A Bit of History:
Traditionally, yogurt has been made as a simple “set” yogurt, which means that it was, heated, cooled to fermentation temperature, specific culture added, fermented, and then cooled to be left as a complete curd with no breaking of the yogurt mass before it was ready to eat.
This is also commonly known as “Balkan” or “Bulgarian style” yogurt (our Y1 culture). These yogurts are covered in the initial yogurt pages I did a while back. These yogurts are always fermented in their final consumer containers.
Then came Dannon Yogurt, originally produced in Spain as Danone, moving to France in 1929 to perfect their large scale production, and then to the Bronx in NY in 1942 where they changed the name to Dannon. However, they had one major problem; most Americans had never tasted yogurt and so their sales were confined to the New York City area. The traditional high acid flavor was not appreciated in America as it had been throughout Europe.
Then, in 1947, Dannon introduced yogurt with strawberry fruit on the bottom. This change truly appealed to the American taste with the sweetness of the fruit complementing the tart taste of the yogurt. Blueberry and raspberry fruit, as well as orange and lemon flavors, soon followed and became the favorite yogurt of America. The changes also included adding more sweeteners to these yogurts, which increased with time.
The next big change in yogurt was the switch to a low fat yogurt due to the health awareness of fat in diets that began to creep into the American culture during the 1950’s (“Fat is Bad”??).
Eventually the “stirred yogurt” (also known as “Swiss” style yogurt) evolved, which meant that the milk was heated, cooled to fermentation temperature, specific culture added, fermented in large vats, and then cooled to room temperature.
.... BUT for these, the yogurt was lightly stirred as fruit and sweeteners were blended into the yogurt body, and then dispensed into individual servings and chilled to storage temperature. Within 2 days this stirred yogurt begins to form back into a creamy consistency with the fruit and other flavors mixed evenly throughout. The texture is quite different from the “set” yogurt.
The newest entry to yogurt is the “drinkable” yogurt style. This is a style that is made similar to the stirred yogurt but the final acidity is slightly higher (for a brighter flavor) and the breaking of the coagulum is much more thorough with little to no recovery of firmness in the final cooling.
The “drinkables” are a real rising star in popularity to match our “on the go” lifestyle. Kids and young adults especially, just love these.
However, I must say that over the past several months, I have tested a lot of serious adult palettes with what I have been making and found that these were their new favorite yogurts.
I managed to get a family of friends spanning 3 generations to try my experiments and there was a unanimous "Yes!" from them.
The picture above indicates that there was also a cross species testing going on as well, with a pretty good approval rating.
Yogurt - the Basics:
Essentially all yogurt starts with milk heated to 180F or higher and held for several (15-30) minutes before cooling to the target temperature for bacteria culture addition (108-112F) and then held at this temp for the culture to ferment the lactose in the milk and add the characteristic flavor of yogurt. The thick texture of yogurt is primarily due to the high heat destabilizing certain whey proteins and causing them to link together forming the yogurt body.
Without this step in heating and cooling, you really do not have a true yogurt. The final result would be a much thinner fermented milk. Not that this is bad, but it is not yogurt. Many folks want to preserve the enzymes and other goodies of raw milk and for them I encourage exploring the more complex cultures of kefir.
A good yogurt culture is primarily made up of 2 high temperature Thermophilic cultures:
- Streptococcus.thermophilus – The initial acid producer
- Lactobacillus.bulgaricus – capable of producing a higher acid level
These cultures tend to work in tandem and are actually symbiotic, meaning they do better together than either does separately. Each provides something for the other, teamwork, you know!
Not all cultures are the same because the balance of the two major culture groups above may be blended in different ratios producing different levels of acidity, textures, and flavors. There also may be many different strains of each type. For example:
- our tangiest yogurt is the Y1 ‘Bulgarian’ yogurt with the thermophilus to bulgaricus ratio at 1:1 with equal parts of each. This one is most like the continental yogurts of eastern Europe.
- our sweetest yogurt is the Y5 ‘Sweet’ yogurt and the balance is 4:1. The bulgaricus is only 20% of the blend, so it has a lower amount of acid.
This is the one I will be using for this session. This one also includes two probiotic culture additions, meaning that they have the potential of residing in the digestive tract and providing benefits for digestion.
- and in between, we have the Y3 which will give you a good balance between the other two.
For the trials I will be working with here I have chosen Ricki’s Y5 or ‘sweet’ yogurt pack.
Some Notes on Making Yogurt in Different Styles:
For the set yogurt I have already done an extensive page previously found in our recipe section.
For making the stirred yogurt or the drinking yogurt we need to make some changes to the process for a less firm texture.
- The use of different strains and balances in your yogurt culture will change the texture of the final product.
- Less initial heating of the milk (170-185F) will be another major control point, as well as little to no hold time in at that temperature before cooling. Lower temp and time will result in less changes in the whey proteins and thus less linking of these for a thinner yogurt.
- Stirring of the yogurt part way through the final cooling stage (at 65-70F) will break up the firm yogurt texture into a much looser mass. The fruit and other additions can be added at this point.
- Finally, the yogurt should be cooled to its final temperature of 36-39F.