In a medium saucepan, pour the 4 cups of almond milk. Heat it over medium heat until it’s warm but not boiling—about 180°F (82°C). Keep stirring gently to avoid scorching the milk.
While the almond milk is warming, whisk together the 2 tablespoons of arrowroot starch and 1/2 teaspoon of agar-agar in a small bowl. Once the almond milk is warm, gradually whisk this mixture into the saucepan. Continue to stir until it thickens slightly, about 5 minutes.
Remove the saucepan from heat and let the mixture cool to around 110°F (43°C). Once cooled, open the vegan probiotic capsule and sprinkle the contents into the mixture. Stir well to ensure even distribution.
Add the 2 teaspoons of pure maple syrup or organic honey to the mixture. Stir until fully dissolved, adjusting sweetness as desired.
Pour the mixture into clean glass jars or containers. Cover them loosely with a lid or cheesecloth to allow airflow. Place your jars in a warm spot in your kitchen where they can sit undisturbed for 12-24 hours. The longer they sit, the tangier your Almond Milk Yogurt will become.
After fermentation, give your yogurt a good stir. If you like it thicker, you can strain it through cheesecloth. Place the yogurt in the refrigerator to chill for at least 4 hours before enjoying.