Starting with raw milk from animals like cows and goats, you make yogurt by standardizing milk: reduce fat content and increase total solids before pasteurizing to remove harmful bacteria. After pasteurization, the milk undergoes homogenization to make it smoother and more consistent. The milk then receives yogurt cultures, and the product undergoes a fermentation process. Finally, you can cool the yogurt and prepare it for packing.
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The “culture” that turns milk into yogurt
The key ingredient for producing yogurt is the starter culture that goes into the milk. These cultures or bacteria ferment and produce lactic acid, which acts on the milk protein to give yogurt its texture and taste. Adding the necessary bacteria in a controlled manner is important since the level of acidity during the fermentation process affects the final product. The incubation process takes place inside a sealed hygienic stainless-steel cylindrical vessel equipped with devices that measure and control the temperature, pressure, and pH level. The acid level of the product is monitored until it reaches a pH level of about 4.4 to 4.5. Then, the yogurt is cooled to end the fermentation process.
How do you like your yogurts served? The different yogurt making equipment that makes the difference
Yogurts come in different types due to differences in processing. The common processes start from the standardization, pasteurization, homogenization, and fermentation of milk. After that, you can opt for different techniques and materials depending on the type of yogurt you want.
Set, stirred, liquid…
Set yogurt is the firmest type with a jelly-like texture. Its fermentation occurs directly in the selling container, which makes it firm. Stirred, one of the most common yogurts in the market, has milk fermentation in a single container. You need to cool it to stop the fermentation process and then include fruits and flavoring. Finally, you put in individual containers, making it less firm than set yogurts. Liquid yogurt, the drinkable type, has a similar process to stirred yogurts, but with more agitation to break up the coagulum. One way to do that is to let the yogurt undergo a homogenization process after initial cooling from fermentation.
Frozen yogurt started out as a mixture of milk, cream, sugar, and other ingredients based on a particular recipe. The liquid ingredients are mixed into a vat and heated. After mixing the ingredients, pasteurizing, homogenizing and stirring the yogurt culture in the mixture, you must cool it down slowly. Then, store it in aging tanks inside coolers for about 4 hours. Add other flavorings and pump the mixture to the freezer, where it will agitate until it freezes and achieves the desired overrun. Next, pack the mixture and place it in freezers to continue the freezing process rapidly to form tiny and smooth ice crystals, giving the frozen yogurt its ice cream texture.
...and Greek yogurt
Greek or strained yogurt undergoes a similar process to stirred yogurts. The difference is that you must remove the liquid whey after stirring by heating and straining through filtration or centrifuge, which results in a thick and concentrated product. As a result, the product has a much higher protein content. The name “Greek yogurt” got popular in the United Kingdom in the 1980s, when strained yogurt was imported to the country by a Greek company. That was the moment when “Greek yogurt” became the same as strained yogurt in English.
Available in a wide variety of flavors and fruits
Yogurts with different flavors and aromas have become quite popular. The most common variety is fruit-flavored yogurts, to which you add flavorings such as puree or whole fruits in syrup before filling the containers with yogurts. For stirred yogurts, you add the fruit after cooling the yogurt. For non-fruit flavors, you can add these to the yogurts before dispensing them into containers for packaging.
Filling it up and sealed for freshness
Yogurts, like most dairy products, require aseptic filling and sealing. In this case, you sterilize the equipment, containers, and packaging material using steam, heat, and other treatments to avoid contamination. Use precise filling machines to fill the containers to prevent drip or spillage. After filling the containers, they are sealed with hygienic lids before being sent for packing. Aside from precise filling and sealing of the containers, conveying these products after filling requires stable handling to minimize the breaking down of physical properties, especially for set yogurts.