A number of years ago, several bakers tried, unsuccessfully, to adapt microwave tunnel ovens to the baking process. But as is commonly known, there is no surface heating and drying to produce the browning reaction. Impingement Ovens have been used for many years in meat processing as well as the standard for pizza cooking. These ovens use very intense, high velocity air impinging directly on the product and with a heat transfer equal to 5-25 times greater than natural convection. This technology offers gains in speed and reduced oven size, while maintaining proper surface color.
Dielectric heating is a newcomer in the commercial market.
The moisture in the product really becomes the heat source. A very new technology, still in the early stages of acceptance, uses an electrostatic phenomenon. Recognizing that various heat transfer systems all have different properties for different products, the current thinking is that if multiple technologies were linked together in a reduced-size, flexible system, one could have optimum baking with the greatest production flexibility. This approach allows the larger, regional wholesale bakery to have a closer quality match to in-store bakeries. Hybrid oven technologies allow for this flexibility and versatility, but are still in the early development stages.