Guide to Using Desiccant Bags Effectively

Guide to Using Desiccant Bags Effectively
Published On:June 10, 2020 Revised On:August 13, 2023

Moisture can cause damage to products, materials, and environments. From electronics to food, moisture can lead to deterioration, mould growth, and other problems. Desiccant bags offer a proactive defence mechanism, intercepting moisture before it can inflict damage. In this article, we will share more on using desiccant bags effectively to combat moisture-related challenges and ensure the protection of items.

Understanding Desiccant Bags

Desiccant bags are compact, often sachet-like packages filled with moisture-absorbing materials. These materials, known as desiccants, can attract and retain moisture from the surrounding atmosphere, reducing humidity levels in enclosed spaces.

The moisture-absorbing agents can maintain low humidity levels in enclosed spaces. They work on the adsorption principle, where moisture is attracted and retained on the surface of the desiccant material. Desiccants possess a high surface area and a strong affinity for water molecules. When placed in an environment with excess moisture, such as a damp storage area or packaging, desiccant bags initiate a chemical and physical attraction with the water vapour.

As moisture-laden air comes into contact with the desiccant material, water molecules adhere to the surface through weak intermolecular forces, such as hydrogen bonding. This binding process effectively removes water from the air, reducing the humidity level within the enclosed space. As the desiccant material becomes saturated with moisture, its capacity diminishes, necessitating replacement or regeneration.

The Different Types of Bags

Desiccant bags come in various formulations, each tailored to specific moisture control requirements and applications. Common desiccants include silica gel, clay, and molecular sieves.

Silica Gel Bags

Silica gel, one of the most well-known and widely used desiccants, is characterized by its amorphous, porous structure. Available in granular or bead forms, silica gel packets possess a high affinity for moisture, making them ideal for various applications. They are versatile, cost-effective, and non-toxic, making them suitable for scenarios where moisture absorption is the primary concern. Silica gel desiccant bags are commonly found in packaging, electronics, leather goods, and pharmaceuticals.

Activated Clay Bags

Clay desiccants, composed of natural montmorillonite clay, exhibit moisture-absorbing properties due to their expansive lattice structure. These bags are well-suited for applications requiring moderate humidity control. Their ability to absorb moisture while releasing heat during the process makes them particularly useful in preventing condensation within the packaging. Clay desiccant bags find their place in textiles, shoes, and food products, where maintaining an optimal moisture balance is essential.

Molecular Sieve Bags

Molecular sieve desiccants are zeolite-based materials with microporous structures that selectively adsorb specific molecules, including water. This property makes them highly effective in precision moisture control applications. Molecular sieve bags are prized for maintaining extremely low humidity levels. They can be used in electronics manufacturing, laboratory equipment, and high-tech industries where slight moisture variations can profoundly affect performance and shelf life.

Best Practices for Using Desiccant Bags

While desiccant bags are effective moisture-controlling agents, their optimal performance relies on careful preparation, strategic placement, and mindful implementation. In this section, we explore the best practices of desiccant bags to safeguard items from the damaging effects of excess humidity.

Prepare the Packaging

Before introducing desiccant bags into the space, ensure the environment is conducive to their effectiveness. Remove any existing moisture sources and debris from the area. Clean surfaces and allow them to dry thoroughly before placing desiccant bags. Address any leaks or sources of water ingress that might undermine the desiccant’s efforts. Ensuring a moisture-tight environment enhances the efficiency of the desiccant packs.

The quantity and type of desiccants required will depend on the volume of the sealed container. The packaging material used is also a factor in deciding the type of desiccants that will be most effective. Apart from choosing these considerations, the most critical component is the quantity of moisture that requires absorption and the rate of the absorption process in the packaging.

Overall storage and shipping conditions impact the product’s results and humidity and temperature requirements. Generally, the type of desiccant can significantly impact its absorption rate capacity and cost. Activated clay has a lower absorption, offering 28% by weight absorption capacity. On the other hand, silica gel is a moderate desiccant with a medium absorption capacity by weight at 38%. Molecular sieves are active desiccants offering the highest absorption rate capacity by weight at 20%.

Having Proper Placement

Desiccants are most effective in sealed moisture barrier bags or rigid, sealed containers. A controlled environment is essential for the optimal absorption of trapped water vapours inside the packaging. If a large amount of new moisture from the outer environment starts getting inside the container or packaging, desiccants as moisture control products will not ensure the best results.

Position desiccant bags in corners, crevices, and other areas prone to moisture accumulation. These spots are often where condensation and humidity are most problematic. When storing items in containers, bags, or boxes, place desiccant bags alongside or within the items. This ensures that the surrounding air remains dry. Distribute desiccant bags evenly for larger spaces to prevent moisture accumulation in specific areas. Ensure that desiccants are accessible and can interact with the surrounding air.

Regular Inspection and Replacement

Regularly inspect desiccant bags for signs of saturation. Indicating desiccants change colour as they absorb moisture, providing a visual cue that replacement is needed. Establish a schedule for replacing or regenerating desiccant bags, especially in high-humidity environments.

This prevents the bags from becoming overwhelmed and losing their effectiveness. For storage or shipping items, replace desiccant bags at specified intervals to ensure consistent moisture control. There are several methods to monitor humidity:

  • Humidity Data Loggers: These devices measure relative humidity and provide real-time data. Place them near the desiccant bags to gauge their impact.
  • Weight Inspection: Regularly assess the physical condition of the desiccant bags. It would be time for a replacement if they are heavier than the original weight. The weight requirement would depend on the absorption rate capacity of the selected moisture absorber.
  • Humidity Indicators:  Use a humidity indicator card with desiccants for humidity control. The humidity indicator card placed inside the packaging helps the user to monitor the humidity levels. Once there is a colour change, it is an indication to replace the desiccant.
  • Indicating Silica Gel: Interpreting the colour change depends on the specific desiccant and its manufacturer’s guidelines. Typically, a blue or orange indicating desiccant will turn pink when saturated, while an orange indicating desiccant might shift to green or colourless.


Desiccant bags can help against moisture-related problems. By understanding their principles, proper usage, and strategic placement, preserve the quality of products. At Stream Peak, we manufacture an extensive selection of desiccant bags with ISO 9001 and ISO 14001 certifications.

Our commitment to quality is reflected in the daily tests and checks conducted within our QA laboratory. Our desiccants are tailored to the safety requirements of food and pharmaceutical products. For more information, feel free to get in touch with our packaging engineers for an appointment. Customization is also available upon request, and purchase is also available from our online store.