Features Technical
Tricks of the Trade: November 2012

Determining the difference between undesirable holes and alveoli in bread.

Determining the difference between undesirable holes and alveoli in bread. In the crumb of our artisan bread, we often find big holes, or open crumb. With this in mind, let’s first make the necessary distinction between undesirable holes and alveoli in the bread.

Open crumb full of alveoli is normal in ciabatta bread, but the presence of alveoli is not acceptable in sliced pan bread.

Holes often appear as tunnels. When we cut the bread, we find the same hole on several slices. Alveoli are more evenly distributed everywhere in the crumb. Open crumb for artisan bread is normal whereas holes are not acceptable in the sliced pan bread.

The question concerning artisan bread is whether or not it is normal to have what we call an open crumb that is full of alveoli, or big cells. People commonly refer to these as holes. Their presence in sliced bread is one of the problems that leave bakers and industry experts most perplexed. There are many possible explanations for holes in the breadcrumbs, but the defect may also be a combination of two or more of these causes.
Mostly, bad shaping causes holes:

• If shaped by hand, there may have been insufficient pressure, causing the dough piece to be insufficiently degased.
• The rollers of the moulder machine may be damaged or in bad shape.
• There was an excess of flour during the shaping.
• If the inside of the holes are shiny, it is possible that too much oil was used. Because this divider oil is mineral and does not adhere to the dough it will form a hole.

The intermediate fermentation period between the weighing and the shaping is too long for the strength of the dough. Dough that is too old or too warm may cause this problem, as can improper mixing (dough under- or overmixed).

Lacking humidity in the steam room (proofer) will cause holes. If the fermentation is made in wooden boxes, make sure that boxes are closed well one on the other to preserve the humidity of dough in the box. If the dough gets a dry skin, it imprisons gases and forms holes.

If holes are under the crust it is possible that the proofer is too warm. Dough that ferments too fast will tend to have holes in the finished bread. A too-long fermentation time gives wide alveoli, which we mistake for holes.

Dough that is too hard or too firm will form holes; dough that is very soft and well developed will form alveoli.

Baking bread in an oven with too low a temperature provokes a continuous development, because the yeast rises too long before being seized by the heat thus creating holes.

An abrupt manipulation while putting bread into the oven can cause holes. If the cellular structure of the bread collapses it cannot swell again, which can create a separation of the crust and a big hole.

The use of too much improver or too much oxidizer will make dough more difficult to flush out the tanks during the shaping, which will cause an open crumb.

Pay attention at all stages of manufacturing and you will probably find the reasons for the unwanted holes in your bread. Just remember that people are looking for holes (alveoli) in artisan breads. They expect open crumb or large cells in ciabatta, for example. The high absorption (80 per cent) with good mixing will guarantee you a consistent result in these breads.

Mario Fortin is an international bakery consultant and owner of FORMA-LAB, consulting services to bakers and suppliers. If you need technical information, send your question to info@forma-lab.com.