Buying your leaven
natural leaven and baker's yeast
The dehydrated leavening agents found commercially are usually sold under the appellation " baker's yeast".
The name in it's mediocrity is deceptive.
If it is not called "dehydrated natural leaven", then naturally it consists of somthing different!
For a proper understanding, it is useful to recall that leaven is a flour/water paste containing a culture (living micro-organisms), capable of converting the fermentable sugars in the dough into carbon dioxide.
Leaven can be said to be "natural leaven" only when the flour and water mixture is transformed into a living culture because of the spores and bacteria found in the air naturally.
For bread-making it is these leavens and these leavens only that interest us.
Their naturally complex composition ,formed by the numerous origins of yeasts and bacteria present in them, gives the bread a full flavour.
(If a leaven is not marked "natural" then it could well originate from a packet of baker's yeast simply added to a flour/water medium.
Little benefit comes from using such a leavening agent for bread-making because no complex structures will enter into the fermenting process).
On the other hand the flavour and conservation of conventional,industrial bread suffers fom the use of yeast that issues from the same origin, chosen for the strength of its raising agent.
To compensate for the lack of flavour in bread baked using baker's yeast, sometimes your conventional or industrial bakers will use inactivated leaven,known as "starters" (whose cultures,having been destroyed by high temperatures,and do not enter the process of fermentation).
The composition of "baker's yeast" is more or less always the same.
It is made up of a yeast (sometimes a natural leaven) that has been dehydrated; sometimes inactivated (the cultures are killed by high temperatures) ;and to this is added 20 to 30% of dehydrated baking powder ( known as bread-raising agent).
The leavening agents ,confronted with such a large dose of raising agents, are unable to develop significantly!
The result is we have a bread baked with a raising agent.
The dehydrated leaven used at the beginning of the bread-making process is a mere flavouring. (Starter).
The use of "baker's yeast" imitates the methods used by conventional and industrial baking. Basically the bread is made using a raising agent,and it's taste is slightly modified by a flavouring: the inactivated leaven.
The resulting bread is bound to be mediocre. Bread baked with natural leaven is far superior and so simple to make..
For your information, the composition of "baker's yeast":
Mark:Priméal/ COMPOSITION: inactivated wheat leaven issued fom natural fermentation, bread raising agent.
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