When you remove gluten, you add challenges.
Gluten-free products currently are the fastest-growing category of non-traditional baked goods. The global market for gluten-free goods reached $6.2 billion in 2018, a 65 percent increase over 2012, and is expected to grow an additional 7 percent a year through 2025, according to Markets and Markets. They’re popular even though the condition they’re designed for, celiac disease, affects only about 1 percent of the U.S. population. Many consumers who don’t have celiac disease swear by a gluten-free diet, saying it simply makes them feel better.
As gluten-free products increase in popularity, automating their production becomes attractive, or even required. But it’s a particularly challenging kind of scale-up.
“Most of the folks that are coming to us have been doing it by hand, but they’re trying to automate, and that’s the big hurdle for them,” says John Giacoio, vice president of sales for Rheon USA. “Countless people I’ve talked to say the equipment that’s out there for regular bread production does not lend itself to gluten-free formulations.”
That’s because taking gluten out of dough alters its characteristics in ways that often require fundamental changes to processing.
Giacoio recalls the first generation of these products. “It was hard to even call it a dough. Some of them are like batter. And when we run it on our traditional bread equipment or our sheeting lines, it’s a mess. It just cannot be done on that.”
Gary Seiffer, sales specialist for EnSight Solutions, recalls what happened when the demand for gluten-free products began ramping up, about 19 years ago. “I remember panic setting in, because this stuff was not like any kind of dough we’d worked with,” Seiffer says. “There was just no structure – it was more like pancake batter.”
Running into problems
Gluten is protein that elasticizes dough, providing structure and enabling it to trap the carbon dioxide generated by yeast. (This is why many gluten-free formulations don’t use yeast.) Eliminating it often leaves dough that is runnier than conventional bread dough.
The simplest way of dealing with dough that’s more like batter is to treat it like batter, with equipment designed for free-flowing product, like piston fillers. Some early gluten-free formulations were literally dropped or scooped into loaf pans, like so much cake batter. That’s still being done in some cases, says Ken Hagedorn, vice president of sales for Naegele Inc.
“Instead of using your normal bread equipment, which would be a dough-sheeting line or a dough-ball system, they would have to use a depositor, like you would use to put filling down, because that’s the only thing that’s going to handle liquid,” Hagedorn says.
But runny dough often yields a less desirable product, because it can’t rise. This isn’t so much a problem with dense sweet goods like brownies, which don’t use yeast in the first place, and which have other formulation options for thickening the batter. But it’s a big liability with bread.
Sweet goods “usually can get around the issues because they can put more egg in it, they can put more sugar in it,” Hagedorn says. “But you can’t do that with bread dough.” More fundamentally, with no yeast, the dough in the earliest gluten-free products had no way to spontaneously aerate. This yielded a dry, crumbly and generally unappealing product.
Sophisticated gluten-free formulations have ways of getting around that problem. Starches and gums like xanthan give the dough a structure more like conventional bread dough. In some cases, this allows yeast to be used; other formulations use artificial leavening agents.
However, altering the formulation that way still requires adjustments in processing, Seiffer says. “Now they’ve got enough gums and starches in this dough that they’re able to mold a loaf, but you don’t have to sheet it and curl it,” he says. “You just have to mold it almost like freehand molding, but you’re doing it in a machine.”
One of the challenges is that when gluten-free dough is thickened with additives like starches and gums, it becomes sticky. Some bakers dust sticky dough with flour, but that’s problematic with gluten-free formulations. Normal flour can’t be used, and gluten-free flour is too expensive, since flour used for dusting can’t be reclaimed. An alternative is to coat product-handling and baking surfaces with starch or oil, but that also adds to the cost, makes a mess and can interfere with the product’s flavor.
Another way to deal with sticky dough is to lower, whenever possible, the temperature of the equipment surfaces it contacts. This is especially useful with products like flatbreads and pizza crusts, where half or more of the surface is in constant contact with processing equipment.
