Adding more ginger flavour

I have just brewed 8L of ginger beer with 1.5 cups of grated ginger. Avb should come out at around 7.5%. I tested the gravity a couple of days ago and it still has a few points to go (using ec1118).

When I tasted it it was nice, had a good amount of ginger burn feeling in the mouth but it didn’t have the ginger flavour to match. Can I add more ginger before bottling? Use ginger powder or just more pure ginger?