Basically, you pick a bunch of oak leaves Rinse them Boil some water depending on the batch size Put oak leaves in a mesh bag then add to water AKA, make Oak Leaf Tea Add a little bit of ginger plus any other spices you'd like, then add the honey and yeast (after the must has cooled)
Yes, the later in the season they have less sugar and more tannins Just watch out if you get them very late, like right before they change color, as the excessive tannins will make it syrupy and will trap CO2 bubbles It can lead to exploding bottles or foaming when uncorked