Greek yoghurt (as sold by us) is obtained by means of final filtration, to remove the residual acidic water.
Method to do it home.
Prepare before the yogurt using the machine normally, following the instructions.
Place a strainer into a bowl. Place the strainer inside a tightly woven cotton cloth.
Pour the yogurt in cotton cloth. It does not matter if you just did, it is okay the next day also.
At this point, wait for the whey drip into the bowl, for a couple of hours or more.
The whey is what gives the flavor a bit sour to the normal yougurt.
In a couple of hours you get the thick yogurt. The more time passes, the more it becomes thick yogurt. After 4-5 hours, becomes like cream cheese.
During the filtering, every so often, it is good to reshoot the yogurt with a spoon, so that the more dense (that it lies in contact with the cotton cloth) not makes a "cap" to the more still in the surface.
By us in Italy yogurt is made with both, Lactobacillicus Bulgaricus and Streptococcus Debrucii. In addition we put probiotic ferments.
The Russian microbiologist Ilya Ilyich Mečnikov isolated Lactobacillus bulgaricus and Streptococcus thermophilus. And recognized that these Lactobacillus were responsible for the process of breaking down lactose into galactose and glucose. These "ferment" act with a mechanism proto simbiotic: streptococcus works first, creating the conditions for the lactobacillus do the work of breaking down lactose.
Although opinions are sketchy at best, today, in contrast to what is touted by advertising, it is believed that these two enzymes play no active role in the human body: in fact, they die as soon as they come into contact with gastric juices human, I can not stand the acidity
By the result of the positive feedback the use of probiotic ferments in the medical field, today some manufacturers have begun to add yogurt to their products. The probiotic ferments, unlike the Lactobacillus bulgaricus and Streptococcus thermophilus, are able to withstand the free acidity of gastric juices, to survive and replicate in the gastrointestinal tract. Since, generally, as bacteria already present in the human body, they are able to restore the bacterial flora to a normal state, when this has been compromised as a result of treatment with antibiotics, by stress or by improper nutrition.
The probiotic ferments exercise also a positive effect in many processes of digestion and prevent intestinal infections and attacks by fungi, strengthen the immune system produce bacteriocins, the so-called "natural antibiotics". The main probiotic ferments added in the fermentation process are the following: Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus lactis, Bifidobacterium bifidum.
The fermented milk obtained from their action deviates slightly from yogurt (traditionally obtained only with the use of Lactobacillus bulgaricus and Streptococcus thermophilus), giving rise, rather, to a Kefir.