Place the coconut and 2 cups of hot water in a blender and let it sit for 30 minutes to rehydrate the coconut. Then add 2 cups of cold water and blend for 2 minutes. You may want to hold the lid of the blender with a kitchen towel to prevent spills. Let the mixture cool until you can handle touching the liquid for the next step.
Place the nut bag or cheesecloth over a large mixing bowl or pitcher. Pour the coconut milk into the nut bag or cheesecloth. Gather up the edges and squeeze out as much liquid as you can. Add the guar gum and Prebio Plus to the coconut milk, and blend with an immersion blender or place in the blender for about 20 seconds, or until the texture is uniform and resembles heavy cream. (We do this to dissolve the powder, and for even distribution of the naturally-occurring coconut oil.)
Let it cool to 110°F. Stir in the Yogurt Plus Starter. Mix well for even distribution. Do not blend.
Place in jars, or jar, and ferment at 104-110°F for 9-12 hours. A longer fermentation will produce a tarter-tasting yogurt. If you choose the lower temperature, it should be fermented at the longer time.
When the fermentation is complete, place the yogurt (with the lid) in the fridge for at least 6 hours to cool and set. If you like a less lumpy yogurt, you can use a whisk and stir until more uniform in texture.
This will keep in the fridge for up to 4 weeks. Separation is normal with coconut milk so just stir it back together before consuming it if you'd like.