Ginger Beer Concentrate

INGREDIENTS

• 1 1/4 pounds fresh ginger, roughly peeled
• 2 cups filtered water, divided
• 1 cup freshly squeezed lime juice (from 4 to 5 limes), plus more as garnish
• 1 1/4 to 1 1/2 cups of agave nectar, honey or pure cane sugar (to taste, see note)
• club soda