Hi! Each full sized Vitamix comes equipped with a 2 or 2.2 peak horsepower motor which moves the blades in your container at a high speed to pulverize the ingredients. On occasion during blending, especially with thicker mixtures, air pockets can form in the container. This gives the illusion that the blades aren’t moving in the pitcher and can affect the blending performance. This is something you can easily resolve by blending on the highest speed & using your tamper to work the ingredients through the blades while your Vitamix is running! With the lid firmly in place, insert the tamper through the lid plug opening and move it around the four corners of the container. As the food travels around the side of the container, the tamper directs it right into the blades. If there is an air pocket around the blade, the tamper will release the air pocket and create a continuous flow of food through the blades. Be sure to also keep in mind that certain ingredients and recipes are thick or sticky in nature, so you may have to tamp for the entire blending time!