Making iron gall ink from oak galls

Back in May, I was taking a walk around the neighborhood when I came across an oak tree with dozens of galls hanging from the stem. At first I thought these were seed pods and didn't even recognize the tree as an oak, but PlantNet (and later Seek) informed me it was a valley oak. At this point I realized the pulpy brown masses hanging from the stems were oak galls, and I had the idea to make my own iron gall ink like people did in centuries past.