Lassi is prepared by blending yogurt, water, and spices. In Punjab, the yogurt is traditionally made from water buffalo milk. However, variations of lassi can be prepared in different ways. Cumin and cardamom are the most common spices added to lassi.

If we take a look at these two drinks, they both look similar, but they differ a lot in their taste and flavour. While buttermilk is prepared with spices, on the other hand, lassi is prepared with milk, cream, sugar and sweet taste of fruits. In the process of making buttermilk, lactose is converted into lactic acid.

In India, some Hindus have resorted to using the term "lassi" as an insult directed at Sikhs, targeting their dietary preferences and cultural heritage. Witness the response when a Hindu attempts this derogatory term with a Sikh.

The lassi is sometimes referred to as the original milkshake or the original smoothie, although it predates the blender by at least 3,000 years, and was, in the days before Vitamix, prepared by vigorously stirring the yogurt, water and any additional fruit or spices in a simple clay pot with a stick or long spoon.