The suitability of rye varieties for baking in Germany is generally
tested with the German flour types 997 and 1150. But standard baking tests with
wholemeal rye flour can be carried out with "Falling Number meal".
For bread made of mixed wheat and rye flour, Neumann and Brümmer (2000) have
suggested "basic baking tests".
Besides the practical baking test with sour dough there is also a
baking test with yeast, without any acidification, and a further test is
carried out with a standardized addition of lactic acid depending on the
mineral content of the rye flour to be baked.
The most important attributes in the baking test with sour dough are
dough yield and dough properties, volume yield, pore structure, elasticity of
the crumb, purity of taste, and the flavour potential resulting from the sour
dough. The results of the tests are used to calculate a Quality Number. For the
mills, especially, this offers excellent possibilities of describing the
quality of their flours.
6.2.1. Dough Yield and Dough
Properties
Dough yield22 is an important economic factor. At the same
time it has a considerable influence on the processing properties of the dough
and the quality of the rye bread. Indirect processes (sour dough) and direct
acidification (with dough acidifiers) require different amounts of ingredient
water. In the direct process the amount required is about 4 to 6 parts greater,
depending on water-binding capacity and the nature and quantity of the dough
acidifier. The water added must be sufficient to enable easy (usually
mechanical) processing of the dough. At the same time there must not be too
much release of water during baking, as this might weaken the crumb. A possible
overdose of water is manifested in very soft, moist crumb and often a
horizontal separation of the crumb from the crust, whereas vertical cracks in
the crumb of loaves indicate that too little water has been added. They may be
caused by dough that is too firm, by inadequate gelatinization of the starch or
by excessive water loss during baking. To determine dough yield in the sour
dough baking test, Brümmer (1988) has published a Farinograph method that can
also be used to determine the amount of water to be added in the standard yeast
and lactic acid baking tests. Nevertheless, a constant water addition of 73% is
still generally used in these two special standard baking tests, although it is
less in keeping with the raw materials.
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| Fig. 94: Comparison between the values for indirect methods and dough
yield in the baking test with rye flour and sour dough (German harvests of 1999
- 2002) |
To some extent dough behaviour can be predicted by the swelling curve
(Drews, 1971a, b). The curve shows that the degree of softening and thus the
dough yield and dough properties do not correlate with the Falling Number, the
Amylogram and volume yield (Fig. 94 and Fig. 95).
 |
| Fig. 95: Comparison between volume yield and dough yield in sour dough baking tests with rye flour (German harvests of 1999 - 2002) |
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