April 1, 2015
by Charlotte Atchley
While mixing batters and doughs may seem similar — both aim to combine ingredients into a homogenous mixture — batters have some distinct characteristics that change the priorities bakers pursue in the mixing bowl. For one thing, the development of gluten isn’t important when it comes to batters. Finished products that start as batters aren’t relying on gluten for their structure; therefore, the main purpose in mixing a bread dough — the development of gluten — doesn’t apply. However, bakers who make batter-based products want one thing, consistent finished product quality, and that starts with consistent batter, whether coming from a batch or continuous system.
“It’s extremely important having a consistent batter,” said Kevin Wilkinson, North American sales, Tonelli Group, Parma, Italy. “If you have different specific gravities from batch to batch, you’re going to have different air bubbles and different size cakes. They won’t rise the same.”
While gluten development may not be a concern in batter mixing, even incorporation of ingredients, batter aeration and specific gravity consistency are all critical elements that bakers must control in the mixer to ensure that the batter coming out of the mixer is the same throughout production.
“The more uniform the batter, the more consistent it will be in the baking process,” said Denny Vincent, president, Advanced Food Systems, Columbus, OH. “Your dry ingredients in any batter or dough are only effective once you get them hydrated. If you don’t hydrate flour and sugar, they’re not going to do anything but sit there. The better you can hydrate your ingredients the better quality product you’re going to get in the baking process.”
Getting those dry and wet ingredients together is all about using the proper mixing tools and controlling variables such as temperature and aeration to get the proper specific gravity and the most consistent finished product possible.
Batters may not have to contend with gluten development, but the proper incorporation of ingredients and aeration of the batter is vital to ensuring the finished product remains steady throughout production. “A batter mixer isn’t trying to develop gluten; you just want to get your ingredients incorporated thoroughly with no lumps,” said Terry Bartsch, vice-president of sales, Shaffer Manufacturing, a Baking Bundy Solution, Urbana, OH.
As the demand for consistency has increased, mixers have improved to meet that challenge. “The accuracy of planetary mixers has increased a great deal, and accuracy is an indispensable quality when mixing many ingredients,” said Claire Auffrédou, marketing manager, VMI, Montaigu, France.
To make its mixers more accurate, VMI has optimized all the parameters of its planetary mixer: the speed of the planet gear, the ratio between the speed of the planet gear and the whip, the diameter of the whip and the center distance. “The optimal adjustment of these parameters helps obtain a better overrun,” Ms. Affrédou explained. “Industrial users can, therefore, control their production.”
Having the right mixing tools for the ingredients can also tailor the process to exactly the end-products’ needs.
The scraper, present on most batter mixers, throws ingredients that may have stuck to the side of the mixing bowl back into the fray to be fully incorporated. This ensures that no dry ingredients get left behind in the bowl once the batter is finished. While most scrapers descend into the bowl along the side with the beaters, the scraper in a mixer by Sancassiano, represented in the US by Allied Bakery Equipment, Santa Fe Springs, CA, is attached to the bottom of one of the mixing tools. This prevents the scraper from bending as it descends into stiffer ingredients such as butter or cream cheese.
With a double planetary mixer, bakers get three mixing tools: two beaters, which can be customized to the batter being mixed, and a bowl scraper. Instead of one mixing tool agitating ingredients against the side of the bowl [as is the case in a single planetary mixer], the two beaters mix the batter within each other. “It’s very efficient at getting the incorporation of ingredients to be homogenous quickly and uniformly,” said Damian Morabito, president, Topos Mondial, Pottstown, PA. The mixing tools can be changed out to suit whatever action the baker needs: aeration, beating egg whites or shearing cream cheese, etc.
With inverters controlling Sancassiano’s mixing tools, the speed of the tools isn’t tied to the speed of the scraper, and the baker can control these variables independently. Also, some of the tools have inclined, directional cross-bars. “If the batter beaters rotate one direction, it pushes ingredients up, and if they rotate the other way, it pushes ingredients down,” said Stephen Bloom, vice-president, Allied Bakery Equipment. “By alternating the directions, you really incorporate the ingredients and inclusions.”
The center-driven impeller on Breddo Likwifier’s mixers ensures complete ingredient hydration by pulling all the ingredients through the center of the blender. This prevents dry spots in the batter. “The impeller pulls the batter down through the center, and we have scrapers on the side,” explained Bill Wade, equipment director, Breddo Likwifier Division, Corbion Ingredients, Kansas City, MO. “It ensures a total blend in the tank.” Not only does this create better hydration with fewer lumps, but it also amounts to a much faster mix time.
