Maybe try drying your fresh ginger for a week before use the dryer it gets the more heat you get from your ginger root. This trick turned my brew into a really nice spicy ginger hit! Maybe even too spicy, now I do half dried old fresh ginger root with half fresh plump ones. Hope this helps for your ginger bite!
My ginger beer gets hotter if I strain the ginger mixture multiple times. So after straining after a simmer of 30 minutes, move the strained ginger mixture into a pan add hot water and boil (5 min). Do this several times (5 times) until strained water runs clearer. It doesn't take more time if you have to top up a 23L drum with hot water.