Dough extrusion is a forming operation in which bulk dough or highly viscous batters are transformed into single pieces that can be immediately baked.

Dough Extrusion

What is Dough Extrusion?

Dough extrusion is a forming operation in which bulk dough (usually sweet or rich) and/or highly viscous batters (relatively high in sugar and fat, and with very low hydration levels) are transformed into single pieces that can be immediately baked on a continuous biscuit oven.1

Baked goods that are made using dough extrusion include:

  • Pastry products (laminated prior to forming)
  • Soft cookie doughs (wire-cut cookies, swirl-type cookies)
  • Filled and two-dough cookies (co-extrusion of fillings using concentric dies)
  • Whole grain bread from sprouted wheat “flourless” dough

How does dough extrusion work?

Dough extrusion is a process in which dough material in bulk is forced to flow, under pressure and shear, through a shaped die (orifice) and then cut to obtain a single piece of product of desired form or dimensions.

It is important to note the term “dough extrusion” in the bakery industry refers to a cold process. Cold extrusion is the forming of dough materials at temperatures below 40°C (more specifically below melting point of fat). This processing concept differs from “extrusion cooking” technology used in the snack industry and conducted at temperatures above the boiling point of water (212°F or 100°C) in which steam (water vapor from product) is formed.2

Components of a dough extruder3,4

1. Inlet hopper

A hopper is placed over the feeding or dough driving mechanism. The hopper holds the dough load coming from the mixer and becomes a balance tank. Hoppers have a special conical configuration, using gravity to convey the dough downwards.

2. Feeding or driving system

Two or three rollers force the dough into a “pressure chamber” that is located just before the die. The rollers run continuously (at low rotation speed that can be locally adjusted) or intermittently to force dough out of the pressure chamber at the die. In other systems, a single- or twin-screw feeder is used for handling different product rheology and consistency.

3. Die or nozzle

A die, nozzle or orifice, function as the final forming mechanism. Different diameters, shapes, configurations (e.g. concentric) and construction materials can be used, depending on the rheology and stickiness of the dough, product filling needs and desired form of the finished product.

4. Cutter and depositor

For production of wire-cut...

To access the rest of this page, you must be a member of the American Society of Baking.