my air fryer is burning food on top but it's still raw underneath, even when i shake the basket.

Diagnosis

The Instant Pot Vortex Mini 4-in-1 uses a high-density heating coil located directly above the basket, paired with a high-velocity convection fan. When food burns on top while remaining raw underneath, it indicates a failure in "thermal convection," where the heat is radiating downward in a concentrated beam rather than circulating in a vortex. This is typically caused by a buildup of carbonized grease and food debris on the heating element's protective shroud or the fan blades themselves. When grease splatters onto the heating element, it creates "hot spots" where the carbonized residue retains heat longer than the surrounding metal, intensifying the infrared radiation hitting the top of your food. Simultaneously, if the fan blades are coated in a layer of oil, they lose their aerodynamic efficiency, reducing the cubic feet per minute (CFM) of air being pushed. This means the hot air never reaches the bottom of the basket, leaving your food undercooked while the top is scorched. You can confirm this by running the unit for two minutes and feeling the exhaust vent; if the air feels lukewarm despite the unit being on "High," the airflow is restricted.

How to Fix It

To restore proper heat distribution, you must perform a deep clean of the upper heating assembly and ensure an unobstructed airflow path.

1. Unplug the unit and let it cool completely for at least 30 minutes to avoid burns from the heating element.
2. Remove the air fryer basket entirely. Use a flashlight to inspect the ceiling of the cooking chamber. Look for black, crusty patches of burnt oil on the heating coil or the metal mesh guard.
3. Using a soft-bristled nylon brush or a toothbrush dipped in a mixture of warm water and mild dish soap, gently scrub the metal shroud and the area around the fan intake. Do not use steel wool, as this can damage the protective coating of the element.
4. Use a can of compressed air to blow out the fan vents located at the top and the exhaust vents on the rear of the chassis. This removes dust bunnies and grease clumps that hinder the motor's ability to push air downward.
5. Wipe the interior walls of the chamber with a damp microfiber cloth to remove any residue that could cause smoke or uneven heating.
6. Dry the unit completely with a paper towel before plugging it back in.
7. Test the unit by placing a piece of parchment paper (cut to fit with holes for airflow) at the bottom of the basket to see if the air is circulating effectively.

If That Didn't Work

• Adjust Your Loading Density: If you are filling the basket more than halfway, you are creating a "heat shield" effect. The Vortex Mini has a smaller footprint than full-sized models; overfilling blocks the air from reaching the bottom layer. Reduce your portion size by 30% and test again.
• Modify Your Temperature Strategy: If the top is burning, drop the temperature by 25°F (e.g., from 400°F to 375°F) and increase the cooking time by 3-5 minutes. This allows the heat to penetrate the center of the food without incinerating the exterior.
• Check Basket Seating: Ensure the basket is clicking fully into place. If the basket is slightly skewed, it can create an air pocket that prevents the convection current from cycling back up through the bottom of the tray.
• Preheat the Unit: Run the air fryer empty at 400°F for 3 minutes before adding food. This ensures the fan and element are at peak operating temperature, which helps the air move more aggressively from the moment the food is inserted.

Heads Up

• Avoid using heavy oils or aerosol sprays directly on the basket; these create the carbon buildup on the heating element that causes this specific problem. Use a brush to apply a thin layer of oil to the food instead.
• Never use aluminum foil to cover the bottom of the basket, as this completely blocks the airflow and will cause the motor to overheat or the food to remain raw.
• Clean the exterior rear vents monthly with a vacuum cleaner to prevent the unit from overheating and triggering a thermal shutdown.
• Always shake the basket every 5 minutes for frozen foods to manually redistribute the heat since the Mini model has a more concentrated heat zone than larger air fryers.