A vacuum may usually be understood as a space entirely devoid of any matter, but it’s quite the opposite of emptiness when it comes to vacuum technology in bakery. What remains, in this case, is the perfectly baked and cooled bread and snack, ready to eat, with considerably improved properties – achieved in a fraction of the time and energy. The process is everything.
Particularly suitable for parbaked products, vacuum technology can cool breads, small baked items and pastries in a matter of minutes, while also stabilizing them for further use. The vacuum cooling process results in products with improved qualities and supports notable process optimization in terms of shorter baking times, reduced processing times and higher flexibility in the use of resources.
Cooling baked goods rapidly not only saves time, but it also comes with numerous other important benefits. It extends the microbiological shelf life of products, which drastically reduces contamination risks. Decreasing both pressure and temperature swiftly greatly reduces the window where mold or other bacteria could form – the 60°C to 30°C range, which applies to baked goods and other cooked items such as puddings, rice, or pasta. Furthermore, vacuum-packed products stay fresh much longer, as the crust contains more water than standard baked products. Products produced by vacuum conditioning not only have a longer shelf life at room temperature, but they are also crispier, more stable, and have a larger volume than frozen products. By cooling products in a controlled environment, inside the vacuum system, any fluctuations that occur in the ambient temperature are entirely eliminated. “This makes the production processes in the entire bakery more stable,” Koenig highlights.
In addition to improving product quality and extending shelf life, vacuum conditioning offers another decisive advantage when it comes to baking: it shortens the process. The extremely rapid cooling also means that bread achieves the necessary cutting firmness more quickly. This, in turn, allows the subsequent stages, such as packaging and delivery, to be carried out earlier.
Moreover, baked products that are frozen after vacuum conditioning can be consumed immediately after thawing and retain a crunchy crust and fluffy, airy crumb. This is particularly suitable for baguettes, brioche products with decorative sugar, bread rolls, pizza dough, or Mediterranean pastries (e.g., flatbread), according to Koenig specialists.
Vacuum and quality
The rapid pressure drop that occurs during vacuum cooling causes moisture within the crumb to evaporate instantly. “This internal movement of steam does not just cool the product – it also helps carry volatile aroma compounds from the surface deep into the interior. As a result, flavors are distributed more evenly throughout the baked good. Instead of aroma escaping into the air during traditional cooling, the vacuum process effectively ‘locks in’ these desirable notes, creating a more intense and harmonious flavor profile,” Koenig’s specialists underline. The result: vacuum-cooled bakery products with a richer and more intense taste, thanks to their enhanced stability, appealing volume, and the absence of wrinkles or ‘waist’ formation. The products present an open crumb structure and a pleasantly short bite.
The Austrian company developed its own vacuum cooling technology, packed into the QualityVac system. It can be designed with space for one to three racks and requires compressed air, fresh water, wastewater and electricity for its working principle: “The physical law that water boils at lower and lower temperatures as pressure decreases is the scientific basis for vacuum conditioning. The process utilizes this effect by extracting the energy required for the process from the product in the form of heat. Therefore, the product cools down in a very short time and is stabilized at the same time,” Koenig explains the concept.
A rack trolley with partially baked products is moved into the vacuum chamber, where the pressure is reduced employing vacuum pumps. The falling pressure causes water to evaporate, in the process cooling the products within a few minutes. The great news is that interim storage in the production facility does not require temperature-controlled enclosures; products can be kept at room temperature and can be baked to completion days or even weeks later, with virtually no loss of quality. An ideal scenario for in-store baking, for instance.
The QualityVac system can cool down products in the minimum amount of time: depending on the product, or the desired end humidity, 65 kg can be cooled in just 90 seconds, Koenig illustrates. Time is not the only factor vacuum technology improves; so is space: depending on the number of racks desired, the system needs only 5 to 12.5 sqm, which also includes the pump system. “Using a vacuum cooling system cuts operational floor space requirements by 50 to 70 %, removing the need for bulky cooling racks or spiral coolers,” Koenig observes. To achieve this compact footprint and operate in it comfortably, the QualityVac features a sliding door. What’s more, the door is adjustable, so it can be configured to slide from either side, according to the space requirements of each facility.
