By Eva Sacchi Hunter, Nutritionist
Natural yeast, or sourdough, is a mixture of water and flour in which bacteria and lactic ferments are present. Products made with natural yeast are more digestible, free of artificial additives and better tolerated by diabetics. Let's find out better
What is natural yeast
Also known under other names like sour yeast, sourdough, sourdough or growing pasta, natural yeast is rediscovering a renaissance in the world of bakery and pastry.
It is a mixture of water and flour in which bacteria and lactic ferments are present which, over countless days, allow the start of fermentation of the essential doughs for the preparation of some types of bread and cakes (for example panettone, pandoro, and dove). Unlike brewer's yeast, consisting mainly of colonies of Saccharomyces cerevisiae, in the yeast there are several species of Saccharomyces and Candida as well as various lactic bacteria of the genera Pediococcus, Leuconostoc, Lactobacillus and Weissella .
Our body is rich in millions of bacteria that help us live and those in mother yeast are part of the family of beneficial bacteria that help keep our body in harmony and balance .
The growth of natural yeast and bread is based precisely on these yeasts and bacteria present in the flour and on their work of decomposition of starch and sugars to feed on them. This decomposition leads to the formation of carbon dioxide and alcohol (ethanol). The carbon dioxide is then imprisoned by the gluten (proteins) of the flour and with the heat it expands making the yeast and the bread increase in volume.
Properties and benefits
Compared to the production of breads and sweets with yeasts used in large-scale commercial bakeries and pastries, the production that uses natural yeast requires a considerable number of more fermentation hours, as well as a superior ability, and the result is a product rich in holes, with an elastic and compact crust, with innumerable health properties .
Yeasts naturally present in flour are much less concentrated than commercial ones and for this reason they are better tolerated by individuals who react unfavorably to the excessive contents of yeast present in the most commonly available breads. Consequently, among the benefits of the sourdough I am certain to consider the better tolerability and digestibility .
The slow fermentation also allows the growth and development of beneficial bacteria (lactobacilli). These bacteria produce lactic and acetic acids, and it is these acids that preform a considerable number of beneficial functions:
- allow the body a greater absorption of essential nutrients such as calcium, magnesium, iron, zinc, antioxidants, folic acid and other B vitamins;
- reduce the level of phytic acid;
- they modify or eliminate the protein particles that can trigger wheat intolerance and celiac disease;
- they act as natural preservatives; produce amino acids and γ-aminobutyric acid (GABA) able to improve the nutritional value of the products. For example, in 150 grams of Pane di Matera PGI provides the minimum daily dose to decrease the pressure in moderately hypertensive individuals.
In diabetic individuals, bread made with natural yeast causes a lower increase in blood sugar levels and a lower production of insulin, thanks to a glycemic index equal to half of the traditional bread. Gluten is completely decomposed and therefore is virtually harmless, causing no problems for coeliacs.
Generally, products made with sourdough are free of artificial additives, commercial yeasts, emulsifiers, acidifying ingredients, preservatives and a wide range of enzymes often added to bakery products made on an industrial scale.
Naturally leavened bread also generates a greater sense of post-meal satiety and its acidity guarantees a lowering of the pathogenic content of food micro-organisms with a beneficial effect on the intestinal flora.
You can also explore the properties and uses of brewer's yeast
How to use it in the kitchen
The sourdough yeast has a different composition, based on the initial cultivation, the lactic acid bacteria present, the yeasts, the origin of the flour, the environment, the temperature, the duration of the fermentation, etc. Each crop will therefore be different and will always give the bread a slightly different taste.
In any case we start from a fist of fresh and raw dough of whole wheat flour and water, left to ferment for days and pressed, and after a few days stored in the fridge. In the end this sourdough yeast will be very hard and dry, with a strong and distinctive odor.
Before being used, this pasta must be crumbled, softened, dissolved without lumps in warm water, and fermented again, ie revitalized, with the addition of new flour. This revitalization process must be done several times over several days, until a fermented and blistered mass is obtained that can finally be used to make bread.
Sourdough bakery products will always be considerably enriched in flavor, texture and aroma. Moreover, in addition to offering better organoleptic characteristics, they will always have a better shelf life.
A recipe with natural yeast
Pancakes with natural yeast
- 300 g of natural non-refreshed yeast (at the maximum leavening)
- 14 g of sugar
- 2 g of sodium bicarbonate
- 2 g of salt
Mix all the ingredients for a few minutes and then let them sit for 5 minutes. Heat an anti-adherent pan and pour the mixture into individual portions of a few centimeters in diameter. Cook over medium heat and then stir the fritters and cook on the other side until golden in color and then serve to taste with jam, cream or icing sugar.