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How To Make Soy Yogurt

Soy milk is the best vegan milk for making yogurt. Unlike other vegan milks, soy milk naturally contains both enough protein to curdle upon fermentation with no additional thickeners, and enough fat for a rich and creamy taste. Homemade soy yogurt is a great way to add healthy bacteria to your diet, without shelling out on expensive vegan yogurts with additives and sugars. Furthermore, many store bought yogurts are heat-treated, killing some of the bacteria, and go through long transport and storage chains. With homemade yogurt, you can enjoy freshly fermented yogurt at its full vigor. Although fermenting at home might seem intimidating at first, it’s really very easy!

To make soy yogurt, you only need soy milk, a source of probiotic culture, and a way to keep it in the right temperature range for 8-10 hours.

two jars fruit shake
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There are many species of bacteria that help turn milk into yogurt. Generally speaking, any dairy yogurt culture can be used as a starting point for a vegan yogurt culture. There are are many options for where to first source your probiotic culture: you can add a little commercial yogurt (plant-based or not), homemade yogurt, vegan yogurt starter packet, or the contents of a probiotic capsule. After your first batch, use a little bit of each previous batch of yogurt to inoculate the next: this helps further adapt the culture to your soy milk and improve it over time. By the second or third batch, your yogurt should be turning out good. Feel free to discard the remainder of the early batches if they aren’t to your taste. Your yogurt will only improve with each batch!

We find that adding sugar to boost the culture isn’t necessary, but some people choose to do so.

A device is needed to maintain your inoculated soy milk at the optimal fermentation temperature of 108-112 °F for anywhere from 8-24 hours. Some convenient options are yogurt maker devices. If you have an Instant Pot, the yogurt setting works great. Some people also have successfully used ovens with low enough temperature settings, or a warm water bath in an insulated container. Please follow the manufacturer’s instructions for any device.

Ingredients

  • 4-6 cups homemade soy milk, or 1 batch of soy milk from your SoyaJoy machine
  • Optional sugar or sweetener to taste
  • A probiotic source from the list below
    • 1-2 tbsp plain yogurt (commercial or from a previous batch, vegan or dairy)
    • Yogurt starter culture (use amount as instructed on packaging)
    • The contents of 1 probiotic (not prebiotic) capsule
  • Optional flavorings such as 1 tsp vanilla extract

Equipment

  • Soymilk machine
  • Fine mesh sieve or nut milk bag
  • Containers for yogurt
  • Incubator (specialized yogurt maker, Instant Pot with Yogurt setting, or home-rigged setup)

Instructions

  1. Make a batch of soymilk with your machine and strain the soymilk with your sieve or nut milk bag
  2. If adding sugar or flavorings, mix in well. For beginners, we suggest leaving out any additives the first few times.
  3. Allow the soy milk to cool to 108-112 °F so that it won’t kill your probiotics. If you will use an incubator that applies heat, it’s fine to let the soy milk cool below that temperature since it will be heated later. To quickly cool fresh soy milk, use a cold water bath.
  4. Add your probiotic source and mix thoroughly but gently to avoid the formation of foam.
  5. Pour the soy milk into your clean container/s of choice. Do not put the lids on!
  6. Place the containers into your incubator of choice at 108-112 °F. Let the soy milk culture for 8-24 hours, depending on your preferred level of tartness. For beginners we suggest 12 hours. You can start tasting the yogurt at 6 hours to get an idea of how fast the fermentation is progressing. Longer fermentation will make more sour and thick yogurt.
  7. After the fermentation is complete, remove your yogurt containers, put the lids on, and transfer to a refrigerator (cooling on the counter or in an ice bath first if you’re worried about heating up your fridge too much) and refrigerate overnight to develop the best flavor and texture.
  8. Enjoy your yogurt however you like, plain or with toppings like fresh fruit, preserves, nuts, or granola!
  9. Lastly, make sure to save a few tablespoons of your homemade yogurt as starter (keep refrigerated!) for the next batch. This is the most effective and convenient way to get the best results each time! This technique is called “backslopping” and is what most home fermenters do, as well as people before the days of commercial yogurt factories did.

Troubleshooting

  • It’s important to note that if you are making soy yogurt for the first time, it will take about 2-3 rounds for your culture to fully adapt to the soy milk. Have patience and start with smaller batches! Just 2 cups of soy milk is enough for these initial batches.
  • It is generally very safe and easy to make yogurt at home, but please be safe and discard any batches that smell, look, or taste suspicious.

Want thicker yogurt?

A common complaint is that homemade soy yogurt isn’t thick enough. Like typical dairy yogurt, plain soy yogurt normally has a lightly spoonable but still pourable consistency. Thicker yogurts like Greek yogurt are made by straining regular yogurt. Vegan yogurts can also be strained through a doubled-up cheesecloth to remove more liquid. Here are some other ways you can try to thicken your yogurt:

  • Make sure your yogurt culture is fully developed. That means you have cultured at least 3 sequential batches via backslopping. Depending on your culture source, your third batch may be dramatically thicker than the first.
  • Ferment longer – if you’re doing 8 hours, try 12-16.
  • Using more soybeans in your soy milk! We like to use 1 cup (US Customary) of soybeans (measured dry) in the SoyaJoy machine.
  • Check the temperature of your incubator with a thermometer. A malfunctioning incubator machine or insufficiently insulating home-made setup may not be maintaining that crucial 108-112 °F temperature.
  • Try adding thicker ingredients such as coconut cream or cashew cream to your soy milk.
  • Use agar-agar to set your yogurt to a thicker texture. This vegan ingredient is derived from seaweed and is used to add a firm, jelly-like texture to foods. Look up “soy yogurt agar-agar recipe” to find instructions online.