Yogurt works the same as acidic elements in marinades, working to break down the meat’s surface proteins and allowing the marinade to penetrate inside.
Yogurt has the presence of culture (i.e. bacteria) and mild acidity, two unique properties that allow it to tenderize and flavor meat like no other marinade can.
Heavily acidic marinades have the potential to toughen meat instead of tenderize it, which can make it rubbery. Yogurt has a more gentle acidity that will make meat tender.
With a pH range of 4 to 5, yogurt needs time in order to properly break down the collagen proteins. Anywhere from 12 to 24 hours may be necessary to marinate your meat.
Don’t worry about the flavor that plain, tangy yogurt might bring to your meat. Yogurt is really a blank slate that can be flavored with a number of herbs and spices.
Once you cook the meat, the sugars in the yogurt will caramelize and give your meat a subtly sweet flavor and crispy texture, forming a beautiful crust.