Everything You Need to Know About Scent Control
November 06, 2013
Like germs, odors are everywhere. Hormones, chemicals, what we eat and even where we live affect how we smell. Regardless of the source, whitetails and other game animals quickly learn to associate human odors with danger, avoiding hunters like the plague. The trick is to prevent deer and other critters from winding you.
Oh, if only it were that simple! Scientists have found that whitetails can smell human scent farther than bloodhounds and can detect up to six different odors at once. This means the cover scent you applied before going hunting won't necessarily prevent deer from smelling your body odor, the gas you pumped on your way to the stand or the pepperoni pizza you ate for lunch.
To combat whitetails' super-sniffers, the hunting industry has developed a plethora of high-tech, scent-control technologies. Things such as zeolite, engineered polymers, activated carbon and antimicrobial silver aren't science fiction. They are the latest in human scent control, and they've been proven in laboratory tests to prevent or eliminate human odors. But none of these technologies is effective at eliminating 100 percent of odors 100 percent of the time.
So, you should never ignore wind direction when hunting. But when used correctly and in conjunction with a comprehensive scent-elimination regimen, today's scent-control technologies will help you fool a deer's nose and fill your tag. Let's look at today's most popular scent-control technologies, covering where they came from, how they work and how they help conceal a hunter's presence.
Like many other technological innovations, zeolite isn't new but its use in the hunting industry is. Zeolite is a naturally occurring mineral formed when volcanic ash reacts with alkaline groundwater. Its highly porous structure makes it an odor-collecting machine, trapping odors and removing them from the environment.
The first known use of zeolite was by the Romans to filter water flowing through their aqua ducts. In the 1970s, engineers began using it to filter wastewater
ammonia and decontaminate radioactive material. Today, synthetic zeolite has countless applications — everything from cleaning up pollution spills to filtering swimming pools. What makes it so valuable is that it can be chemically engineered to trap molecules of varying sizes.
"We developed synthetic zeolite that targets human odor molecules of different sizes," said Mark Estrada, director of hunt and fish products for Under Armour. "We then infused silver antimicrobials into the zeolite molecules to destroy bacteria that cause human odors."
The synthetic zeolite Under Armour uses only adsorbs human odors. It won't trap odors from gasoline, cigarette smoke, deer urine or any other smells associated with hunters.
Notice I didn't say zeolite absorbs odors. In absorption, something penetrates the molecules of an absorbent and changes its chemical structure. In contrast, adsorption occurs when odors adhere to the surface of an adsorbent.
Under Armour claims its Scent Control hunting apparel lasts 10 times longer than carbon-based technology. This doesn't mean Scent Control is more effective than activated carbon.
"We're not claiming numbers, only that our Scent Control garments will last longer and are able to be regenerated back to nearly 100 percent after 50 washes," Estrada added.
Reactivating apparel with synthetic zeolite is simple: just throw it in the wash. "All the odors are washed out and the clothing's recharged through normal laundering," Under Armour marketing consultant Eddie Stevenson said. "Just use scent-free detergent with no UV brighteners. Drying [in a clothes dryer] isn't necessary."
When it comes to cleaning and filtration, nothing beats activated carbon. Also known as activated charcoal, carbon filtration was used by the Egyptians to clean air and water. Today it is used at industrial cleanup sites, for air filtration in automobiles and is even ingested when someone swallows poison.
The term "activated" means the carbon is processed to have a surface area that is covered with tiny pores that chemically adsorb, or trap, odor molecules that contact them. The surface of activated carbon granules is covered with so many microscopic pores that just one gram can have a total surface area of 500 square meters.
In 2012, Scent-Lok introduced Carbon Alloy, a new innovation that combines activated carbon, zeolite and a new, treated carbon to capture different types of human odors. Activated carbon is naturally derived from coconut shells, while treated carbon is created through a proprietary process where carbon particles are modified to enhance adsorption of specific odor molecules.
"Our activated carbon, zeolite and treated carbon are blended together to target specific human odors, like those created bacterially, hormonally and from bad breath," said Scent-Lok President Greg Sesselmann.
For years, Scent-Lok has used Intertek — an international testing firm that specializes in textiles — to test the effectiveness of its carbon-based technology. One test involves administering 3 milliliters of a synthetic human odor to different Carbon Alloy fabrics at zero, one, five, 10 and 20 wash and dry cycles. Results revealed that the company's carbon-based technology captured 96 to 99 percent of concentrated human odor.
To remove unwanted odors and regenerate carbon-based apparel, place it in a clothes dryer on high for 40 minutes. Despite some claims to the contrary, Scent-Lok said independent testing has shown household dryers emit high enough temperatures to regenerate its apparel. You can also get rid of adsorbed odors by placing clothing in an airtight container and filling it with ozone.
Earlier this year, Robinson Outdoor Products completely revamped its popular ScentBlocker line of scent-eliminating clothing with the introduction of Trinity Technology, an engineered polymer resin that traps human odors. The synthetic material, which is bonded to the fabric in ScentBlocker garments, contains macro pores that provide a large surface area for human odor molecules to enter and micro pores to trap them.
"Macro pores are like entrances to a cave," explained Keith Edberg, Robinson's operations manager. "Once the odors pass through the macro pores, they're captured by the micro pores."
Robinson used several independent labs to test Trinity, finding it has the capacity to adsorb human odors 40 percent more than activated carbon and 200 percent more than zeolite. This doesn't necessarily mean Trinity works better in the field — only that it has the capacity to trap more human odor molecules.
"Like all odor-adsorption technologies, our fabric must come into contact with odors for the odors to become trapped," Edberg said. "If you give odor an easy way out, it's going to take it. Don't leave the top of your jacket or your cuffs open. You have to force the odors through the fabric."
