The equipment originally used to produce caramel cooler and toffee was a simple gas or coke-fired boiler. The technology was the same as described above for the experimental preparation. Many pastry chefs believe that heating by gas or fire is the only way to get true caramel flavor/aroma.
Later, fire heating was replaced by steam jacketed boilers. The technology remained intermittent and the caramelization was still good. Some firms, frustrated with continuous processes, mechanized batch production with multiple boilers and piping.
Nevertheless, the study of the original batch process showed the importance of the time factor in cooking.
In continuous processes, a caramelizer is currently used that allows the continuously produced milk candy to be passed through a heater for about 20 min at a temperature close to the final boiling point of the milk mass. This allows for good caramelization.
Especially convenient for fudge production is the tray cooler, where the fudge is extruded into a cooling tray. Such a method yields a different product, and it is important to realize that fudge pieces cut from a plate prepared by the above-described boiler method are characterized by brittleness, while the continuous process (especially with extrusion) yields a softer paste.
In the case of the continuous process, it has been found to be beneficial to use a fondant with a higher sugar content – a sugar to glucose syrup ratio of 10:1 instead of the usual 4 : 1 or 3:1.
There are also different designs of heat exchangers, thin-film and with cleanable surfaces. If you intend to use these digesters for the production of milk candy masses, you must take into account the possibility of burning films of milk products on the surfaces. In this case, heat transfer is significantly reduced and dark particles may appear in the final product. The removal of these films is a complicated process that requires filling the cooking apparatus with concentrated alkali solutions and washing them thoroughly.