In a medium saucepan, combine apple cider vinegar, granulated sugar, brown sugar, garlic powder, ground ginger, turmeric (if using), salt, and optional crushed red pepper flakes. Place over medium heat and stir until sugars dissolve completely. Bring to a gentle boil for about 5 minutes.

Once boiling, carefully add drained pineapple chunks, stirring to coat them evenly in syrup. Reduce heat to low and simmer for 15-20 minutes, stirring occasionally, until syrup thickens and pineapple becomes glossy and tender.

Remove from heat and let cool slightly. Spoon the mixture into sterilized jars, ensuring even distribution. Cool to room temperature before sealing tightly. For maximum flavor, refrigerate jars for at least 24 hours before serving.