Like Carbon Alloy, you can regenerate Trinity apparel by putting it in a dryer on high for 40 minutes. Robinson Outdoors recommends only washing Trinity clothing when soiled, as washing breaks down the fabric more quickly.
Like zeolite, antimicrobial technology isn't new. Ancient Egyptians and Greeks used antimicrobials to treat infection more than 2,000 years ago. An antimicrobial is an agent that kills or inhibits the growth of bacteria. Unlike activated carbon and zeolite, which trap human odors, antimicrobials actually penetrate the cell walls of bacteria and prevent reproduction.
Antimicrobial materials such as silver are applied to fabrics to control human odor. Keep in mind that an antimicrobial destroys bacteria that are the cause of many human odors — it has no effect on odors once they've formed.
"Antimicrobials reduce bacteria next to the skin, thereby reducing the odors that come from the bacteria," Sesselmann said. "Scientists have identified over 350 human odors, and only some have a relationship to bacteria that lives on your body. Antimicrobials have no effect on human odors that come from other sources."
For example, sulphur and sulfide compounds found in breath odors are often caused by medications, diet and one's overall health. Antimicrobials will have no effect on eliminating these odors. It's also important to note that for an antimicrobial to work, it must come into contact with bacteria. It can't "grab" bacteria out of the air or somehow draw microorganisms in.
Today a host of companies use antimicrobials in hunting apparel, scent-eliminating sprays, body washes and laundry detergents. Scent-Lok uses AEGIS; a proprietary antimicrobial developed by a private company. AEGIS permanently bonds to the fabric for the life of the garment, preventing odors from forming. Scent-Lok also adds proprietary enzymes o its Base Slayers, Field Spray, Body and Hair Wash and Carbon Reactivating Detergent.
Similarly, Primos uses a combination of colloidal silver and enzymes in its Control Freak line of odor-control products. Collodial silver consists of silver particles that have been microscopically dispersed in another substance (often a liquid) during the production process.
"The Control Freak alters the molecular structure of certain chemicals responsible for human odors, changing them into something that doesn't smell human," Primos Product Manager Jason Harris said.
Hunter's Specialties also produces a litany of scent-control offerings under its well-known Scent-A-Way line, including field spray, antibacterial soap, shampoo and conditioner, laundry detergent and antiperspirant.
"We use many different methods to attack odors, such as encapsulation, oxidation, neutralization and bioconversion," Hunter's Specialties co-founder David Forbes said. "You can't just use one approach to get rid of variety of odors."
Two years ago, Wildlife Research Center (WRC) released Super Charged Scent Killer Spray, a proprietary blend of antimicrobials and enzymes that target a wide range of human odors. "Our technology latches onto odor molecules and prevents them from developing into a gas," WRC Communications Director Ron Bice said.
Although WRC won't release its study results, the company claims testing done at Rutgers University found its latest product is more than 99 percent effective at stopping replicated human odor.
Tink's uses another antimicrobial, Byotrol, to eliminate hundreds of odors produced by the human body and environment. Developed in 2000 by the British company Byotrol PLC, Byotrol is used worldwide in hospitals and food factories. Byotrol's technology literally tears microbes apart, leaving behind a coating that continues to kill bacteria and odors after drying on fabrics. Numerous tests have found that Byotrol not only outperforms bleach, hydrogen peroxide and alcohol-based sanitizers, but is safe to use on skin and other sensitive surfaces.
"We are the only company that's authorized to use Byotrol in the hunting industry," said Terry Rohm of Tink's. "Testing conducted in several countries has shown it's effective at destroying odors days or even weeks after it's been applied."
None of the companies I spoke with would reveal all the ingredients in their sprays, body washes and shampoos. But each one believes their odor-eliminating products put the kibosh on human odors.
First discovered in 1785, ozone (O3) is a naturally occurring gas found in the Earth's atmosphere. Today it is used to disinfect surgical instruments, destroy bacteria in food factories and remove odors in public restrooms.
Ozone is a highly unstable gas, so it wants to attach to other molecules, including those that comprise human odors. When it does, it alters the chemical composition of human odor molecules, stomping out human scent.
In 2007, Ozonics became the first to manufacture an ozone generator specifically for use while hunting. The company's HR-200 in-the-field ozone generator uses an electric current to change oxygen molecules into ozone and then projects them downwind of your location using a silent fan. The HR-200 is meant to be mounted above the hunter's head on stand or in a ground blind, and because ozone molecules are heavier than air, they filter down through your scent stream as they travel down wind, bonding with your odor molecules and making them undetectable to deer and other game.
Keep in mind that ozone can only alter odor molecules that it comes into contact with. Swirling winds will often blow your scent away from the ozone curtain created by the HR-200, meaning some of your scent can get to deer.
Ozone doesn't destroy all odors — it just changes them in something that doesn't smell human. And ozone has a mild odor itself, most commonly described as something similar to chlorine.
"Our testing has revealed that about 50 percent of all deer won't react to ozone odors at all, while a small percentage will smell something but not recognize it as coming from a human predator," said Dennis Fink, Ozonics co-owner.
Although Ozonics holds a patent on in-the-field ozone use, many other companies produce portable ozone generators designed to stomp out stench on hunting clothing and equipment. For the ozone to remove odors on clothing, boots and hunting equipment, it must be administered in a small, confined, airtight space. Unfold and periodically readjust hunting apparel throughout the decontamination process to ensure ozone comes into contact with all fabric surfaces. And wear rubber gloves whenever handling disinfected clothing to prevent odor transfer from your hands onto disinfected clothing.