糖粉或砂糖粉
在混合器中方便地处理的大量物质现在进入了真正的
精制。通常，该方法可以通过两种不同的方法进行：使用粉末糖或砂糖。在第一种情况下，我们将直接在“五缸”（一个阶段过程）中，而在第二种情况下，将有一个粗略的第一步是在“两个圆柱”中粗略，然后在“五缸”中（两阶段过程）。应该记住，在可可后，糖是巧克力最重要的成分，因为它至少为组合物的40-50％。根据其物理状态的选择取决于单一阶段或两个阶段采用精炼技术：在实践中，我们必须决定我们是否通过预先炼油来进行。如果我们想要排除预炼油，则需要部分地将颗粒中的颗粒中的颗粒中的颗粒（Pre）磨削，使其在该过程结束时，它将具有非常低量的细颗粒（子粉）因此不要影响随后将改进产品的产物的流变特性：我们具有更精细的颗粒，将巧克力层压更多的脂肪。在研磨过程中，需要注意热敏的糖，因此可能存在自发燃烧和爆炸的风险。相反，如果我们预先精炼，巧克力物质在混合器中制备后，将通过两个或三个气缸，这将减小颗粒的尺寸，使得它们均匀地适合精制到“五缸”中。得到的质量比来自混合器的块更密集，它将被传送到下一个精炼阶段。 From a physiological point of view, human taste buds allow particles not smaller than 20–25 µm to be discriminated, which means that only particles with bigger dimensions can be recognized as “grains”, giving roughness sensation, which is a well-known feature of not perfectly refined chocolates. So, apparently, from the technological aspect, one should ensure that all chocolate particles have a maximum size less than 25 microns. However, the taste sensation doesn’t depend only on the size of the single particles, but also on their uniformity of distribution. Refining machines are, in essence, machines formed by a certain number of cylinders, from three to five, initially made of granite, currently made of centrifuged steel, coupled in longitudinal direction, with devices that, applying forces at the cylinders’ ends, are designed to delimit the distance between them (lights) when the product passes through. The work surface – refining table – is in practice determined by the cylinder’s length. Water – usually cold or mild – circulates inside the cylinders with the purpose to balance the heat generated by the friction caused by their movement and by their action on the product. The mass passes from one cylinder to another, from the lower to the respective upper cylinder, running them all until its pouring out, which occurs by scraping the upper cylinder. The mass inside a refining machine must be perfectly homogeneous so that its passage through the cylinders is constant, in other words, some phenomena such as fat separation that causes discontinuity in the product processing must be avoided. Generally, the fat content of the masses to be refined ranges from 22 to 30%, which means that, from similar grain sizes, the rheological characteristics of the same may vary from the condition of “dry sand” to very liquid dough. During refining, the product’s sliding characteristics vary considerably, to the point that at its pouring out, we get a dusty-looking product. During refining, grinding is determined both by crushing, due to the forces that delimit the opening of the product’s passage between the single pairs of cylinders, and by the fact that these rotate at increasing speeds from first to last (from the bottom upwards), generating considerable cutting efforts that, when they are raised up by the very small amount of product on which they apply, they surpass the power of the particles’ internal cohesion and cause their breakage. Transfer of the product from a cylinder to another, is practically due to the different existing speed, which in turn, must be carefully calibrated to allow the passage of the whole mass that has crossed the grinding opening. This aspect highlights how the refining process is essentially controlled by the speed ratios existing between the refining machine’s cylinders and by the forces applied on the cylinders that delimit the grinding opening. In conclusion, the refining process can be described through the description of the interaction phenomena existing between the mechanical settings of the machine, by defining the applicable parameters as – for example – rotation speed, the entity of the forces that delimit the opening and the rheological characteristics of the product to be processed, in their turn determined by composition. A further control parameter that regulates the machine’s operating is given by the cylinders’ temperature, which causes, in practice, an easy or less easy cohesion of the product on the same cylinders: if we increase the cylinders’ temperature we will reduce the chocolate’s adhesion on them.
