The mother of all pastries - Part 2
Friends of Erre4m good morning and welcome to this new post. Today we will continue to talk about NATURAL LEaven.
The ways to produce a sourdough starter at an artisan/household level are very variable and subject to personal habits, working methods, traditions, etc. These methods are all very valid from a practical point of view even if, as mentioned in the previous post, most of the times the leavener doesn't think at all about what microbiologically happens inside the sourdough but works with the idea of a handed down tradition or because they told me to do it this way.
Every method, from the creation of a mother, to the maintenance, to the refreshment, implies the development of a different microflora according to the conditions that are created; this microflora is the one and only responsible for the sensory characteristics of the finished products, i.e. a more or less sweet mother will lead to a product with such characteristics while an excess of acidity will also be found in the finished product!
A simple example of the development of different microflora within the sourdough starter, which is created according to the different conditions of aerobiosis (presence of oxygen) and anaerobiosis (absence of oxygen), is represented by the system in which the natural yeast is left to ferment.
One system is to wrap the previously kneaded yeast in cotton cloth and then tie it up; the second is to wrap the yeast after kneading with cellophane that is impermeable to water vapour and oxygen; the third is to leave it free in a tub and cover it with cellophane for storage; the fourth is to "drown" it in water, again covered with cellophane.
In the first case, in the layers immediately underneath the yeast surface, an environment with oxygen will be created and this will lead to the development of microorganisms living in the presence of oxygen, while in the core there will be an absence of oxygen with the consequent development of specific microflora; in the second and fourth cases, anaerobiosis will be immediately created with the growth of narrow specific anaerobic microorganisms; while in the third case a truly heterogeneous microflora can be created.
The choice is therefore only up to the operator as long as he is aware that he is above all working with micro-organisms, creating every day a culture on which not only the whole process depends but also the sensorial characteristics of the finished products.
Aware that there is a very wide range of working methods, I will explain in this description a method that can be a valid support for those who approach it for the first time or for those who simply want to improve the microbiological and rheological characteristics of the mother
The preparation of sourdough is simple but at the same time long and delicate. Simple because theoretically it is enough to mix water and flour and leave the mixture in the air to create a good starting point for the realization of the sourdough; long and delicate because it takes, in this case, more than a month to have good results.
The creation of the microbial culture is very slow and in some cases difficult, therefore it is necessary to operate with extreme patience and caution; once the specific microflora has been created, it will have to be maintained with daily refreshments or every other day in order not to let it die. The operation of daily refreshment, that is mixing the mother with flour and water, allows the microbial culture to:
- take advantage of a new supply of nutrients provided by the flour and hydration of the water;
- eliminate much of the metabolic waste;
- renew the culture of microorganisms;
- continue the fermentation in place;
- stimulate the development and growth of lactic acid bacteria and yeasts present.
To reduce the time for the maturation of the natural yeast and to accelerate the acidification of the dough, you can use, as mentioned in the previous post, some starters or substances that introduce both live microorganisms and products of their metabolism. Generally we use yoghurt for the natural presence of lactic acid bacteria, or ripe fruit (blended peaches, tomato puree, grape juice). In this second case, however, in addition to lactic acid bacteria there is a risk of vinegar bacteria and other contaminants that are not always welcome.
For those who simply want to use water and flour (which must have a W of 350-380) must leave the dough in a container covered with a cotton cloth at 30-35 °C for 48 hours, that is until it has tripled its volume and acquired a certain acidity. After 48 hours, the sour dough is wrapped in cloth, tied up and stored for about a month at 20 °C, refreshed daily and washed if necessary.
Below is an explanation of a simple system for making sourdough
Knead 200 g of flour with the characteristics indicated above together with 250 g of low-fat yoghurt 0.1%mg. Once the dough is formed, put it to rise at 26-28 °C in a container covered with cellophane so that no crusts form on the surface for about 48 hours. When the dough has reached one and a half times its initial volume, mix the same amount of yeast and flour (200 g + 200 g) with 88 g of water at 24°C (be careful not to increase the amount of water because it would encourage an excessive development of acetic acid which is harmful if it is not in the right proportion with lactic acid). Proceed with the dough which should be smooth and homogeneous, give it an elongated cylinder shape, put it inside a well cleaned and not bleached cloth, rewind it inside the cotton cloth, tie it with a rope not too tightly like a salami in order to allow the fermentation. The bound yeast should remain at room temperature, possibly at 18-21°C for 24 hours.
The following day remove the yeast from the cloth, cut the two ends with a serrated bread knife and remove the crust that has formed on the outside, keeping only the heart of the mother yeast (200g). Cut it into 1 cm slices, put it in the planetary mixer together with the 88g of water at 24°C and turn at low speed until it is completely melted. At this point add the 200g of flour, create a smooth and homogeneous dough and proceed again with the binding and resting. This operation should be repeated for 15-20 days so that the strength and pH of the yeast are stabilized.
After the 15-20 days necessary for the creation of the natural yeast it is necessary to proceed with the ordinary maintenance and conservation operations, that is, placing the yeast wrapped and tied in the refrigerator for a time that can vary from 24 to 72 hours, always maintaining the recipe weights used for the formation of the sourdough starter.
The wild microflora generated inside the yeast will produce a mature mother yeast with suitable characteristics of slightly acid taste, white colour tending to straw yellow, alcoholic smell, slightly elongated alveolation and PH 4-4,5. Sometimes, however, the variables that condition the development of the sourdough can tend towards a yeast that is too strong or a yeast that is too weak...let's explain the concept:
- if we are faced with a yeast that is too strong, that is, with a bitter taste, a pungent acid smell, a greyish colour, round alveoli and a PH of 3-4, its acidity must be lowered by proceeding as follows: cut the yeast into slices and put it in 1 litre of water at 20-22°c with 2 g of sugar for 10-15 minutes. After washing (called "bagnetto"), squeeze it to remove the acid substances and refresh it with the following dosage: 200g yeast, 400g flour, 180g water. The increase in the amount of flour is intended to lower the acidity of the yeast, in subsequent refreshing operations you must dose the flour to get a yeast at the right consistency and maturity that is fermented in 4 hours at 28 ° C temperature;
- if the yeast is too weak, that is, it has a sweetish taste, a floury odor, a white color, poor alveolation and a pH of 5-5.5, we should sour it in this way: 250g of yeast, 200g of flour, 90g of water, then proceed with the normal operations of refreshment and maintenance.
In conclusion, the natural yeast must be brought to the right strength to be used in the preparation of large leavened items such as pandoro, panettone, colomba or bread dough.
This last preparation foresees 2-3 close refreshments, that is to say that the sourdough is "scraped off" as usual and refreshed normally, only that instead of binding it it will have to be rounded into a ball, it will be cross-cut on the surface with a sharp blade, put into a bowl completely wrapped in the usual cotton cloth and left to rise for 3-4 hours at 27-28°C, the time necessary for the yeast to double its volume and therefore gain strength.
That's all folks...all that's left to do is to wish you all good work and, given the time of year, HAPPY FEAST!
The Blog is edited by Enrico Gumirato, pastry chef and trainer.