Calculating Desiccant Amounts for Moisture Control

Calculating Desiccant Amounts for Moisture Control
Published On:June 3, 2020 Revised On:December 13, 2023

Moisture, often invisible, can undermine the integrity and quality of numerous materials and products, from electronics and artefacts to food items and industrial components. Corrosion eats away metals, mould proliferates on surfaces, and delicate materials are degraded.

Fortunately, desiccants offer a solution by absorbing excess moisture and maintaining optimal humidity levels. However, the effectiveness of desiccants hinges on one crucial factor: using the right amount. This article will determine how much desiccant to use for different scenarios, ensuring that products remain safeguarded against moisture-related damage.

Understanding Desiccants

Desiccants, often termed moisture-absorbers, are specialized substances that extract moisture from the surrounding environment, effectively lowering humidity levels. Its fundamental purpose is to safeguard against the detrimental effects of excessive moisture. The desiccants act as moisture magnets through adsorption, capturing water vapour molecules and securing them to their surfaces.

Desiccants find widespread application across various contexts, including storage facilities, transport containers, and maintenance centres. Their versatility is evident in their usage, ranging from safeguarding military munitions to thwarting mould growth on footwear.

The moisture absorbers also play a crucial role in preserving artefacts within display cases, shielding delicate items from the damaging effects of high humidity. Furthermore, the absorbers offer vital protection to metallic components, preventing rust formation and the tarnishing of silver.

In environments where consumables are involved, food-grade, non-toxic desiccant packs are used. These packs enhance the shelf life of food items by minimizing moisture-induced spoilage. However, it’s essential to emphasize that desiccants are not meant for direct consumption. Ingesting desiccants can lead to adverse effects such as nausea, vomiting, and headaches.

Factors Influencing the Quantity

The effectiveness of desiccants depends on various factors, and understanding these factors is crucial in determining the appropriate quantity of desiccant required for a particular application. The key factors influencing desiccant quantity are temperature and humidity levels, packaging size and material, and material sensitivity.

  1. Temperature and Humidity Levels: High temperatures and humidity levels increase the potential for moisture to accumulate within a sealed environment. The dew point, the temperature at which air becomes saturated with moisture, plays a significant role in determining when condensation occurs. When the air temperature drops to or below the dew point, moisture condenses on surfaces, potentially leading to damage. The higher the humidity and the larger the temperature fluctuations, the more desiccant is required to maintain dry conditions.
  2. Packaging Size and Material: Larger containers or packaging with greater internal volume require more desiccant to ensure moisture-absorbing capacity throughout the space. Additionally, the material of the packaging can affect the permeability of moisture. For instance, materials like paper or cardboard may allow moisture to penetrate more easily than metal or plastic. Permeable packaging materials may require additional desiccant to counteract the increased moisture infiltration.
  3. Material Sensitivity: Different materials react differently to moisture exposure. Some materials, such as electronics, pharmaceuticals, food products, and certain chemicals, are highly sensitive to moisture and can experience degradation, corrosion, spoilage, or reduced effectiveness if exposed to excess humidity. Desiccants maintain an optimal moisture level and safeguard these materials from damage. The moisture sensitivity level of the protected material often determines the desiccant quantity required.

Calculating Desiccant Quantity

Ensuring the correct amount of desiccant is used is essential for effective moisture control. Several methods and formulas can be employed to calculate the appropriate desiccant quantity based on specific requirements. Here are three common approaches: weight-based calculation, volume-based calculation, and using moisture sorption charts.

While these methods provide a basic framework for calculating desiccant quantity, consulting with desiccant manufacturers, industry guidelines, and experts is recommended to ensure accurate and effective moisture control. Factors such as the type of desiccant, the specific materials being protected, and the anticipated environmental conditions all play a role in determining the ideal desiccant quantity for a given application.

Weight-Based Calculation

This method involves determining the desiccant quantity based on the weight of the packaged goods. The general guideline is to use about 5-10% of the product’s total weight being protected. The exact percentage within this range depends on factors like the moisture sensitivity of the product, expected environmental conditions, and the type of desiccant used.

Formula: Desiccant Quantity (in grams) = Product Weight (in grams) × Desiccant Percentage

For example, if there is a product weighing 1000 grams and a 5% desiccant is desired, the calculation would be: Desiccant Quantity = 1000 grams × 0.05 = 50 grams

Volume-Based Calculation

This approach involves calculating the desiccant quantity based on the packaging volume. This method is particularly useful when dealing with irregularly shaped items or products that take up significant space within the packaging. The desiccant capacity can vary based on the specific desiccant type.

Formula: Desiccant Quantity (in grams) = Container Volume (in cubic centimetres) × Desiccant Capacity (in grams per cubic centimetre)

Moisture Sorption Charts

Moisture sorption charts, also known as adsorption isotherms, represent the relationship between relative humidity and the amount of moisture a desiccant can absorb. These charts are specific to each desiccant type and can help determine the appropriate quantity based on the expected humidity levels.

When using moisture sorption charts: a. Identify the expected humidity level in the packaging environment. b. Locate that humidity level on the chart. c. Read the corresponding desiccant capacity value. d. Calculate the desiccant quantity needed based on the container volume. It’s important to note that the moisture sorption capacity of desiccants can vary with temperature, so it’s advisable to consider temperature conditions when using moisture sorption charts.

Safety Considerations

While desiccants are valuable moisture control packaging solutions, handling them carefully is essential to ensure product effectiveness and personal safety. Desiccants These are not intended for ingestion. If children or pets ingest silica gel or other bulk desiccant materials can pose a choking hazard. Additionally, some desiccants may release dust particles that can be harmful if inhaled.

To ensure safe usage of desiccants, follow these guidelines:

  • Keep Out of Reach: Store desiccant packets and bags in a location that is inaccessible to children and pets.
  • Avoid Ingestion: Desiccants are not meant to be ingested. Ensure that desiccant packets are not accidentally left in packaging that could be mistaken for food.
  • Minimize Inhalation: When handling desiccant materials, avoid creating dust and ensure proper ventilation to prevent inhalation of any particles.
  • Wash Hands: After handling desiccants, wash hands thoroughly to remove any residue from skin.
  • Use Protective Gear: When handling large quantities of desiccants or working in dusty environments, consider using gloves and a dust mask to minimize direct contact and inhalation of particles.
  • Disposal Guidelines: Proper disposal of used desiccants is essential to prevent environmental contamination. Here’s how to dispose of desiccants safely:
  • Non-Toxic and Food-Grade Options: When choosing desiccants, consider opting for non-toxic and food-grade options, especially if the application involves products that may come into contact with food, pharmaceuticals, or sensitive materials. Food-grade desiccants are designed to be safe for direct contact with consumable goods and are generally non-hazardous.


Understanding the principles of desiccant usage and the factors influencing their effectiveness can maintain the quality and shelf life of materials and products vulnerable to moisture-related damage. By deploying appropriate quantities of desiccants and adhering to safety guidelines, mitigate the detrimental effects of excess moisture, ensuring the preservation of products across a broad spectrum of applications.

At Stream Peak, our desiccants undergo rigorous daily testing in our QA laboratory, ensuring their effectiveness and reliability. As manufacturers of desiccant bags that adhere to ISO 9001 and 14001 standards, we take pride in delivering products that meet the highest industry benchmarks.

For moisture control packaging solutions, our team of packaging engineers can provide the optimal desiccant quantity required for specific needs, ensuring that products remain safeguarded against the damaging effects of excess moisture. Feel free to get in touch with us to schedule a no-obligation appointment.