Been doing this for quite a while now bros. First batch splits, second batch is better and 3rd batch and there on is awesome. I run 41.1C for 36hrs in a souvide I have sitting in my pantry. I make 6L at a time and start my next 6L with a 1/4 cup of yoghurt in each new container from my last fresh, uncontaminated container (havent opened it, used a sponn in it etc.). I use boiling water from the kettle to sterilise, nothing fancy for me and have made dozens of batches.

I usually sweeten it with stevia and add fresh fruit and nuts but YMMV. Eat it every day.

-Buy a half decent, cheap souvide I gotSpoiler!

-Buy some jars with silicon lids like thisSpoiler!I got tall skinny 1L ones as I can fit 6 in my container.

-Buy a bin container with a split lidSpoiler!, cut down to size of containers & souvide so lid sits 1/2"-1" above whatever containers you buy. Drill a hole in the lid for souvide. Basically trying to make a cheap version of thisSpoiler!. You can skip making a cheap container, they arent that expensive but mine cost me under $20 AUS and 15mins of my time.

-Buy UHT full cream milk (I think that's 3.25% in the US) or half and half if you want higher fat (cant use fresh milk). I buy the 1L variety and use 1L containers so it works perfect.

-Buy some inulin powder (I get from bulk supps) and whatever probiotic caps you want ( I use L. reuteri and a few othersSpoiler!). You only need a cap for the first batch and then use left over yoghurt to seed future batches so long as you sterilise each time and use uncontaminated yoghurt to seed.

-Make your own probiotic yogurt that is way cheaper than anything you can buy and 10000% healthier probiotic wise. Inital capital is recouped quickly if you eat yogurt every day like I do and even quicker if you use probiotics which are mostly a waste of money FYI. From what I understand you can try any probiotic caps you want but I have only tried the 3 in the link so far. The L. reuteri comes in caps, dont ge the tabs that you have to crush it's a waste of time and money.