Vacuum and savings
During the vacuum conditioning process, baked goods lose crust moisture considerably, meaning that it no longer needs to be evaporated while baking, effectively decreasing the baking time. “Applied before baking, vacuum conditioning effectively replaces part of the second baking phase,” Koenig underlines. This makes the crust begin to turn brown considerably faster, reducing the remaining baking time by 20 to 40 % compared to conventional methods – a time that can be used to load the oven with the next products waiting to be baked. The QualityVac’s reinforced construction allows it to operate a very powerful vacuum pump, achieving faster vacuum curves and further shortening overall process times. The higher pump capacity also ensures the target end humidity is reached significantly faster.
“Using a vacuum cooling system cuts operational floor space requirements by 50 to 70 %, removing the need for bulky cooling racks or spiral coolers.”
Koenig specialists
In addition, the QualityVac is insulated with high-quality stone wool to minimize heat loss. The plate heat exchanger and water system are fully insulated with insulation panels and insulation tubing, so heat and humidity in the enclosure are completely controlled.
QualityVac and convenience
Koenig designed the vacuum cooling system to be ready to use within days of arrival at the facility. Altogether, the company allots 10 days on-site for installation, commissioning, and expert training, to ensure the system and processes are set to match the specific production needs of the operation. It comes as a complete solution, which can include features such as a cold water unit.
Koenig can also provide a floor-level model, which uses the same chamber and has an additional tray installed underneath. This version features a floor drain to allow water to be conveniently removed.
It’s also easy to operate, via its touch screen menus, with 50 program steps built in, which can be saved for custom programs. Koenig offers training for operator teams, as well as remote maintenance, so its specialists can inspect a unit in real time if needed. All vacuum curves can be fully customized and freely programmed. Moreover, the chamber is equipped with integrated lighting for convenient operation
A matter of safety
The QualityVac incorporates operational safety features, which extend the intervals between service appointments. For example, its screw pump, which is the ‘vacuum generator’ as it traps and compresses gas between screw rotors, is built with ceramic-coated compressor screws to prevent the compressor unit from rusting and getting blocked, which could be caused by condensate. In any case, the screw pump can be easily removed for maintenance. “It provides higher system availability and a longer service life, as the ceramic coating prevents overheating, eliminates radiant heat, and minimizes heat transfer. This significantly enhances the durability of the entire installation,” the system’s developer details.
For safety, the vacuum chamber is equipped with two emergency stop buttons. One of them is located on the outside of the control panel, and the other inside the vacuum chamber. “In an emergency situation, these emergency stops can be confirmed. All processes within the vacuum chamber stop immediately,” Koenig explains.
Maintenance needs are also optimized: “The robust chamber construction ensures long-lasting, corrosion-free operation,” Koenig points out. So much so, that the QualityVac is designed for virtually maintenance-free operations. In the machine’s maintenance manuals, Koenig recommends controlling components such as seals, the pneumatic unit, drive components and checking the gearboxes for leaks, monthly.
The specialists point out: “Its chamber-integrated heat exchanger is our own in-house development. The plate heat exchanger allows full access for maintenance and cleaning; and no component replacement is required even after extended operation.” For easy cleaning, the system features a removable stainless-steel grate.
The pump is operated oil-free, for an extra step in safety and hygiene. Its self-balancing screw design ensures the lowest possible vibration level and low-sound operation. Additionally, the screws are manufactured from a single-piece casting, eliminating any gaps. “This makes an ingress of process fluids or particles impossible and thus, corrosion and deposition are prevented.”
Developments in the field of vacuum cooling technology
Koenig currently offers a rack-based solution, which can be provided as a single rack and can go up in operating volume to three racks. The R&D has not stopped with these customizable models, as futher automation is in the works for large-scale operations, the company reveals. “We are already developing a fully automated industrial system for continuous vacuum cooling. This tunnel-style setup eliminates waiting times entirely and ensures a seamless, uninterrupted production flow. The reason for this development is that we see an increasing demand for fully automated processes,” Koenig anticipates.