Select the Yogurt setting on the Instant Pot and place three widemouthed pint jars or one 7-cup Pyrex storage container in the pot.
Pour the Ripple® milk into a medium saucepan. Heat over medium-low heat, whisking occasionally, until the temperature reaches 110-115ºF. Immediately remove from heat.
Whisk in the container of Silk yogurt until it is thoroughly blended into the Ripple milk.
Remove the widemouthed jars or Pyrex from the Instant Pot, and ladle the mixture into them. Cover with Saran Wrap and lower into the Instant Pot.
Reset the program on the Instant Pot, reselect the Yogurt program, and set it for 8 hours for mild yogurt, or 12 hours for tangier yogurt.
When the cooking program ends, transfer the cultured yogurt to the refrigerator to chill. Let chill at least 8 hours before serving.