How 2-way humidity control works
2-way humidity control works by continually responding and adjusting to the outside temperature and climate by either adding or removing humidity—as needed—to maintain a predetermined level of relative humidity (RH) inside of packages and containers. Maintaining an ideal and constant relative humidity means your product won’t lose or gain any moisture. Instead, it’ll be maintained at its ideal moisture level throughout its intended shelf-life and/or usage-life. Furthermore, it’ll never encounter any moisture fluctuations along the way.

What’s more, the Humidipak is available in virtually any RH level, from 10% to 95% RH, making it useful for a wide variety of applications, including art conservation, fine wood instruments, many food products, pharmaceuticals, fine cigars and tobacco, and many more.

Best of all, Humidipak is very cost effective, maintenance-free and simple to implement into any packaging line or end-user application.

Other products work just 1-way
There are numerous commercial products on the market that only provide 1-way control, meaning they’ll give off moisture or absorb moisture, whether the product or package needs it or not.

Desiccants
Desiccants attempt to dry the air to approach 0% relative humidity whether the packaged product needs to be drier or not.

Silica gel
Although other commercial products, such as silica gel or propylene glycol, attempt to achieve a specific relative humidity at some middle or higher level. These “1-way” products are less effective because they will not both give off or absorb water-vapor as dictated by the environment. Instead, they tend to create fluctuations, by design, within a given range which, in some cases, can be harmful to the products they attempt to protect.

Humidifiers
Humidifiers work only 1-way by driving the inside RH to 100% relative humidity (if no air leaks or uncontrolled loss of headspace were allowed) regardless if the packaged product needs moisture or not.

Accuracy to (+/-) 1% by responding to temperature & climate changes
The Humidipak is different than all other technologies. Any product or material placed into a container with a Humidipak inside will be kept at the desired humidity level, +/- 1%. If the humidity in the chamber falls below the desired level, water-vapor will pass into the chamber to restore the humidity. Also, if the humidity is greater than the desired level, the Humidipak will absorb enough of the excess moisture to restore the desired humidity.

Patent-protected technology
Humidipak’s 2-way humidity control technology has been awarded several broad-based patents, both U.S. and International, in the field of non-electronic control of relative humidity within enclosed containers and packages. The patented technology is referred to as “Humidipak.”

Natural, safe and environmentally friendly
The foundation of the technology is based on a property well known to physical chemists. It combines the formulation of a saturated solution of a soluble substance designed to maintain a specific level of relative humidity. The product consists of a gelled, saturated solution that is filled into a pouch (or other form) with very high water-vapor transmission permeability—but does not allow liquid-water to pass through or leak into the container.

Freedom for packaging engineers when trying to deal with gases
In the past, packing engineers have been forced to sacrifice moisture considerations in favor of managing the gases associated with packaging some products, such as produce. In such cases, the packaging films that were used needed to allow the gases to escape and subsequently, moisture would escape as well. The unfortunate end result is a product that’s well below its ideal water activity and moisture-content.

Moisture-management and oxygen absorber, all-in-one
The Humidipak technology is also available in a combination version combining moisture-management with an oxygen scavenger (all-in-one), or combining it with a mold inhibitor. Both products make it feasible to maintain a higher level of relative humidity while avoiding the increased risk of mold associated with higher humidity levels.

Designed to satisfy any application—and relative humidity level
The technology utilized in the Humidipak principle can be executed in a full range of desired relative humidity levels and package physical shapes. The most common package form is a pouch, similar to a condiment packet found at fast food restaurants. It must be physically shaped to conform to the end application requirements. It must hold the saturated solution within the package without danger of leakage or rupturing under unforeseen conditions. But primarily, the package must allow the water-vapor to freely permeate its walls in either direction. In a humidity environment higher than desired, it must have room for the water-vapor to enter the pouch from its exterior and be condensed into water. Conversely, it must have water vapor available in the headspace to permeate through the package walls to increase the relative humidity if it’s lower than the desired level.

Examples of uses
Many products perform best when the water content, measured as relative humidity, is optimal. Raisins and brown sugar are most succulent at 70 to 75% but molds grow above 75%. Paper properties are measured at 50%. Wood and leather should be kept between 35 and 60%; string instruments are best when kept at about 50%. Static electricity develops below 20% thus powdered materials should be between 35 to 60%. Oxidative rancidity is inhibited above 30%, so baked goods, spices, herbs and pharmaceuticals have an optimal humidity for stability. Premium tobacco is best at 70%. Fresh produce is typically best above 80 to 85% RH.

Getting Started
Humidipak products are cost effective and it’s super easy to get started. When we embark on a new application of this technology, a number of factors are considered which either we (or the customer) must generate. See our Getting Started section for more details.

First, what are the product requirements? What relative humidity is optimal to preserve the product being protected? Knowing this, we can determine which formulation can be used.

The physical volume of the unit being protected, its moisture content, its tolerance to moisture gain or loss, the outer package of the product being protected, the area of the country the product will be exposed to and the shelf life desired all must be taken into account when developing the total control system.

When we have identified these data points, our staff is then in a position to develop a product that can potentially solve some very significant and long-term relative humidity problems that have been obstacles for years.