*Dressing or dip? Buttermilk will produce a consistency typical of a traditional ranch dressing. Greek yogurt will yield a thicker, dip-like consistency. In either case, I prefer whole or 2% buttermilk or yogurt.
No buttermilk? Sour milk will work. To make a quarter cup of sour milk, add ¾ teaspoon white vinegar or lemon to a liquid measure and then add whole or 2% milk to the ¼ cup line. Let sit for 5 to 10 minutes and then use the amount needed. A few more options: You may also thin Greek yogurt with milk if that’s what you have but prefer a dressing versus dip consistency. Sour cream is yet another alternative to Greek yogurt.
** When possible, I love a combination of herbs and think dill and chives provide the most classic ranch flavor. In a pinch, use 1 teaspoon mix of the dried counterparts.