Pick the beautyberries when they’re fully ripe — the clusters should be bright and well-formed. Remove leaves, stems and any debris. Rinse the berries in a colander under running water to wash off any dust or insects.

Place the cleaned berries in a large non-reactive pot. Add the 8 cups of water. Bring to a boil, then reduce the heat and simmer for about 20 minutes. During this time, mash the berries lightly with a potato masher so they release their juice and colour. The liquid may look brownish at first — that’s normal. After the simmering, allow the mixture to cool slightly.

Line a sieve or colander with several layers of cheesecloth (or use a jelly bag). Pour the berry-water mixture through the cloth, pressing gently to extract as much juice as possible. Discard the solids (you can compost them). You should aim to get ~3 cups of berry liquid (or whatever your recipe calls for). Some recipes suggest reducing the juice further to concentrate flavour.

Clean the pot and return the measured berry juice to it (e.g., 3 cups). Stir in the fruit pectin until well dissolved. Add the optional butter if you’re using it. Bring the mixture back to a full rolling boil — one that doesn’t stop when stirred.

Immediately after reaching the full rolling boil, add the sugar and the lemon juice all at once. Stir well to dissolve the sugar. Bring it back to a full rolling boil and boil hard for exactly 1 minute (or according to your pectin’s directions). Stir constantly to prevent scorching and scrape the sides.

If foam has formed on the top, skim it off with a spoon (or rely on the butter to minimise it). Meanwhile, have your mason jars sterilised and hot (you can pre-heat them in hot water). Ladle the jelly mixture into the jars, leaving about ¼ inch headspace. Wipe the rim of each jar with a clean damp cloth, put on the lid and screw the band finger-tight.

If you intend to store long-term, process the jars in a boiling water bath canner for the recommended time (often ~10 minutes) depending on altitude. Allow the jars to sit undisturbed at room temperature for 12-24 hours to set. After this, check seals, label, and store. If you prefer to skip canning, you can refrigerate the jars and consume within a few weeks.

After cooling, the jelly will firm up further. Unscrew the lid, taste a bit, and enjoy. Spread it on toast, pair it with cheese, or stir it into yogurt.