Homemade sour cream

Yesterday I started my first attempt at making homemade sour cream.  I found many recipes on the internet and decided to use the overnight method.  Use a quart canning jar or something similar and rinse with hot water.  Then add 2 cups of half and half and 3 tablespoons of buttermilk.  Place lid on and shake ingredients together.  Leave out on the counter over night until desired thickness is achieved.   Stir before serving.  Will keep about 3 weeks in refrigerator.  This really tastes like what you buy from the store but less expensive and you can make it the day before you want to use it.  How simple is that!  After tasting this I won't be buying sour cream from the store anymore.