Most pizza manufacturers heat the surfaces of their crust presses, but some processors of gluten-free pizza don’t, Hagedorn says. “That’s actually been a trend, where people are taking their pizza presses and running them really cold.” The disadvantage is that they don’t get the benefit of a hot press, which gelatinizes and seals the crust’s surface, keeping the sauce and other ingredients from soaking in.
Dealing with sticky, thinner, less elastic gluten-free dough sometimes calls for more than simple tweaks in equipment. What’s often needed is a fundamental change in how the dough is handled – sometimes with equipment that normally isn’t used in baking at all. That’s why Rheon developed the concept of using extruders to process gluten-free dough.
Rheon’s Cornucopia KN Series coextruders are ordinarily used for enrobed or encrusted products ranging from caramels to calzones. Because they can handle super-sticky substances, they’re also suitable for gluten-free products.
“Putting it through the coextruders is what really works for us,” Giacoio says. “We’ve got a lot of bakeries doing that with gluten-free doughs.”
Some bakers are initially put off by the idea of extruding dough, because “extrusion kind of gives you the connotation that it’s going to beat the heck out of it,” Giacoio says. But the advantage of the Rheon extruder is gentle handling. Its ratio of applied pressure to the volume of product emerging from the aperture is less than one-seventh that of conventional extruders, which allows the dough to maintain its integrity, with minimal disruption of particulates.
Another feature is the cutting mechanism, which Rheon calls an “iris.” It uses six pieces of non-stick plastic that come together like a camera lens shutter. The iris was designed to seal fillings into the interior of a product, but it also works well for gluten-free dough. By applying pressure from multiple points, it cuts the dough more evenly and with less stress than a single-action cutter would.
When Rheon’s coextruders handle gluten-free dough, they actually work like single-die extruders, with end users either running dough through both the inner and outer dies, or using just one die and hopper. The dough can come out either in ball shapes or long and thin – as long as the end user wants. This is perfect for products like sausage buns, rolls and baguettes, but it can even be used for bagels.
With gluten-free dough, “you wouldn’t use a traditional bagel former because that’s all belts and it goes down a shaft, and that would just make a mess,” Giacoio says. Instead, with Rheon’s system, the die extrudes two strands of dough, about an inch apart, that are connected at the bottom, dropping them through the iris cutter. Its cutting motion fuses the tops of the strands together (simultaneously forming the bottom of the next bagel), creating a loop of dough. When this loop falls onto the conveyor belt, the pliability of the gluten-free dough makes it assume the round bagel shape.
Baking is another part of processing that requires adjustments for gluten-free dough, especially if chemical leavening additives replace yeast. These aerate the dough through foaming, which reduces or eliminates the proofing step. That has consequences for the next step: baking.
“You don’t have to do the long proof, obviously, because you’re not growing yeast. If anything, you’re going right into the oven,” Seiffer says. “I think from a machine point of view, the oven companies have had to do the most adjustment these days because now you’re baking a little differently.”
Gluten-free dough usually gets baked in ovens that are cooler, at least in the initial zone or stage, than ones for conventional dough. The goal with the latter is to turn its moisture into steam as quickly as possible, to give the crumb (the loaf’s interior) an optimal texture. Gluten-free dough almost always has less moisture, which means it needs less heat.
“When you’re baking with a wheat-based or yeast-based dough, you need to get oven spring, so you need a lot of heat in that first zone to get that dough to go Wow!,” Seiffer says. “But because the chemicals create the cell structure, the oven profile from chamber to chamber is different.” The exact temperature depends on a number of factors like ingredients and loaf size, but in general, the temperature range for gluten-free dough is about 100°F less than for conventional.
Bakers who are starting a new gluten-free product, or automating an existing one for the first time, should thoroughly test any new equipment or concepts before committing to them. Most reputable equipment suppliers will be glad to furnish technical assistance, often within their own testing labs, to scale up a gluten-free formulation.