The Konsystograf is an instrument designed to determine rheological properties of dough, mainly wheat. The instrument provides measurement and registration of resistance of dough during mixing, which allows to determine, in particular, flour water absorption, dough formation time, stability, elasticity and dough softening.
Determination of such properties facilitates:
- classification of the wheat grain types used in baking in cereal cultivation stations
- composition of flour mixtures used in baking in mills
- management of technological processes in large bakeries
- research work in scientific and research units
The general-purpose konsystograf provides not only water absorption charts, but other characteristic charts determining features of the tested flour, such as:
- normal chart (This type of chart is made following determination of the flour 's water absorption, by adding the whole water amount to the tested sample to obtain and draft chart band using the instrument at 500 standard units drawn for 10, 15 and even 25 minutes on the recorder. The normal chart - also called the consistographic band - depicts dough behaviour during kneading, determining, in particular, dough development, dough stability, elasticity, softening (chart - band of the normal chart).
- resting curve chart
- fermentation curve chart
Dough development
Short times of dough development are characteristic for flour with poor gluten. Flour from soft wheat forms dough during 0.5 – 2 minutes, but from hard wheat during 4 – 6 minutes. Data on dough development time are very helpful in determination of kneading time of dough from a particular flour in bread production. The times of dough development in the konsystograf (faster) and in production kneading machine (slower) differ a lot and are difficult in terms of unequivocal determination because of the variety of industrial kneading machine types used in bakeries.
Dough stability
Dough stability is the time in minutes during which normal consistency of dough does not change during kneading. It is a measurement of dough stability and fermentation tolerance. Long stability time is characteristic for strong flour, where greater tolerance in determination of end fermentation time of dough is possible. Short stability points to the necessity of controlling the growth time and starting baking when growth is incomplete.
Dough elasticity
Dough elasticity defines the band width of the konsystograf (C1 – C2) and indicates extensibility and elasticity of the dough. Both these features in the kneaded dough cause frequent and fast changes in the resistance of dough against the mixing arms of the konsystograf. These variations are transmitted onto the drawing pen of the self-registering recorder which draws the band. The wider the band, the bigger extensibility and elasticity of the dough is. The wider curve – the bigger possibility of obtaining loaves of bread of higher volume.
Dough softening
Softening indicates weakening of the dough during the kneading process within 12 minutes. The obtained value is read from the chart band drop from the point of normal dough consistency, which is 500 standard units. It is caused by dough structure weakening, gluten bonds shortening and softening of the swelled gluten particles, which affects reduction of the resistance of dough against the mixing arms. When the softening value is high, dough should be kneaded for a short time and should not be brought to maximum growth of formed dough pieces and as a result flat loaves are obtained which are characteristic for sprouted flour.
The konsystograf can also be used for drawing a chart band, so called resting curve and fermentation curve.
Drawing up the resting curve is one of the methods used to determine enzymatic flour activity, which facilitates flour characteristics and its application for technological purposes with instructions on bread preparation. The band shape is dependent on the activity of flour proteolytic and amylolytic enzymes. The chart is made similarly to the normal chart; the record is cancelled when dough reaches the maximum dough consistency of 500 s.u. and renewing the record after one hour for 2 – 3 minutes and pausing again for 1 hour, so that distinct changes in the band chart are obtained, which practically lasts about 3 hours.
The Fermentation chart is drawn up similarly to the resting curve. However, the difference involves addition of a specified quantity of yeast (3 %) and salt (1.5 %) to the tested dough to obtain characteristic fermentation chart in conditions similar to the normal conditions occurring in the course of the baking process. It allows the evaluation and specification of the behaviour of dough during fermentation after each hour of chart pausing. It is expressed in minutes – it is the time of dough forming from the start of water addition into flour until reaching normal consistency of 500 standard units of dough. The development time depends on water absorption ability and flour constituents swelling, and above all the quantity and quality of gluten, as well as degree of milling, granulation etc.
Fermentation curve chart
a) dough resistant to fermentation, b) susceptible to fermentation
The Konsystograf is also used for testing processes of bread staleness. The chart drawing is preceded with determination of water content in bread and grinding the bread in the hammer mill for 1 second. A suitable amount of water is added to the weighed portion of the ground bread placed in the konsystograf's bowl to reach the mixture consistency of 500 s.u. When the required consistency is reached, the chart is to be drawn up for 4 minutes. The charts of such a type are made every 24 hours by taking new samples of the tested bread, and ensuring that quantity of dry bread mass and total water content must be identical, as for the first chart of testing the staleness of bread.
Technical parameters
- overall dimensions 500 x 350 x 630 mm
- oven power supply 380 V, 50 Hz
- weight 35 kg
- bowl capacity 50 kg
- removable spiral mixing arms
- power supply 230 V
- automatic burette
- automatic control
- graph record with recorder
Construction
- bowl
- recorder
- automatic burette
- water container
- machine drive
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