I make yogurt from Straus Family creamery organic milk (SF Bay Area), and I strain out some of the whey to make it thicker - like Greek-style yogurt. I use the whey instead of water to make sourdough bread (I understand it aids in rising as well as nutrition). My question is, how long does whey last in the refrigerator? How do we know when its too old to use?
All thoughts, scientific or not, are welcome.