Rinse the blackcurrants and pick out any stems. Nothing kills joy like a surprising twig in your jelly.

In a heavy-bottomed pot, combine berries, water (if using), and lemon juice. Bring to a simmer, mashing occasionally to release their juice.

Simmer 10–15 minutes until the mixture looks saucy and smells pleasantly tart.

If you’re chasing a firmer set, stir in pectin now and bring to a boil for 1–2 minutes. Otherwise, skip it and keep things silky.

Push the mixture through a fine sieve or cheesecloth to remove seeds. Yes, time for a quick patience test; the prize is silky jelly.

Return the strained juice to the pot. Add sugar and a pinch of salt. Cook on medium heat, stirring constantly until the sugar dissolves and the mixture thickens to a nappe (that’s culinary talk for coat-the-back-of-a-spoon).

Do the wrinkle test on a chilled plate: a drop should wrinkle slightly. If not, cook a bit longer. If you overdo it, you’ll have jelly that’s more jam than jelly—not ideal, but edible.

Pour hot jelly into sterilized jars, seal, and let cool. Store in the fridge for up to a month or process for longer shelf life if you’re feeling fancy.