Wash berries; remove green caps. Place about half of the berries in a large kettle. Use a slotted spoon or potato masher to crush berries; add the remaining berries and crush again. Add the water. Heat to boiling; reduce heat. Cook, uncovered, over low heat for 5 minutes, stirring occasionally.
Line a strainer or colander with a double layer of 100-percent-cotton cheesecloth; set over a large bowl. Pour berry mixture into strainer. Press to drain all juice. Discard strawberry mixture. Measure 6 cups of the juice.
In a 3- or 4-quart saucepan or kettle heat the juice to a rolling boil; stir in the sugar. Continue boiling about 30 minutes or until mixture is slightly thickened, stirring occasionally to prevent sticking.
Pour syrup into four hot, sterilized half-pint jars, leaving a 1/4-inch headspace. Wipe jar rims; adjust lids. Process filled jars in a boiling-water canner for 5 minutes (start timing when water returns to boil). Remove jars from canner; cool on wire racks.