Prepare the Cucumbers: Wash the cucumbers thoroughly. Cut off the ends and slice them into spears or chips, depending on your preference.

Prepare the Brine: In a medium saucepan, combine the vinegar, water, salt, and sugar. Bring to a boil over medium-high heat, stirring occasionally until the salt and sugar have dissolved.

Flavor the Pickles: Once the brine is boiling and the salt and sugar are dissolved, remove the pan from the heat. Add the garlic, mustard seeds, dill seeds, black peppercorns, and red pepper flakes (if using). Stir to combine.

Pack the Jars: Place the cucumber slices into clean glass jars. If using fresh dill, add a sprig or two to each jar. Pack the cucumbers tightly but without smashing them.

Pour the Brine: Pour the hot brine over the cucumbers, ensuring that they are fully submerged. If needed, you can press the cucumbers down with a clean utensil or use a lid to help keep them submerged.

Cool and Refrigerate: Let the jars cool to room temperature, then seal with lids and refrigerate. Allow the pickles to sit in the fridge for at least 24 hours before eating for the best flavor, though they will continue to develop their taste over time.

Enjoy: Homemade Claussen pickles can be eaten after 24 hours but are best enjoyed after 2-3 days. They’ll keep in the fridge for up to 2 weeks.