Start by peeling and chopping the fresh pineapple into bite-sized chunks, ensuring you have about four cups. Next, slice the jalapeños lengthwise, removing the seeds and membranes if you prefer a milder kick. Gather all your ingredients.

In a medium-sized saucepan, combine one cup of apple cider vinegar, four cups of sugar, one tablespoon of grated fresh ginger, and the juice of one lemon. Heat the mixture over medium heat, stirring frequently until the sugar dissolves and the syrup begins to simmer.

Once the syrup is ready, reduce the heat to low and carefully add the chopped pineapple and sliced jalapeños. Continue to cook the mixture, stirring occasionally, until the pineapple becomes tender and the liquid thickens into a syrupy consistency, about 20-30 minutes.

Carefully pour the hot mixture into sterilized jars, leaving about a half-inch headspace. Wipe the jar rims before sealing with sterilized lids, and allow to cool at room temperature for 12-24 hours.