Buttermilk - There are options?

I sometimes make recipes what call for buttermilk.  Unlike my parents, I cannot just add pepper and drink any leftovers.  So, when I have a recipe that calls for buttermilk, I have to make lots, make a couple of recipes OR make my own buttermilk.  Not always options that I prefer.  Recently, I found another wonderful option:  Powdered Buttermilk.

It is wonderful - instructions on the container let you make 1/3 cup or 1 cup, so options of measurement are easily calculated.  It is shelf stable until opened, then it needs refrigerated.  This container is good until 2018.  Fabulous.  I was not paid to write this, I just think it is a wonderful option for those of us who do not prefer buttermilk.  Of course, there are those like my niece whose son recently learned how to make butter by shaking cream in a jar.  She will have LOTS of buttermilk (if she lets him make butter as often as he wants to).