Baking Industry transforms with Vacuum Cooling
Announcement posted by John Morris Group 09 Nov 2015
For thousands of years, few things taste as satisfying as freshly baked goods: the crisp crust on a loaf of bread or sweet flaky pastry that melts in the mouth. Thanks to commercial bakeries, such pleasures are now accessible virtually anywhere.
Over time, the baking industry has introduced many innovations. Whether machines to mix and form dough, environmentally controlled proofing cabinets to prepare loaves, or convection ovens that help the baking process by circulating hot air, technology has made production more cost effective and efficient. Now the world is seeing the newest evolution of baking with the introduction of vacuum cooling, which can speed preparation, reduce energy use, increase efficiency, make the baking process safer and improve the quality of the baked goods all at the same time.
The baking process stretches back to 30,000 B.C. with the first appearance of flatbreads. Bakers labored at their ovens and worktables recorded nearly 8,000 years ago in the Middle East and Turkey. During the Roman Empire, baking as a profession really came into its own. As with any industry, innovation and the desire to better satisfy customers both in quality and quantity came into play. With electricity, motorized mixers eventually freed bakers from hand mixing and kneading. Pre-sliced bread first appeared in 1928. Convection ovens, unknown before 1967, are now a staple within most bakeries because they speed up baking with more consistent results, .
Baking innovation
The newest evolution in baking is the introduction of vacuum cooling. "One of the thorniest problems that commercial bakers face is waiting, after baked goods come out of an oven, before they can be packaged and shipped," said Klaus Buhlmann, Market Segment Industry, Oerlikon Leybold Vacuum. Bread and pastries typically bake at temperatures from 175°C to 220°C. Whether fully baked and intended for retail packaging or partially baked and frozen for later final treatment, these goods are literally too hot to handle straight from the oven.
Bakeries require cooling racks and shelves ,to handle baked goods, until they have reduced in temperature and may be packaged. The process in large-scale baking operations often involves intensive cooling equipment to bring goods to a finished state and that process involves significant energy costs. Because the wide variety of breads and pastries require a varied range of cooling times, managing production schedules and processes gets complicated. "Even in vertical racks the products take up extensive floor space, increasing substantial expense to meet real estate requirements," said Buhlmann.
In addition, the cooling process itself is one fraught with danger. As the baked goods drop in temperature from 60°C to 30°C, they enter conditions that are optimum for the growth of mould. Bacteria also has the potential to grow. The longer any products sit, the greater the chance that they might be infected. Prolonged higher temperatures can also aid the formation of such processing contaminants (PCs) as acrylamide or hydroxymethylfurfural (HMF).
Problem
Cooling products is a big challenge for the baking industry, whether from a healthly point of view, expense or processing complexity this is an issue.
Bakers' Solution
Bakeries can now be equipped with a new tool, based in basic science enabled by advanced oil-free, screw-type vacuum pumps with integrated frequency converters, allowing pumps to operate at the high speed necessary for fast evacuation.
Putting science to work
Vacuums turn out to be extraordinarily useful when cooling foods. There are three ways objects lose heat: convection (movement of a liquid or gas that transfers heat from one place to another), conduction (direct transfer from physical contact) and radiation (emanation of infrared radiation). Breads and pastries aren't particularly good at radiation or conduction. Convection requires time, space for air to move to, and energy to pump the air and possibly chill it to enable faster cooling.
The dynamics change in a vacuum. Most people learn in school that the boiling temperature of water falls as pressure is reduced, typically from being at higher elevations. At surface air pressure, which has a measurement of just over 1000 millibars, water boils at 100°C. Reduce the pressure to 42 millibars and the boiling point drops to 30°C. For baked goods, which need to have water evaporate anyway to avoid products becoming soggy, a vacuum chamber drastically reduces air pressure, causing the water still in the hot products to boil and evaporate, carrying heat with them. Rather than taking as long as several hours to reduce the heat, cooling times drop to between two minutes and six minutes to reach 30°C.
Because of the short times needed, vacuum cooling offers an amazing set of benefits. "You can reduce the actual baking time by 25%," said Adolf Cermak, founder and CEO of Cetravac AG, a Swiss pioneer in modern vacuum cooling. The removal of moisture through the vacuum conditioning process performs the function of that last fourth of baking time. That means 25% less energy used in baking.
In addition, the vacuum cooling and conditioning extends the time baked goods remain crisp (without softening) by six to 12 hours because of the amount of moisture that can be removed. Goods come out better, with crisp crusts and even, loose crumb that maintain volume and stability. An artisan bakery in Germany with 30 shops, for example, used to depend on par-baking goods at a central location and then finishing them at the individual stores because breads or rolls, baked at 2am, would normally have been soft when they arrived at the shops. Each shop would need at least one employee on duty 1.5 hours early to finish the baking of the products with a minimum wage of €8.5. That is a daily cost of €382.5 that can be eliminated.
Additionally, the short time spent in the 30°C to 60°C temperature window means that goods are safer, less likely to suffer premature spoilage due to mold or processing contamination and no longer in need of an additional costly sterilization process. These systems can save up to 90% of the floor space that would otherwise be needed. Bakeries can use so-called pre-baking, in which goods are partially-baked in central facilities, vacuum cooled and then delivered to retail locations. Vacuum processing allows storage of products for up to four days. Goods are then finished off in ovens at the locations. Logistics and storage costs are reduced: depending on plant design, cost reductions can reach 50%. The result: crisp and fresh croissants, baguettes, brioche with raisins, and other delights waiting on shelves for customers.
But the successful application of vacuum cooling to food processing, based on advanced vacuum solutions by Oerlikon Leybold Vacuum, is hardly limited to bakeries. Already sushi producers are using it to cool rice. Virtually any type of food that needs cooling before delivery can benefit from the technology.
Article originally published by Oerlikon.com