Control your dough

28-May-2006 - Last updated on 14-Mar-2017 at 17:17 GMT

Related tags Bread Baking

Whether you're handling pastry or bread dough, consistency is the name of the game. Michelle Knott examines how automation can help achieve this

The baking industry is notoriously conservative, but that doesn't stop suppliers from seeking to drive innovation. According to Keith Graham, marketing manager for Baker Perkins, the key is to make sure that the benefits to the products and processes are clear for cautious end users.

"There's a balance to be struck between using automation for the sake of the process and using automation for automation's sake," he says. "We're often fighting conservatism in our customer base. We want to bring them on with technology that they will benefit from, without going too far. If we waited for bakers to demand technology we wouldn't be as far along as we are today."

Baker Perkins has introduced several innovations in its baking machinery over recent months. The latest change at the company has been the name, however. Following the purchase of APV Baker by private investors in April, the Baker Perkins name is making a return to the market for the first time since the 1980s.

The company's most recent technical innovations target the stages between mixing and baking. First, there's the Accurist 2 divider. The divider essentially pushes the dough into a cutting die that divides it into loaf-sized portions, but the Accurist 2 swaps conventional springs and cams for a servo motor that constantly applies the precise amount of pressure required to push each portion of dough into position.

"Bread dough is not a consistent product," explains Graham. "While the dough is waiting to be divided it ferments, which means that the density changes throughout each batch. A well-developed dough does not offer as much resistance. The Accurist 2 senses the pressure and applies just enough."

The more gently the dough is treated, the higher the number of microbubbles retained in the dough structure. But if the divider applies too little pressure, it can't control the weight of each portion properly. The new controls ensure that the pressure of each stroke is optimised individually. "Each stroke of the divider is tailored, so the dough is subjected to the same conditions all the time, regardless of its own condition. The effect of reducing pressure is higher quality bread with a more even crumb and better colour," says Graham.

The company has sold one Accurist 2 in Germany and another in South Africa since the divider was introduced last year.

Next up is the Multitex 4 moulder, which takes dough after the first proving stage. It squeezes the dough through rollers to form a sheet, pressing out oversized bubbles and preparing the dough for coiling, which enables it to fit into tins.

By squeezing the dough through four sets of progressively tighter rollers, rather than three, the Multitex 4 treats the dough more gently at each rolling stage. The resulting loaves are up to 18% softer and the marked improvement in quality has led to rapid acceptance by the industry. Around 30 machines have already been sold around the world.

In March, German company Reimelt announced its radical approach to large-scale dough preparation, which it claims cuts energy consumption by up to 30% and raises dough yield by 2-3%. Although the company says that several features combine to account for the improvements in performance, two aspects of the system's design really stand out.

First, the CodosSystem's modular approach separates mixing and kneading into two distinct stages, which enables the energy applied by the tools in each one to be optimised. The kneading vessel also features a jacket fed with cooling water, which prevents the dough from heating up as it ferments and eliminates the need for more drastic cooling measures, such as the addition of ice or carbon dioxide.

This all adds up to a CodosSystem rated at 3,000kg/h using around 55kW, while conventional dough production uses 80kW. The optimised mixing stage also enables bakers to add more water at the mixing stage without compromising quality, and this leads directly to the improved yield, according to Reimelt.

The second unusual feature is the continuous, automated nature of the system. "When the processes involved in the production of dough are analysed, the result is inevitably the demand for a continuous operating system," explains Hans-Dieter Lehnen, product manager for dough technology. "However, this has not necessarily been achieved due to often inconsistent mixing and kneading requirements. Reimelt's development engineers have cut the Gordian knot by developing two separate units for these two stages of dough production."

The continuous process eliminates any variation between batches, producing a more consistent dough quality and preventing any interruption to downstream processes. "This system avoids variations in quality and scaling weights, which have been inevitable up to now and can result from inconsistent dough ageing with the batch-type system," says Lehnen. Furthermore, because the whole thing is entirely automated, a single operator can monitor a process producing up to 8,000kg/h of dough.

Baking automation

Moving further through the production process, oven manufacturers also have to take care to ensure that they carry the support of their customers with them as they innovate, according to Robert Done, sales manager for Auto-Bake Europe. "There is a trend to greater automation, but suppliers have to be careful they don't scare off the everyday baker. That's why our ovens can be integrated and fully automated or can be used simply as an oven with varying degrees of manual input," he says.

Originally from Australia, Auto-Bake set up its European operation four years ago and will have 20 European installations by mid-2006, 15 of which are in the UK. The big appeal of the company's Serpentine ovens is the vertical, s-shaped path that the products take. This allows them to occupy typically one tenth of the footprint of an equivalent tunnel oven.

The company's latest initiative is to offer a version of the oven that swaps encapsulated trays for a system of finger carriers, which can accept a baker's existing trays. This means that potential customers can swap to a Serpentine oven without having to invest in other new equipment. Auto-Bake has already installed one of the ovens in a London bakery.

In contrast to the uphill battle that some suppliers are waging to introduce automation in moderate-sized bakeries, suppliers targeting the very biggest operations say that automation is essential. Alan Law, managing director of Schubert UK, says this enables the packaging company to buck the conservative trend and go all-out for a high-tech approach. "Our advantage is that we're looking at manufacturers who work at high volumes and high speeds. Our customers work multiple shifts, if not 24/7, so they need high volumes and high reliability," he says.

Law estimates that around two thirds of its business is already in the food industry and that portion of Schubert's customer base looks set to rise. "The market is expanding and it's partly to do with the [shortages] of people to do this kind of work." In one of its latest projects, for example, the company's equipment deals with 850 products per minute using just one or two people to monitor the entire packing line.

The installation at Greggs' factory in Long Benton near Newcastle-upon-Tyne loads frozen savoury products such as pasties and sausage rolls into transport trays ready for distribution to the bakery's retail outlets.

In the TLM-F44 line, a series of four-axis robots are fitted with special vacuum gripper attachments. These pick and place the products into several layers and insert a protective paper sheet between them. The automated packaging machine guides the transport trays through the system in several cycles in order to build up the multiple layers. A vision system monitors the various products for quality.

The line uses Schubert's operator control system to enable fast changeovers between different packaging configurations. "Dedicated machines demand a long set-up time, but with ours you just change the control panel settings and off you go again," says Law. "They could change the product every half hour and it wouldn't make any difference to our machine. And in the future, as markets change, it's just a matter of changing the programming and the system will be able to handle a different range of products. The investment won't be lost." FM