The day before brewing, smash up the juniper berries and soak them in a liter of water until the next day, then remove them.
Dough in the malt with 10 liters of water to result in a mash at 50 °C. Keep that temperature for 30 minutes, then add another 10 liters of hot water to result in a mash temperature of 68 °C. If that’s too much effort, just add 10 liters of water of at least 50 °C, then heat up to that temperature.
Then do a Vorlauf until the wort is clear, and lauter. Sparge with hot water. Boil for 90 minutes. At the end of the boil, add the juniper berry infusion, and chill the wort to about 20 °C. Add chopped up ginger to the wort, and pitch an ale yeast.
Depending on your brew kit’s efficiency, the resulting beer should come out with about 13.5 °P, 80 IBU and 5.5 % ABV. The bitterness is obviously crazy high, but with some aging, it should subside and smooth out.
https://dafteejit.com/2016/02/mannheimer-braunbier/