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What is Gulp? Olfactory Overload and the Science of Gulp!

Deeply rooted in science, Berkley GULP! attracts fish on a molecular level helping you catch more fish.

Fish possess a powerful sense of smell—one which helps them locate forage and feed. Specialized cells called “chemoreceptors” line a fish’s nostril and are capable of detecting individual scent molecules dispersed in water in the parts per billion range.

Dogs, by comparison, who lean heavily on their sense of smell, have noses 1,000 to 10,000 times more sensitive than humans (depending on the breed of course). However, some fish species possess a sense of smell much better than even their dog counterparts (10,000 to 100,000 times more sensitive).

Decades ago, manufacturers began to recognize a fish’s ability to locate their food via scent. They brewed all sorts of elixirs and potions designed to “attract” fish, but in reality, they attracted and hooked fishermen more effectively than the fish themselves.


Fish attractants have been around for decades. Since the early days, manufacturers have concocted every sort of topical attractant. While these were purportedly based in “science,” most were mixed in bathtubs, trashcans, and kitchen sinks.

In the early 1990s, through the collaborative work of Berkley’s Senior Chemist, John Prochnow, renowned fisheries biologist Dr. Keith Jones, and other researchers, work began in earnest to develop an attractant that was based in science and, most importantly, helped anglers catch more fish.

After thousands of hours of laboratory research and development, and years of field testing, Berkley Gulp! was introduced to the market in 2001 under the name of Power Naturals. The product name was changed to Gulp! in 2002 when the range of bait offerings was greatly expanded. The introduction of Gulp! was a quantum leap forward in scent science, representing a crowning achievement for the Berkley research and development team. Since its introduction, Gulp! has changed the way we fish.


Prior to Gulp! there were soft plastic baits that had “scent and flavor” incorporated into the baits—not just topically. Berkley’s researchers determined, in order to maximize their attractiveness, a complete manufacturing paradigm shift was required.

While in their laboratories, Prochnow and Dr. Jones discovered some very interesting things about how-to manufacture flavored and scented soft baits and how fish reacted positively to them if the perfect combination of flavorings and scents were achieved.

Prochnow and Jones discovered the majority of soft plastic baits are molded from a man-made plastic polymer resin, polyvinyl chloride, or “PVC.” If this material sounds familiar, it’s because PVC is what your house plumbing is made from.

PVC is designed to carry water without leaking, meaning the material is waterproof. As such, when scent is added to PVC-based soft plastics, only the scents/flavorants on the bait’s surface will release and dissipate quickly into the water, while the rest of the scent is trapped inside the bait, unable to escape.

Prochnow and Dr. Jones also discovered the vast majority of competitive fish attractants are oil-based. These oil-based scents simply cannot mix with the water around them (oil and water do not mix). That means the scent is incapable of dissolving in the water and attracting fish. So, while baits with these types of attractants may have an odor to us humans when we open the package, that scent will be nearly undetectable to fish who can only detect scents that are soluble in the water.


As we’ve seen, traditional PVC-based soft plastics are hydrophobic, or water repelling. Water is the transport vehicle for all natural scents. The scent of baitfish, for instance, is distributed via the water that surrounds them. As this signature scent is distributed, gamefish pick up the scent, which leads them to the baitfish. In contrast, when PVC-based soft plastics are submerged in water, their ability to “release” their internal flavorings are greatly inhibited.

In direct contrast, Gulp! baits were designed to take advantage of a natural process called osmosis. Gulp! baits are blended from water-based polymers that are hydrophilic (water-loving). Because of its hydrophilic nature, water permeates throughout Gulp! baits (not unlike water seeping through a paper towel), washing copious amounts of fish attracting scent into the water column. In fact, scientists have calculated that Gulp! scent dispersion creates a field 400-times greater than standard soft plastic baits.


In addition to its rapid scent release, Gulp!’s fish attracting potency is derived from its triple-tiered flavorant system. Since the vast majority of game fish are carnivores, Gulp! uses a complex cocktail of flavorings that appeal to the dietary desires of the fish.

Just as humans often enjoy flavoring their steaks with different spices, Gulp! utilizes a multi-tier proprietary active ingredients that serve essentially as flavor enhancers, elements that add additional attractiveness to the bait.

A third set of very unique flavorants are added to shape-specific baits. So, for example, shrimp baits are enhanced to taste like shrimp, while minnow-shaped baits are flavored to taste like minnows.


Because of its rapid scent release and high attractant potency, Gulp! effectively bridges the gap between natural and artificial baits. Natural baits, such as baitfish, worms, crabs and shrimp have long been appreciated by anglers for their natural appeal. To a degree, this appeal is founded in the biological make-up of predatory fish and how they view their prey.

By survival necessity, predatory fish are physically “tuned” to the sensory stimuli emitted by their common prey. However, natural baits have several distinct disadvantages. Natural baits are plagued by poor durability, muted color when stressed (i.e., fished with), size selection, and rapid spoilage.

Additionally, some natural baits are also only available on a seasonal basis, while others are nearing depletion or are subject to disease. Gulp!, on the other hand, lasts for years in the package, comes in a wide assortment of different fish-catching shapes, sizes, and colors, and is uniformly available throughout the year. Additionally, Gulp! baits demonstrate outstanding durability, greatly outlasting natural baits. And, in many instances, Gulp! has been shown to out fish natural baits when fished head-to-head.

Given its broader selection of bait shapes, Gulp! is much better suited for active cast-and-retrieve presentations, offering presentation styles in many situations where natural baits cannot be practically used.

The introduction of Gulp! changed forever the way we fish. Gulp! baits provide fishermen with the first real alternative to natural baits. Gulp! baits offer powerful scent attracting components which ultimately allow fishermen to catch more fish. Berkley Gulp!—we’ve done the science, you catch the fish.

Explore Berkley Gulp! for Saltwater

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