Did You Discovered Extensograph?

An extensograph is a tool used for measuring the flour quality and stretching behavior of dough. Extensional properties, which determine the course of dough expansion during proofing and baking, have a direct effect on:

? Loaf volume

? Quality of texture of bread crumb

Function

Information on the extensional properties of bread dough is read directly from the diagram of the extensograph curve, also referred to as the extensogram. The extensogram represents changes in resistance, also called the strength, of the dough to extension (R) as a function of the extension distance (E). See figure 1 comparing a strong gluten dough to a weak gluten dough

Figure 1

Resistance to Extension (R) is indicated by the maximum height of the curve and measured in centimeters, Brabender units (BU), or Extensograph units (EU).

Extensibility (E) is indicated by the length of the curve. It is measured in millimeters or centimeters.

R/E Ratio indicates the balance between dough strength (R) and the extent to which the dough can stretch before breaking (E).

Area Under the Curve is a combination of resistance and extensibility. It is expressed in square centimeters.

Process

A sample of flour- water-salt dough pieces of constant weight and of the appropriate water absorption are prepared using the Farinogrph. The Farinograph measures flour- water absorption and dough strength.

The dough piece is rounded and molded into a cylinder under constant conditions. Each piece is then pegged into a cradle and allowed to rest at a controlled temperature. The piece is extruded by a hook which travels downwards at a constant rate. The load on the dough piece is recorded and the extensograph curve is obtained.

Application

Results from an extensograph are useful in determining the gluten strength and bread-making characteristics of four. Changes to formulas such as fermentation time, type of flour or new supplier, dough additives can all be evaluated by an extensograph.