Innovative snack makers are searching for versatile systems to create products that capture the imagination of consumers.

“They may want to have a quick changeover from a circle-shaped product to a heart or star or even in the shape of the state of Texas,” said Andres Lopez, business development director, Handtmann Inc. “Having that visual uniqueness of your cookies or your products catches customers’ eyes and provides a better position in the market.”

To boost production on high-volume snack lines, Handtmann uses a multilane extruder that relies on a flow divider controlled by a servo motor that volumetrically pushes products out of every lane

Lopez said the process can gently handle delicate inclusions and avoid breakage and bleeding that can affect the quality and visual appeal of cookies, snacks and baked goods.

Nico Roesler, North American snack equipment sales manager, Reading Bakery Systems (RBS), pointed out that snack producers rely on various fillings, such as alternative nut butters, to differentiate their new products from standard peanut butter-filled pretzel nuggets.

Others may combine peanut butter with jelly fillings or savory fillings with sweet, spicy or globally inspired seasonings.

“As snack makers look to capitalize on this trend, they need flexible equipment that can make both standard extruded products like pretzel minis, but also more complex co-extruded products like filled products,” he said. “The RBS low-pressure extruder can make all these types of extruded snacks on one piece of equipment with minimal changeover.”

Co-extrusion often comes with a toolkit of dies, cutters, nozzles and more to make products of various shapes and textures.

Matteo Pasquali, applications manager, soft dough and cookies, GEA Bakery, said a die can be used to produce filled snacks by simultaneously extruding an outer shell and an inner filling, then using a rotary cutter to create an encrusted biscuit or a guillotine to portion out fruit or jam bars.

“The process works by forcing a mixture of ingredients through a specially designed die, using pressure to shape the product and achieve the desired texture,” he said. “This method can enhance the nutritional value, shelf life and portability of bakery items, making them more appealing to modern consumers seeking quick and easy meal solutions.”

Rafael Alvarenga, area sales manager, Wenger Manufacturing, explained how the co-extrusion process can also combine two or more sets of extruded product streams into one singular final product.

“A special die design is needed that allows the injection of sweet or savory fillers directly into the main product stream as it comes out of the die plate,” he said. “Nozzles must be set to inject the paste materials in a precise, consistent manner. Knowledge of individual ingredient characteristics and how they will behave when combined, such as with fat migration, is a key factor for success.”

One key consideration in this process involves the ratio of dough to filling.

“If the dough jacket or wall is too thin, the filling is destined to burst out of the pocket and create a mess in the baking process,” Roesler said. “If the dough jacket is too thick, the final product quality suffers because there isn’t enough filling in each bite. A solid rule of thumb is to target an outer nozzle twice the size of the inner one. If you’re using a 4-mm diameter filling nozzle, you’d want a dough jacket nozzle that’s about 8 mm in diameter.”

Lopez noted that an incorrect ratio of filling to dough also may discolor the final product if the filling migrates out.

He said Handtmann co-extruders have traveling depositing heads that add filling as the system pinch cuts the dough to create a tighter seal.

Meanwhile, Roesler said RBS is innovating the extrusion process using different shapes of stainless-steel nozzles.

“Filled sticks that are much longer than a standard pretzel nugget can be made using much more narrow nozzles,” he said. “Additionally, flat nozzles can be used to create a flatter filled nugget.”

Pasquali pointed out GEA’s custom-designed dies or nozzles can create a wide range of rings, stars, curls or animal shapes for puffed snacks and other products. 

Bühler offers coloration kits for making a kaleidoscope of snacks, said Mike Shaw, sales manager, snacks and cereals, North America, Bühler. Typically, one color is stored in each tank and injected into the die of the extruder. To make a multi-hued product, the system relies on a continuous, programmable timing process. 

“You can run X number of seconds of green, X number of seconds of red, then other different colors in various amounts,” he explained.

Other liquids can be pumped into the extruder in three injection ports per barrel. Shaw noted that processors can also take steam out to make a denser product or add it in to make a softer snack.

Moreover, feeders at any point during the extrusion process can add inclusions and other dry ingredients to modify a product’s mouthfeel.

Advances in software and systems integration controls can also fine-tune the process by adjusting mechanical thermal cooking as well as an extruder’s capacity rates, temperature, screw speed, moisture, pressure and specific mechanical energy.

This article is an excerpt from the March 2025 issue of Baking & Snack. To read the entire feature on Extrusion, click here.