About 10 years ago, my grandmother shared some of her starter with me and I've been using that starter and her recipe ever since.  She told me it was sourdough, but the more I look into it, the more I realize that it isn't sourdough at all! 

I keep this starter in the refrigerator and feed it every 3-10 days.  It's liquid.  It smells more sweet than sour.  I feed it sugar, water and potato flakes, let it sit out for 12 hours then back to the refrigerator for at least 3 days before baking with it again.  To make bread, I take out 1 cup of liquid and add it to my flour mixture.  It takes 8-12 hours for the dough to rise, punch it down & form into loaves then it has to rise 8-12 more hours before baking.  The bread is soft, airy and a little sweet, not sour.  It's a wonderful bread, and I have been selling it, but I'm not sure that I should be calling it sourdough.

I haven't seen this type of starter anywhere in all my research. Can anyone give it a name?