Bring the 2 ¼ pints of milk to just under boiling point and then pour the milk into a glass bowl (Don’t use metal).
Let the milk cool to about 104°F. Pour the already made yogurt into the milk carefully without disturbing the skin that may have formed on the surface of the milk.
Cover with a cloth, place in a warm location for 8 to 12 hours or overnight.
When the yogurt has thickened after 8-12 hours drain the extra liquid and store in the refrigerator.