This might be frustrating, but there is an incredible way to make yoghurt and sour cream, you just need to source the starter.
I never bothered making yoghurt because we didn’t have a hot water cylinder and I didn’t want to buy a plastic yoghurt maker, so it was hard to keep warm…
Then I discovered Caspian Sea Yoghurt which requires absolutely nothing other than some cold milk and sitting on the bench for 12 -24 hours. Hooray! And its a really good pro-biotic one.
If you use cream instead of milk it turns into sour cream. All these things tend to go round in circles though, unless you can source the cream and milk without plastic, which you might be able to, depending on where you live.
I obtained my starter Ruth from Waybe, but I accidentally killed it, then I got a new one from Trish Allen, who has kept it alive for years between her and a friend (good to have a back up person). Trish does fermenting classes and gives the starter out to attendees. Perhaps google “fermenting workshops nz” or ask at your nearest environment centre for possible opportunities to get hold of the starter.
You can have some of mine if you are coming past and I haven’t killed it again.
One you have the starter, this is how you make it.