Natural yeast or chemical yeast?
- Natural yeasts: they produce biological leavening, thanks to the intervention of organisms of a microbial nature, they are real living yeasts and bacteria. The latter, thanks to the fermentation process and the activation of heat, metabolize the carbohydrates, thus producing acids, alcohol and carbon dioxide. In this category, we find brewer's yeast (dried, fresh, powdered), and sourdough. Brewer's yeast is not a bacterium, but a fungus called Saccharomyces cerevisiae and produces only an alcoholic fermentation, while we will see that the sourdough is made of many microorganisms, such as lactic ferments, absorbed from the environment.
- Chemical yeasts: these are dry leavening agents used to increase the volume and lighten the dough of bakery products. As the adjective "chemical" indicates, these yeasts are nothing more than combinations of one or more salts that produce carbonic gas through an acid-base reaction. The word yeast, in this case, refers only to the action of "removing". Chemical yeast: compared to biological yeast, chemical yeast has a shorter leavening time (a few minutes compared to hours) and no metabolic transformation of carbohydrates into ethyl alcohol, carbon dioxide, water and volatile compounds in general. They are not "dangerous" or unnatural agents, as you might think, but simply inert mixtures (for example tartaric acid or sodium bicarbonate) which, activated in dosed combinations, can quickly release carbon dioxide, but also have limited leavening effects.
How mother yeast is born and how it works
Certainly, the Egyptians did not know the fermentation process and believed that this reaction was completely magical. In fact, even today it might seem a miracle that the history of sourdough is made of just two ingredients: flour and water.
In recent years, we have seen a return to slow and natural leavening, along with food trends and the philosophy of self-production.
Mother yeast vs. brewer's yeast: benefits and advantages of using mother dough
Bread has a more acidic taste and a denser texture than brewer's yeast, but still well pored.
Advantages of preservation
- Lactobacilli, which are responsible for the acidity, also slow down the aging of the bread texture and its deterioration. Bread with sourdough can be kept for more than a week. The brewer's yeast and its faster alcoholic fermentation give a well-pored crumb, but it hardens much faster.
- The acidity also protects against harmful moulds and microbes. Bread with sourdough does not mould.
- The glycemic index is lower than for brewer's yeast bread: bacteria digest sugars and transform them into other substances (such as CO2).
- Mother yeast pre-digests bread. The longer leavening times required to allow enzymes more time to break down proteins (such as gluten), lipid and starch macromolecules, into simple nutrients. A product obtained with sourdough is, thus, more digestible.
- Sourdough is considered a probiotic to ease intestinal swelling problems associated with the consumption of leavened dough. On the contrary, brewer's yeast is not recommended in these cases (the effects are amplified by incomplete leavening or insufficient cooking of the product).
- Baking with sourdough allows the body to benefit from the properties of minerals present in whole meal flours. The higher acidity produced by sourdough more easily activates the enzyme phytase which neutralizes the action of the phytic acid present in the bran of the cereal. Phytic acid is practically an "anti-nutrient" that prevents the assimilation of certain minerals such as calcium, iron, magnesium, and zinc.
Mother dough: where can I find it?
- Mother dough and its unique aroma are the signatures of the baker who wants to express its full potential. Choosing sourdough, as a consumer or producer, means choosing slowness, believing in a sustainable bread supply chain, looking for quality raw materials and organic products.
- Mother pasta is more than anything else a symbol of conviviality and a means of rediscovering traditions, the role of craftsmanship, the enhancement of production at the forefront of consumption. That's why today many people try their hand at the recipes that are so popular on the web, to create with sourdough, not only bread but also pizzas and cakes for all tastes, with extraordinary varieties of taste, nutritional and conservation properties.
The sourdough is a live product and must therefore be maintained regularly. We therefore talk about continuous "refreshments" that allow to invigorate the yeasts, that is the addition to the dough of other flour and water in a precise quantity.
Today, real naturally leavened bread is rather difficult to find, because new baking yeasts reduce preparation times and costs and only some bakeries are specialised. It should be noted that the term "natural leavening" may include a production with brewer's yeast (also, as we have seen, is a natural yeast). Mother yeast can be found in two forms: solid and liquid. This last variant, which is gaining a lot of ground in the home and professional field, has a higher percentage of water than the solid form and is easier to maintain.
Making homemade bread with mother yeast
Putting your hands in the dough is a matter of Zen, try it to believe. And the yeast? Nothing could be easier to find or do at home. Always starting from the principle that the sourdough is obtained by the fermentation of water and flour (and time), without the need to add anything else. Otherwise, you can look for mother yeast "dealers", a network of bakers and bread lovers, who give a dose of yeast grown and maintained, to anyone who wants to make a healthy bread, along with good tips for baking.