Mother yeast, commonly called natural yeast or sourdough, is a mixture of flour and water that has been left to ferment for a few days naturally for a certain period of time, with the addition of sugars: this process allows the microorganisms present in the flour, in the water and in the air to reproduce and ferment.
These microorganisms, present in the mixture, are saccharomycetes (including the various strains of Candida Saccharomyces e) and heterofermentative lactic bacteria (parts of the Lactobacillus families such as brevis, casei, acidophilus, plantarum etc.). It is also the bacteria and yeasts of the atmosphere that transform the sugars of the compound into acids.
Furthermore, unlike brewer's yeast (consisting simply of a single bacterium, part of the Saccharomyces strain), mother yeast contains many other bacteria, part of the Lactobacillus genus, and responsible for the transformation process of sugars into lactic acid.
The mother yeast, due to its composition, can be subject to two types of fermentation, the alcoholic type and the lactic type, which gives the bread or pizza a particular taste, and makes it more digestible.
This sourdough has an ancient history behind it. It is thought that fermentation, which we now use daily, was discovered in 2000 BC. C, by pure chance. It is speculated that this great discovery was made in Egypt, when a portion of the dough for unleavened bread was left in the sun, starting to grow and grow, increasing in volume. Once cooked, the bread was much softer and more pleasant than the usual unleavened bread.
The sourdough, however, is not found on the market. It is in fact necessary to produce it yourself, and it is precisely for this reason that different schools of thought have been formed on what is the best way to prepare it and consequently many recipes.
All the recipes for making mother yeast start from a base of water and flour. These recipes can then be enriched with a sugar, honey, yogurt or even a slice of apple.
Here are the ingredients needed for the preparation in the mother yeast:
Flour: The best flour for the preparation of sourdough is a high-yield flour with a good percentage of gluten.
Water: Choose a water that is obviously drinkable, and not too rich in mineral salts, as these could hinder the fermentation process of your dough. You can also experiment with sparkling water! Carbon dioxide is in fact an essential element in the transformation of sourdough.
Additional ingredients: It is not necessary, but to speed up the work of microorganisms during the preparation of a natural yeast it is possible to add fruit to sweeten it, peels or even yogurt. These products also accelerate fermentation.
Refreshments are necessary for the preparation of natural yeast.
Refreshments are fundamental and necessary steps for the preservation of your yeast, keeping it alive and healthy for as long as possible. They usually precede the preparation of the final dough, with the aim of enhancing the fermentation capacity of our yeast, as well as lowering its degree of acidity.
Remember that yeast behaves exactly like a living organism, and it is therefore necessary to feed it at least once a week, through refreshments.
Normally the innermost part of the yeast is taken, a part is extracted, and flour and water are added. But there are distinctions.
For carry-over refreshments, designed to keep the yeast alive, 50% of water is used together with the added flour, while for the yeasts in preparation for the dough the same weight of flour is added with an addition of 10%, and 50% of water on the weight of the yeast.
Example:
Each 1 kg of yeast: + 1100 g flour + 500 g water.
The fermentation phase ends when the yeast has tripled its volume. Refreshments are usually repeated three times before the end of the leavening process.
A fundamental tip is to check the volume reached by your yeast using a "spy". In fact, this is how a small part of yeast is called, inserted in a graduated cylindrical glass to act as a guide and help to follow the leavening.
As for the preservation of your yeast, place your sourdough in a glass container in the fridge. If refreshed at least once a week and placed in a fridge at about 4 °, I will be able to survive for about a week. To keep the product longer it will be necessary to pulverize it.
Ingredients: 100g of ripe fruit - 200g of flour - 50g of water
Start by mixing the ingredients evenly, and then place your dough in a container full of water, at a temperature from 20 ° to 24 ° C. The quantity of water must be at least four times higher than the weight of the pasta, which must in fact sink completely. Let everything rise for 48 hours, at a temperature of 26 ° / 28 ° C.
Once 48 hours have passed, also thanks to the carbon dioxide, the dough will begin to float. If this does not happen, try to repeat the operation, mixing with the same weight of flour and 40% of water.
When your yeast has finally reached maturity, you can move on to the next step, and proceed with the refreshments.
Ingredients: 200g of flour - 90g of water - 1 tablespoon of oil - 1 tablespoon of honey
Start by mixing all the ingredients, creating a loaf, and then put the mixture in a glass container (with lid). This should be left to rest at a temperature of 25 ° ~ for 48 hours.
Then take 100g from your dough, and add 100g of flour and 45g of water, making sure it is at room temperature.
Mix well, then close the container and let your product rest for another 48 hours.
Refresh the yeast again in the same way, and continue this operation for at least one / two weeks, taking care to refresh the product every day, in order to make it capable of doubling its volume in less than four hours.
Ingredients: 200g of flour - 100g of pureed fruit - 100g of water
The use of mineral water is recommended.
Mix the ingredients evenly, and place them in a container containing water at a temperature of about 20 °. The water must be four times the weight of your pasta and cover it completely. Leave the dough to rise at a temperature of 26 ° / 28 ° for about 48 hours, making sure it is covered.
The dough will begin to float, if developed optimally.
Then mix with an equal weight of yeast and flour, cooling until the yeast has reached maturity (usually takes 20/25 days).
The mother yeast, following the preparation, can present itself in different ways.
If Ripe, it will have an almost acidic taste and an alcoholic scent, it will be characterized by a soft white body and elongated alveolation, with a pH of 4-4.10.
Past of leavening will have an acid and bitter taste, acrid perfume. The appearance will be grayish in color, with round alveoli and a ph of 3-3.8.
When Too weak it will have a sour and sweetish taste, it will be white in color and scarcely alveolate. The ph will be around 5-5.5, and it will smell like flour.
Finally, soured yeast has a very strong taste, smell similar to that of cheese, mainly due to the butyric acid, a grayish color and the dough will be moist and sticky. The ph will be far too low.
Here are the perfect methods for solving these various issues
Slice your yeast, put it to soak at a temperature of 20-22 ° C, with about 2 gr. of sugar for every liter of water. Then leave the slices to soak for 10-15 minutes, and squeeze the yeast and then move on to the refreshments.
Here are the dosages:
yeast 200g
flour 400g
water 200g
At the end of the refreshments, the yeast must mature in 4 hours at 28 ° C.
Start by refreshing the yeast by following these dosages:
mother yeast 250g
flour "00" 200g
water 100g
Start kneading, until you get a homogeneous and dry mass, and let it rise as you usually would. You can then move on to the refreshments, dosing the flour carefully to the consistency of your yeast, so that it can ferment in 4 hours.
The washing procedure is the same as the previous one, but it will be necessary to rebuild the yeast. Here is the necessary, with exemplary dosages.
mother yeast 250g
flour "00" 500g
water 250g
egg yolk 20g
3g sugar
Knead until the product is smooth and dry, and let it rise up to three times its original volume.
Here too, start with the refreshments, dosing the flour and water in order to obtain a yeast with the right strength, capable of fermenting in 4 hours. Please note that egg yolk and sugar will not be needed in subsequent refreshments.
The day before using your yeast you will have to refresh it, and wait for it to become active before using it.
At this point you just have to choose a recipe and start experimenting.
