Using the back of a chef's knife, lightly \"crack\" the allspice, peppercorns, cloves, and cardamom pods. In a small skillet over medium heat, toast the cracked spices and cinnamon sticks until very fragrant, about 1 minute. In a medium saucepan, bring the water up to a boil. Add the toasted spices to the pot along with the rooibos tea and ginger. Lower the heat and let the tea simmer for 18-20 minutes. Remove the rooibos masala chai from the heat and run it through a fine strainer into a bowl. At this point, stir in the vanilla, sea salt, and maple syrup. Let the masala rooibos chai concentrate cool completely before storing in a sealed jar in the fridge for up to a week. To make a latte: combine 8oz of the masala rooibos chai concentrate with the plant-based milk and heat using your preferred method–stovetop or microwave.