The core product can be of various types: poultry, cheese, fish, vegetables, and fruits.

The batter is prepared with the following:

• Wheat flour
• Finer flour (maize, rice, tapioca) or native starch of the sort
• Functional starch with expanding, binding, filming, and barrier properties
• Active ingredients (proteins, hydrocolloids)
• Fats
• Leavening agents
• Flavour and colour
• Salt, spice
• Water

The dry ingredients are first mixed, then the liquid is added. To avoid lumps, progressive liquid addition, and thorough mixing are required. The mix is prepared and stored at a low temperature and kept agitated. The choice of ingredients will determine the thickness and expansion.

In the case of prawn nuggets, the coating is very thick; in the case of French fries, the consistency is excellent, providing a barrier effect and retaining crispiness longer. After the liquid coating, the product is dusted and sprinkled with fine to coarse particles: breadcrumbs and Japanese crumbs.

The operation occurs in a series of machines: Flour duster, optionally, Batter coater, and Breadcrumb coater.

The choice depends on the product type (size and shape) and the rheology of the coating ingredient mix (fluid/bridging, fine/coarse, fragile/resistant). The combination of machines depends on the recipe and number of operations.

Selecting a system requires doing the test during which one observes the product motion during the application and its results, the behaviour of the ingredient mix, the recycling efficiency, the pollution, and potential hygiene hazards—picture courtesy of Barsso NV.