Place your cheese vat of milk in a Mad Millie incubator. Fill the space between the cheese vat and incubator wall with water which is the same temperature, or on cooler days, slightly warmer than the milk in the cheese vat. Every hour, check the temperature of the water. Add more warm water if necessary during the day to maintain the temperature. This will provide you with an insulating blanket to keep the milk at the desired temperature. Instead of using an incubator you can also keep your container of milk in a hot water cupboard or warm place in the house.
In order to sweeten your yoghurt, you can add sugar to your milk whilst heating. Or as an alternative, you can add jam to your completed yoghurt to create a sweetened fruit style yoghurt.
Ultra heat treated milk denatures more proteins than normal milk, which results in a better consistency.