Before I try it, has anyone had any success doing the cold start method using Ultra Filtered like Fairlife in the Instant Pot? I’ve done this successfully hundreds of times with store bought yogurt as a starter (stoneyfield) , just not sure about these starters working the same way.
Good question asked at the right time - before starting 
Answer: Do not do that because:
The bacteria in the starter hibernate and in order to work the conditions must be right.
They need to be added to boiled in advance milk which is cooled down to lukewarm.
The milk also needs to be whole dairy milk preferably the cheapest milk with no preservatives and additives. The ultra-filtered and other ‘‘ultra’’ mediums suggest a high level of processing and this is never good when start making yogurt from scratch.
Recultivation when using ready yoghurt is a different process in which already activated cultures are used.
Please check our youtube channel and fermentation stages to see and understand what is going to happen during the fermentation Fermentation
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