container. Allow the juice to melt and drip into the second container. The water crystals melt slower than the juice, so the initial drips are concentrated orange juice.
Discard the plain ice when the drops are no longer orange. This is not a necessary part of the juice.
Repeating the freeze-and-drip process twice will result in a fine concentrate with minimal water content. Freeze and store the concentrate when it is finished until ready to use.
Allow the ice to melt naturally. Adding heat will result in ice melting faster and more water in the end result.