Fill a canning jar to the top with crushed ice
Place 0.1 oz of ginger root, 0.1 oz of lemongrass, and 0.1 oz of mint into a shaker and muddle
Pour in 1 oz of lime juice, 1 oz of agave syrup, and 2 oz of London dry gin
Fill the shaker with ice cubes and shake gently
Pour through a strainer and sieve into the canning jar
Top with ginger beer