Nineteen times out of twenty when I make a salad dressing from olive oil, salt, dill, garlic and apple cider vinegar, blended in a pint measuring cup with an electric powered hand mixer, it comes out a nice, creamy liquid. The twentieth time it turns into something much thicker, a kind of dip that is really delicious. I gather this is called, "emulsification." However, it only happens infrequently by accident, no matter how I vary the amounts of ingredients. Can you tell me hos to make this happen reliably? Thanks!