If you’re using fresh elderberries, start by harvesting them from their stems. The berries grow in clusters, so you’ll need to pull the small berries off the larger stem clusters. Freezing the berries first makes this process much easier and cleaner, as it allows you to strip the berries off without mashing them. If you're using dried elderberries, you can skip this step, as they don't need to be stripped.

After you’ve removed the berries from their stems, place them in a bowl of water and rinse gently to remove any dirt or debris. If you notice any leaves or small twigs, remove these as they can contribute a bitter taste to the juice. Make sure to only use the berries, as the stems and seeds are not suitable for consumption.

Add the prepared elderberries to a medium-sized saucepan. If you’re using fresh elderberries, add 2 cups of water to the pot. If you’re using dried elderberries, add 3-4 cups of water. Bring the mixture to a boil, then reduce the heat and simmer for about 10 minutes for fresh elderberries, or 20 minutes for dried elderberries. During this time, the berries will break down and release their juice, turning the water a deep purple color.

Once the berries have softened and the liquid has taken on a rich color, use a spatula or spoon to press the berries against the side of the pot to help release any remaining juice. After pressing, let the mixture simmer for an additional 5 minutes to ensure that all of the juice has been extracted.

Remove the pot from the heat and let the berry mixture cool slightly. Then, strain it through a fine mesh strainer or cheesecloth placed over a bowl or large measuring cup. Use the back of a spoon or spatula to press the remaining pulp, extracting as much juice as possible. Be sure to discard the leftover pulp and seeds, as they aren’t suitable for consumption.