In a pot, combine the raspberries, water, sugar, and lemon juice. Stir and bring to a boil. To prevent it from burning, let it simmer for about 5 minutes while stirring often.

For ten minutes, turn the heat down to low and let the mixture boil and bubble. Further thickening will occur as it cools.

Serve warm or let cool and keep in the refrigerator for up to 5 days in a sterilized container (or freeze for up to 2 months).