How to dry herbs in Industrial Microwave Oven

Drying herbs in an industrial continuous microwave oven offers an efficient and scalable method for high-volume herb drying. Continuous microwave ovens are designed for continuous processing, where materials are continuously fed through the system for consistent and even drying. This method is faster than traditional methods and helps retain the herb’s flavor, aroma, and nutritional content.

Here’s a step-by-step guide on how to dry herbs in an industrial continuous microwave oven:

1. Preparation of Herbs

• Harvesting: Select fresh, healthy herbs that are free from pests and contaminants.

• Cleaning: Gently wash the herbs to remove dirt or chemicals. After washing, pat them dry or let them air dry to remove excess moisture before placing them in the microwave oven.

• Sorting: Remove any damaged or wilted parts and trim the stems if necessary. You want uniform pieces to ensure even drying.

2. Set Up the Continuous Microwave Oven

• Low Temperature Drying: Industrial microwave ovens can dry herbs at a very low temperature ,such as 50 degree, but can achieve a good drying result & sterilization function to kill bacteria & insect eggs. Meanwhile, low temperature can preserve the herbs’ quality.

• Power and Frequency: Industrial continuous microwave ovens use microwave energy to heat and evaporate moisture. Set the      microwave’s power (typically between 30% to 50%) to ensure that the herbs do not get overheated. The frequency of microwave energy typically ranges from 915 MHz to 2.45 GHz, depending on the machine.

3. Feeding the Herbs

• Feeding Mechanism: Use the continuous feeding system  to evenly distribute the herbs onto the conveyor or tray inside the      microwave tunnel. Herbs should be spread evenly in a single layer to ensure even exposure to microwaves. 

  Based on different herbs, choose different feeding system, such as big leave choose conveyor, granule type can choose vibration input. 

  
  

• Conveyor Speed: Adjust the conveyor belt speed      according to the moisture content of the herbs. A typical drying process      may take between 5 to 30 minutes, depending on the type of herb,      moisture content, and microwave settings. Faster speeds can be used for      herbs with lower moisture content, while slower speeds might be needed for      more moisture-laden herbs.

4. Drying Process

• Continuous      Exposure: As the herbs move through the      microwave oven, they are continuously exposed to microwave energy, which rapidly      evaporates the moisture. The microwave energy penetrates the material,      causing the water molecules to vibrate and release heat, which accelerates      the drying process.

• Monitoring: During the drying process, the herbs need to be monitored to      ensure they don’t get overheated or dried unevenly. Depending on the      system, you may be able to monitor moisture content in real-time using      sensors or feedback from the system.

• Humidity      Control: Maintain low humidity in the oven to      allow the moisture to escape. Some systems may have humidity control or      venting systems that remove the evaporated moisture from the chamber.      Ensure the humidity does not exceed the capacity of the system, as this could      lead to incomplete drying.

  
  

5. Finishing and Cooling

• Post-Drying      Cooling: After the herbs discharging from the      continuous microwave oven, they will still contain some residual heat.      Allow the herbs to cool in a dry, well-ventilated area before packaging.

• Test      for Doneness: The herbs should feel dry,      brittle, and crisp. When the herbs break or crumble easily between your      fingers, they are fully dried.

• Drying      Time: The total drying time can vary, but      typical drying for herbs in a continuous microwave oven will take 5 to      30 minutes, depending on the herb type and initial moisture content.

6. Storage

• Packaging: Once cooled, store the dried herbs in airtight containers      such as glass jars, vacuum-sealed bags, or Mylar bags with desiccants to      prevent reabsorption of moisture.

• Storage      Location: Keep the containers in a cool, dark,      and dry place to preserve the herbs’ potency, color, and aroma.

7. Additional Considerations

• Herb      Type Variations: Different herbs have different moisture contents and drying times. Delicate herbs like mint and      basil may dry faster than thicker herbs like rosemary or thyme. You may need to adjust conveyor speeds and microwave settings depending on the      herb type.

• Batch      Size: The continuous nature of the system allows for large-scale drying, but we also can supply batch microwave      dryer for the small scale herbs with turntable.

  
  

• System      Calibration: Regularly calibrate the system      for optimal performance. Ensure that the microwave power, temperature, and      conveyor speed are all correctly set to avoid over-drying or uneven      results.

8. Troubleshooting

• Uneven      Drying: If you notice uneven drying, check      that the herbs are evenly distributed on the conveyor and ensure that      airflow and humidity control systems are functioning properly.

• Overheating: If the herbs appear burnt or too dry, lower the power or      speed up the conveyor. Always dry in smaller increments and check the      herbs regularly.

• Moisture      Retention: If the herbs still feel moist after      drying, adjust the power and conveyor speed or ensure proper airflow and      humidity control to finish the process.

By using a continuous microwave oven, you can efficiently dry large volumes of herbs, preserving their quality, flavor, and nutrients.

For specific herbs, welcome to contact Gspring Machinery for professional technology design to choose a suitable microwave oven for your herbs.