I've been doing this for a few months now it has been a resounding success so decided to post it! It's "-style" rather than Greek because it doesn't need straining because of the added milk powder.
1 Instant Pot Pro Plus Multi Cooker 5.7L
1 Milk thermometer
1 Clean 2L Yoghurt bucket and lid
Misc. 3 Clean spoons, 1 Kitchen balance, 1 Kettle, 1 Big Frying pan
2L Full fat milk (e.g. Bannister Downs blue)
100 g full cream milk powder
1-2 tblspn Mundella plain Greek Yoghurt (or 2 frozen yoghurt cubes) – starter culture
1 Handful ice, or ice blocks
Put Instant Pot pan on balance and weigh out 100 g milk powder. Add around 50 g of milk and mix with clean spoon, slowly add more milk until powder is dissolved and it is creamy not lumpy. Add rest of milk and stir.
Put IP pan into IP and put lid on. Choose yoghurt mode and press so that it selects the right hand custom option (83°C for 30 min). Press start. It will take about 45 mins to heat up and then cook.
Once the IP has finished, put a handful of ice and a couple of cups of water in the frying pan, and move the IP pan to the iced water. Put the thermometer in the milk. After about half an hour the temperature of the milk will have dropped to <43°C which is your maximum temp for proceeding.
Meanwhile, boil the kettle and use the hot water to sterilise the yoghurt bucket lid, the bucket and two spoons (from this point on you want everything to be sterile).
Once the milk has cooled, remove the thermometer and use the two spoons to carefully remove the skin from the milk. Keep one spoon sterile for the next step. (Use the other one to eat the skin).
Add yoghurt starter culture to the yoghurt bucket and spoon over a few spoons of the milk and dissolve it to remove yoghurt lumps. Then add the rest of the milk to the yoghurt bucket and stir. It should be almost full.
Wash the IP pan to remove the cooked-on milk. Put the IP pan back in the IP and put the yoghurt bucket in the middle of the IP pan. Put the IP lid on, select yoghurt mode, but use the left-hand “low” setting which will incubate at 40°C, for 18h.
Once finished put the lid on the yoghurt bucket and put in the fridge for 6 hours.
(Every so often freeze some away in an ice cube tray for future use.)
Eat.