This is the 12435th most frequent Russian word.
кефир
Kefir: A fermented milk drink made with kefir grains, similar to yogurt.
In this sentence, 'кефир' is used to refer to the beverage commonly consumed in daily life.
На завтрак я обычно пью кефир.
For breakfast, I usually drink kefir.
Here, 'кефир' indicates a specific flavored variant of the traditional drink.
Вы попробовали новый кефир с клубничным вкусом?
Have you tried the new kefir with strawberry flavor?
In this instance, 'кефир' is used in a general sense, emphasizing its health benefits and characteristics.