What Is the Difference between Yogurt and Kefir?
Many people assume that because yogurt and milk kefir are both cultured dairy products, there isn’t much difference between the two. This is not true. There are many differences between yogurt and milk kefir, including how each is made, the types of bacteria present in each, and the flavor and consistency.
There are two types of yogurt starter: mesophilic and thermophilic. Mesophilic means that the yogurt starter is cultured at room temperature.
Thermophilic means the yogurt starter is heat-loving, and cultures at around 110ºF, in a yogurt maker or similar appliance.
Milk Kefir is a mesophilic culture, which means it cultures at room temperature.
There is also a difference in how each starter is propagated. Reusable yogurt starters, once activated, are re-cultured by mixing a bit of a previous yogurt batch into fresh milk. Once the new batch is complete it becomes the starter for the next batch, and so on. Yogurt cultures generally require reculturing once each week.
Direct-set, or single-use, yogurt starters come in powdered form, and are usually thermophilic. Each new batch of yogurt requires a new packet of starter. While this type of yogurt may be re-cultured a few times, at some point a new packet of powdered starter will be required.
Milk Kefir, on the other hand, is cultured using milk kefir grains. The "grains" are actually a gelatinous mass harboring a generous variety of bacteria and yeast from which one can make continual batches of kefir. Milk kefir grains should be transferred to a fresh batch of milk about every 24 hours.
Milk kefir can also be made from a powdered kefir starter, similar to the direct-set yogurt culture. Powdered Kefir Starter Culture may be re-cultured a few times using kefir from the previous batch, but eventually, new powdered starter will be required.
Types of Bacteria Present
Yogurt and milk kefir contain different types of bacteria, each of which performs different tasks.
The beneficial bacteria found in yogurt help keep the digestive tract clean and provide food for the friendly bacteria found in a healthy gut. They pass through the digestive tract and are called transient bacteria. A chart listing the bacteria strains found in each of our yogurt starters may be found here.
The bacteria in milk kefir, on the other hand, can actually colonize the intestinal tract. Kefir also contains a lot larger range of bacteria, as well as yeasts. For more information on the bacteria generally known to comprise milk kefir grains, click here.
Flavor and Consistency
Yogurt generally has a flavor familiar to most people. Different varieties of yogurt starter produce yogurt that varies from mild to tangy. The consistency of yogurt varies from a thin, pourable yogurt, such as Piima, to a fairly thick, creamy yogurt such as Bulgarian.
Milk Kefir is also tart, but it can have a touch of yeast flavor, due to the beneficial yeasts present in the culture. Milk kefir's flavor is more sour, and has been described as a cross between cultured buttermilk and yogurt.
Most varieties of yogurt are also thicker than kefir, given the same length of fermentation time. While yogurt is almost always eaten with a spoon, milk kefir is usually consumed as a cultured dairy drink.
Both yogurt and milk kefir may be made thicker by draining whey from the finished product.
In addition to these different cheese products, both yogurt and milk kefir are quite versatile, and can be used in many recipes, from dips to baked goods.
Yogurt is a good source of probiotic bacteria, requiring weekly maintenance, depending on the culture chosen. It is generally a spoonable consistency and may be mild or tart in flavor. Yogurt may be used in a variety of recipes.
Milk kefir is a great source of probiotic bacteria and yeast, and requires daily maintenance, if using milk kefir grains. It is generally more sour in flavor and of a pourable consistency. Milk kefir may also be used in many, many recipes.
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