The rotor/stator mixing arrangement creates shear by pulling the ingredients between the two. That close tolerance incorporates the ingredients together. On Shaffer’s mixer, the rotor is also inclined. This pushes the ingredients side-to-side, not just back and forth, making for more thorough mixing.
The twin screw continuous batter mixer from Reading Bakery Systems, Robesonia, PA, implements a cutting and mixing action to bring together high moisture or high fat content products such as batters and icings that require that high energy mixing. This action with the continuous nature of the mixing creates an efficient as well as consistent mixing process.
Airing it out
While incorporating flour, fat, sugar and eggs into a homogenous mixture is an important function of a batter mixer, air is one of the core ingredients that also gets mixed in. The aeration of batter creates and maintains the specific gravity, which determines such critical characteristics as tenderness, grain, texture and volume of the finished product. Exerting control over aeration exerts control over consistency.
With a closed, sealed mixing bowl, bakers can use pressure to achieve better control over their batters’ specific gravities, according to Mr. Wilkinson. “The bowl is pressurized while mixing,” he said. “This helps create a lower specific gravity by injecting air into the batter for creating light specific gravity products such as whipped creams and batters.”
Without the pressurization, bakers can still reach their desired specific gravity, just with a longer mixing time. The longer the batter mixes, the more air is being added to the batter. Pressurizing the bowl eliminates this need, Mr. Wilkinson noted, as it forces the necessary air into the batter.
Consistency in product quality is all about the baker exerting as much control as possible over the variables that can affect the quality: temperature, time, speed. By controlling the variables, bakers can ensure the quality of the product remains consistent throughout production. “Baking has been an art for a long time,” Mr. Vincent said. “People want to put their own twist on it, but when they do that, a variation pops up. Management would rather have a consistent product across all three shifts.” Computer-controlled systems eliminate the reliance on “the artist” while not only ensuring dependable product quality but also improving it. When it comes to batters, it’s all about maintaining the proper specific gravity.
“Mixing time, mixing process steps and mixing RPM, all of those things in conjunction with the air pressure — if we control those variables, bakers will get consistent specific gravity,” Mr. Wilkinson said.
This kind of control can be found in computer controls. These systems track the mixing process and all of the variables that go into it, providing operators with plenty of data. Batter mixing can be a complicated process with a lengthy list of steps that can be programmed into a computer-controlled system.
“You’re able to build intricate recipes from the panel screen,” Mr. Morabito explained. “In some cake baking, there’s sometimes seven or eight steps before the final batter. With a recipe-driven menu, you can set those steps up and select the mix speeds and times you want for each.”
Once all these steps are programmed into the computer as a recipe, they can happen with the push of a button, and the computer executes the recipe the same way every single time. The time and speed at which the mixer runs is all automatically controlled, preventing any variation due to the operator. The computer can prompt an operator to add ingredients manually, or that process can be automated as well.
With the elimination of human error, the only variable left is the ingredients — their temperature, quality and scaling — and some of that can also be controlled by automation. Zeppelin Systems USA, for instance, controls the temperature of the ingredients coming into its shear stream slurry mixer.
Control is exerted to ensure that the targeted specific gravity and mixing consistency is maintained from batch to batch or throughout production. “The accuracy of specific gravity is what they want to achieve,” said Bob Peck, vice-president of engineering, E.T. Oakes Corp., Hauppauge, NY. “We use mass flow meters to monitor the product flow, and we have mass gas meters to very accurately control the air injection.”
In Tanis Food Tec’s continuous batter mixers, the required amount of air is dosed into the batter by a mass flow controller into a fully closed system. The amount of air is calculated based on the specific weight of the slurry going into the mixer and the target weight the bakers want to achieve when the batter is finished. “With a continuous system, we can control the amount and quality of the air and see air as an ingredient,” said Piet Vader, sales manager, Tanis Food Tec, represented exclusively in the US by Naegele, Inc., Alsip, IL.
Temperature control is also important in batter mixing to maintain the functionality of the ingredients and the consistency of the batter. “We want the batter to be heated in the oven, not in the mixer,” Mr. Vader said. Tanis Food Tec’s rotors and stators are water-jacketed to control the temperature and prevent the batter from heating up. The tanks are also jacketed to cool off if necessary.
On its continuous mixer, E.T. Oakes provides bakers with plenty of data through digital temperature monitors and pressure monitors.
While batter mixing can be a complicated process with plenty of variables, computer-controlled systems help bakers manage their recipes easier with more consistent results. “It can be a very complex mixing process, but it’s easily run once the baker finds a perfect recipe,” Mr. Wilkinson said.
Despite being simplistic on the surface, mixing can be a complicated process to achieve a homogenous batter and proper aeration. To repeat the process and turn out the same finished product requires the proper tools and computer systems for efficient mixing, to eliminate human error and to maintain repeatable results.