Elderberry Cordial Recipe

I remember my grandmother making this every autumn. I found elderberry bushes growing wild on abandoned train tracks in Illinois when I lived there, and when I spotted them from the car on a trip through the Spanish countryside, I returned with buckets from my sister-in-law to pick the berries and strip them and stuff in Ziplock bags awaiting my return to Madrid, ignoring the stained fingers. I shared with my husband's family at Christmas to their amazement as they didn't know what this fruit was.