Allen's Homemade Yogurt

I got a new Instant pot this spring.  When we lived in Prague I bought one on Amazon UK and had it shipped to us.  We used it all the time, and managed to bring it with us when we moved to Croatia.  The bus driver for our ride from Prague to Vienna didn't want to load it (pressure cookers have been used as bombs, we heard).  Then he wanted to charge us about 20 Euros.  I was willing, but only had Czech Koron.  He used his phone to do a converter, and told us 20 Koron, which is about 1 dollar.  His coworker started to disagree, but I turned over the 20 K as fast as I could, smiling and thanking them.  Phew.  Finally when we moved to Ireland I had to leave it behind.  It was way too heavy and bulky, and we were already stressed trying to get our bikes to Dublin.  That's another whole story.

So today I am braving homemade yogurt.  Allen makes it all the time in Scotland, and did when they lived in London, too.  I asked him for his directions, and this is what he told me:

Put half a gallon of milk in the Instant Pot, and push the Yogurt button, then Start.  It will heat to boiling.  Stir occasionally so it doesn't stick to the bottom.  Once it beeps, cool, stirring frequently.  Allen puts his bowl in a sink of cold water to speed it up.  Use a candy thermometer to see when it gets to 115 d or lower.  Add 1/2 - 1 cup yogurt with active culture.  The more yogurt you use, the faster it will be done.  Whisk it to break up and dissolve the yogurt.  Sieve to remove chunks and give the pot a quick clean.  Put yogurt either into glass jars or back in the inner pot.  Click Yogurt button so it ferments (might have to click twice on some models).  Adjust to normal 8 hour program.  Remove after 6 hours for creamy, non-sour yogurt, or 8-11 hours for more sour yogurt, and store in airtight containers or glass jars or Tupperware that seals.  Add 2-3 tsp sugar if desired.