Biotechnology is the use of living systems and organisms to develop or make products, or "any technological application that uses biological systems, living organisms or derivatives thereof, to make or modify products or processes for specific use
HOW TO CONTROL THE FERMENTATION.
Yogurt making is a biotechnological process. In order to make yogurt, you have to mix yogurt bacteria with warm milk. There are three main factors which are important here
Dairy milk from cow`s, sheep`s or buffalo`s is the best food for the bacterial fermentation. The product’s acidification happens when lactose, milk’s sugar, is separated into two simpler components, glucose and galactose, with the production of lactic acid. This quality makes the product more suitable for anyone who suffers from a milk intolerance, which is caused by the lack of an enzyme called lactase. The fermenting process is triggered by lactic cultures belonging to two main bacterial groups: Lactobacillus bulgaricus and Streptococcus thermophilus
Must be between 40 and 45 degrees Celcius(23-29 degrees Celcius for Kefir) This is the ideal temperature which let the bacteria to multiply and flourish.
The time for fermentation depends on the factors above.
Check our YOGURT APP for an easy start
Yogurt at Home
Incubate for the time stated below
Once the first batch of yogurt is ready, place it in the fridge. In this way, you will have activated yogurt for the next few weeks. Just take a spoon or two and add warm milk. Mix well and incubate at 40°C - 45°C (104°F -113°F) for 3-6 hours and voilà – the new batch of yogurt is ready. You also can freeze some in a sealed container,so you can keep activated yoghurt for months.
One step left - take out the yogurt from the fridge after 3 - 6 hours and Bon Appétit!
How to Make Kefir at Home
Now you can prepare the next batch of Kefir using the 3 tablespoons of Kefir you took from the previous step. Add a litre of milk stir well and leave it at room temperature for 24 hours.
Please note that all further batches from this original sachet only need 24 hours to culture. For each fresh batch, remove 3 tablespoons as above and repeat the process. After 4 to 5 weeks, when the Kefir is beginning to get thin and watery, use a new packet of Kefir and restart the cycle. Prepared Kefir should be stored in the refrigerator and consumed within 48 hours.
Choose a safe spot. An ideal culturing place should be relatively warm but not excessively so. Temperatures between 20° and 29°C (70°F - 85°F)are ideal. The best fermenting spot for kefir is out of direct sunlight. Indirect light or darkness is neither favourable nor problematic. Be sure the kefir is not fermenting near any other cultured foods such as kombucha, yogurt, sourdough, sauerkraut, etc. Do not culture your kefir near a garbage can. Cross-contamination of stray yeasts and bacteria can be problematic for the kefir and any other fermented foods you are working with.
Signs the Kefir is Done Culturing
Cow or Goat Milk: The culturing process is complete when the milk thickens to the consistency of commercial cultured buttermilk. It will be a pourable liquid and not an “eat with a spoon” level of thickness, although if it is fermenting longer will become thick. If you prefer it pourable please shake it well before to put it in the fridge. The milk will also take on a distinctive sour fragrance.
Coconut Milk: The coconut milk takes on a distinctive sour, less sweet fragrance. Cultured coconut milk does not thicken reliably like dairy milk.
Coconut Water or Juice. The coconut water or fruit juice becomes cloudy and less sweet.
Yogurt & Kefir with Alternative Milks
Yogurt is a dairy product - The lactobacteria multiply and flourish in dairy milk environment because dairy milk contents all elements they need, also the chemical structure of the dairy milk determines the biotechnical processes and conversion of the milk in yogurt. Dairy milk contents milk sugar ''Lactose'' also a specific protein called ‘‘Casein’’ These two determine the texture of the end product.
On the other hand, most of the milk alternatives are actually plant juices as coconut milk, or water-based extract of particular source like almonds, soybeans, rice etc.
Although for example, soy milk is a very close to cow`s milk as they both contain a similar amount of protein and sugars - the sugar is a different type and is called ''Sucrose'' and basically is ''table sugar''. These small differences in quantity and type of sugars as well vegetable origin reflect significantly on the end product and approaches when you have to make yogurt from alternatives to dairy milk. The end product might not look like dairy yogurt. However, the bacteria will be present inside, as well healthy benefits.
Before to start making yogurt with dairy milk alternatives, please consider.
1. Origin of the plant milk which you will use. Please make sure that there are no any preservatives inside or they will kill the bacteria in the starter (please remember that the kefir and yogurt starters contain live bacteria). The best plant milk is that you can make on your own at home. Most of the ''shop ones'' contain some preservatives in order to extend the shelf live.
2. Please do not boil the plant milk, this will ultimately change their structure, but please pour boiling water over containers and equipment which you will use, to remove other bacteria which can get in competition with the yogurt or kefir ones for food. Please do not use cold plant milk - the temperature of the milk should be lukewarm.
3. Please add a small amount of sugar in order to provide bacteria with food. Please do not forget that bacteria eat sugars - the milk is just a medium which provides them with food. Please also do not add too much sugar, because after some point the sugar can act as a preservative - so the balance here is essential - 1 teaspoon per litre should be OK.
4. Activation(first batch made with freeze-dried culture) and alternative milk should be very carefully considered. The bacteria in the freeze-dried starter are in a state of hibernation, so they are fragile at this stage and sensitive to the medium. A small difference in the quality of milk, temperature and they will die. The alternative kinds of milk are not the perfect medium for lactobacteria so the result will be unpredictable. Please activate freeze dried starter with traditional dairy milk and then use 2-3 spoons to re-culture batch with alternative milk.
5. Yogurt/Kefir made with alternative milk will not be able to re-culture successfully with small exceptions as that made with soy milk.
6. Once your yogurt/kefir has completed setting up is possible to be divided into curds and whey. This is normal for yogurt/kefir made with alternative milk. Please place it in the refrigerator to thicken up and after few hours remove the liquid using cheesecloth.
However, some people with severe lactose intolerance might be sensitive even to those 2-3 spoons of yogurt/kefir made with dairy milk which is used as a starter for a new batch of alternative milk even though they are greatly diluted in the alternative milk, and the lactose has been broken down to simple sugars.