The western world calls it Bulgarian yogurt but in its homeland, it is called Bulgarian sour milk. Whatever the name, this wonderful probiotic food has impeccable ancestry. In the twelfth century, it is said that Genghis Khan fed his troops on it - and look what they achieved!
And this type of yogurt was old then - it is believed to have been known for at least 4000 years.
For yogurt to be considered of the Bulgarian variety, it needs to be made with two specific starter bacteria, Lactobacillus delbrueckii subspecies bulgaricus (often simply called Lactobacillus bulgaricus) and Streptococcus salivarius subspecies thermophilus (often shortened to Streptococcus thermophilus). Now most yogurts contain these two as they are such excellent starters but most "ordinary" yogurt has other good bacteria added as well.
Originally it was made from sheep's milk but Bulgarian yogurt can also be made from cow's, goat's or buffalo's milk too.
Popular folklore has that Bulgarian yogurt originated when sheep-herders carrying milk in goatskin bags found it turning into yogurt and discovered that, far from this being a bad thing, the milk kept longer and proved to have a beneficial aspect on the human body.
It appears that some property in buffalo milk allows large numbers of active bacteria to reach the intestinal tract.
Lactobacillus delbrueckii subspecies bulgaricus andStreptococcus salivarius subspecies thermophilus are not normal inhabitants of the specific microflora of your gastro intestinal tract. Because of this, they do have a rough ride through your stomach - only about 15% survive wading through the gastric juices - and only about 1% of them reach the colon so it seems to me that this advantage that buffalo milk has is very beneficial.
The buffalo milk version of yogurt is a brilliant white because the milk is low in carotene as the buffalo convert it to Vitamin A. It contains less water than cow's milk so the milk appears thicker and makes a creamier yogurt. Buffalo milk (and the yogurt made from it) contains more fat, lactose, protein and calcium than cow's milk and also produces a stronger tasting yogurt.
You too can make Bulgarian yogurt if you wish. Whilst the sheep-herders probably had a trick or two up their sleeve about sheep herding I suspect they were not that much brighter than you and me. If they could do it, so can we.
Follow your normal yogurt making method but you must inoculate your milk with L bulgaricus and S thermophilus, either by buying some starter that states it contains only those two bacteria, or using a commercial batch of the real thing. Most yogurts will not contain the right bacteria, although they will, of course, produce perfectly delicous "normal" yogurt. Many have L acidophilus added and this bacteria is not one for authentic Bulgarian yogurt.
I don't know how authentic this Bulgarian Yogurt Culture is but it could be worth trying.
It is believed that the strain of bacteria nowadays called L bulgaricus is not the original strain referred to by Metchnikoff, the Russian born Nobel Prize winner who could be called the father of probiotics.
The strain he refered to could produce 25g/l of lactic acid when grown in milk, but this high level of acidity is not typical of the modern day L bulgaricus but sounds more like a strain of L helveticus.
In the international culture collections there is only one strain identified as "one of the original Metchnikoff strains" and it is was deposited as L jugurti which is nowdays recognised as a strain of L helvitcus.
In Bulgaria, it was the custom for each household to make their own yogurt, but as the process became more industrialised, the Bulgarian people felt that their life-enhancing yogurt was deteriorating in flavour.
To stop this deterioration, a large number of lactic acid bacteria were isolated from yogurts still being made by people in the different country areas of Bulgaria. Seven starters that contained the "magic" of the original Bulgarian yogurt were used to improve the quality of the yogurt being produced by the dairy industry.
The wonderful thing is that some of those original starters such as 5-12, 144-12 and 37-18 are still used for yogurt production today.
One of the reasons behind the flavour and health-enhancing aspects of authentic Bulgarian yogurt is that it was originally produced by the method that has always produced the best of the world's food ie using the best as parent for the next generation.
Whenever someone in a village needed to make yogurt, obviously they needed to first find a starter. Naturally, they would use the tastiest, most desirable yogurt they knew of for that starter. So over the centuries of yogurt making in Bulgaria, their yogurt has been continually selected for the best of qualities. Never was the selection based upon what "filler" could give a manufacturer more dollars for his product or any of the other considerations that go into so much of our food production nowadays.
It is believed that some of the original starters came about through vegetative means when milk was inoculated by the shepherds in the Rodopi mountains of Bulgaria. They softened the roots of plants such as Christ's thorn (Paliurus aculeatus) and Barberry (Berberis vulgaris Lam) and put the resulting juice in the milk to inoculate it.
Through the centuries of symbiotic interaction between these two wonderful Bulgarian starters - one taken from milk and one taken from plants - a unique taste developed. Many people believe that "true" Bulgarian yogurt can only be made through using starter from Bulgaria. Most of the original starters have been patented and are now in world wide production so you probably can make something pretty authentic by choosing your source carefully.
Unfortunately, much of the research on this health giving yogurt and sour milk is written in - you guessed it! -Bulgarian. So until my language skills improve - that's your lot!