by Les Saidel - September, 2013

According to legend, prior to the battle of Borodino in 1812 between Napoleon Bonaparte and Russian General Kutuzov, the general's wife prepared a tribute to send with her husband into battle, a loaf of bread made with the local spice coriander. This bread (now known as Borodinsky Bread or Black Russian Bread), as legend has it, remained fresh and edible for a few weeks.

According to the Talmud, the Show Bread prepared weekly by the Levite family Garmu for use in the holy Temple, miraculously remained fresh (and warm) the entire week.

All of us have experienced stale bread, bread kept too long after it was baked. The outer crust becomes leathery and flaky and the inside crumb becomes hard and crumbly. Can the above stories be true? Is there a way to prevent bread from staling?

The scientific study of the staling process in bread has continued for the last 150 years, and while methods have been developed to retard staling and delay it, a means has not yet been discovered to totally prevent bread from staling. In this article I will present some tricks you can use at home to keep bread fresher longer, without having to resort to using potentially dangerous chemicals and preservatives, or buying products containing them.

Before we embark on this discussion we must understand the process of staling. I will try to describe it in layman's terms as much as possible despite the fact that the topic is highly detailed and intricate. Staling is a complex process that is only partially understood and more research is needed before we finally unravel all its secrets.

Basically the culprit that causes staling is the starch component in the flour. Starch is a complex sugar that exists in flour in microscopically sized round granules. Starch contains two polysaccharides (or sugars), amylose and amylopectin, the latter of which plays a major role in the staling process. In its natural state, amylopectin is crystalline in nature. When mixed together in bread dough, the starch granules soak up water and swell. During the baking stage, these starch granules continue to swell and eventually burst under the heat, finally gelatinizing to create the flexible, rubbery crumb structure of the bread we are all familiar with.

Immediately following the baking stage, the bread begins to cool and so too does the staling process. As time passes the amylopectin component in the starch begins to re-crystallize, the degree of crystallization being a factor of time and temperature. This process is known in layman's terms as staling.

For a time it was thought that staling was caused by migration of moisture out of the bread, making it dry and crumbly. It has been demonstrated however by research that even bread with a higher starting moisture level than regular bread, sealed in an airtight container still undergoes a staling process. It has been shown by scientific research that temperature is more closely related to staling than moisture level.

The longer time passes from baking, the more re-crystallization of starch occurs and the bread becomes "staler". The process of crystallization can also be accelerated by lowering the temperature. Crystallization of starch occurs most rapidly at 4 degrees C. Many people erroneously believe that by keeping bread in the refrigerator they are keeping it "fresh" for longer. In fact by keeping bread at refrigerator temperature (4-7 degrees C) they are actually hastening its demise.

There are two main ways to delay staling, one is by freezing and the other is by use of various additives to the dough.

Bread which is frozen may maintain is viability for many months. The way it is frozen and then defrosted however, is important in determining its level of freshness. As you freeze bread and then again as you defrost it, the bread passes through the 4 degrees C zone, twice. To maintain the bread as fresh as possible, the time it languishes at this temperature must be reduced to a minimum. It must therefore be frozen as quickly as possible. This is achieved by placing it in a low temperature, uncluttered deep freeze. If the freezer is cluttered it will take longer for the freezing process to occur and will lengthen the time during the staling temperature. During defrosting, the bread must be brought back to room temperature (18 degrees C or up) as quickly as possible. This is best done using a microwave oven (be careful not to overdo it otherwise you will "nuke" the bread).

When stored in a freezer containing only bread, frozen bread may remain viable for over 2-3 months. The problem is that in most homes, the freezer contains not only bread, but last week's lasagna, frozen broccoli and a variety of other goodies. Even if you seal the bread in a plastic bag, plastic is impermeable to water, but not to air and the bread will absorb the odors from the other inhabitants of your freezer. That is why, after about 2-3 weeks, your frozen bread starts smelling strange. This can be eliminated by separating bread into a freezer on its own and can lengthen the viability time.

Another tip for freezing bread, slice it before you freeze it. That way you can pull out a slice or two as needed, without having to defrost the whole loaf.

Another method to retard staling is by use of additives. These include addition of enzymes to chemically alter the starch structure and retard crystallization, by the addition of emulsifiers which retard staling, (although full understanding of this process has not yet been reached - we just know that it works), increasing the sugar level in the dough and by the addition of alcohols. These and more are some of the "tricks" commercial bakeries use to extend the shelf life of their products, unfortunately in most cases these are unwanted additions and not necessarily health building.

The only natural additive method of staling retardation is by use of sourdough, natural yeast, which produces, as part of its natural fermentation process, a small quantity of alcohols in the dough, or by adding lecithin, a natural emulsifier to the dough (at levels of 1% of the flour content of the dough).

One final trick to prevent staling is related to the temperature factor we mentioned earlier in discussing the chemistry of staling. If you reheat stale bread, you can "freshen" it up and it becomes quite close to the original product. The reason for this is that the heat reverses the crystallization process of staling and re-gelatinizes the starch. The caveat is that this can only be done once and following reheating, the staling process then proceeds at double the speed of the original first staling phase, so it is a one-time, short lived, quick fix.

As for the legends and stories at the beginning of the article, perhaps the Borodinsky bread remained fresh for up to a week (we have had similar experience with our own Black Russian rye - mainly due to its high level of sourdough natural yeast). However, a number of weeks seems a little far fetched, and while the bread perhaps remained edible after a month and did not go moldy (again due to the high acidity level of the sourdough), it was probably as stale as the hills.

As for the Showbread in the Temple remaining fresh and warm the entire week, we probably could provide some scientific reasoning for that, but we prefer to leave it at what it probably was - a miracle.

Les Saidel

 

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