Similar to other fermented foods such as vinegar or fish sauce, yogurt likely came about as a happy accident. The prevailing theory is that when fresh milk was being stored or transported, often in animal skins, wild bacteria transformed it into the thicker, tart substance we now recognize as yogurt. While yogurt’s exact origin remains unclear, we know the food dates back to at least 6000 BCE thanks to mentions of its health properties in Indian Ayurvedic texts. The word “yogurt” may have originated from the Turkish word “yoğurmak,” which means to “thicken or curdle.”
Prior to the mid-20th century, yogurt was made at home in some immigrant communities, but it was a rarity on American supermarket shelves. In 1904, Russian microbiologist Ilya Mechnikov (or Elie Metchnikoff) of the Pasteur Institute in Paris shared a theory that “lactic acid bacteria in the gut could help prolong life by combating toxic bacteria,” writes Janet Fletcher in her book Yogurt (2015). This inspired Isaac Carasso, a Greek entrepreneur living in Spain, to make and sell yogurt. His son, Daniel, eventually took over the business, and when he immigrated to the United States in 1941, he brought his business with him, eventually calling it Dannon. Dannon is now one of the largest yogurt manufacturers in the world.
Today, the variety of yogurt available in American supermarkets is awe-inspiring. Between thickness, fat level, flavor, milk type, and more, there are many factors to consider—and nearly every country in which yogurt is a staple has its own distinct take.
To learn more about this cherished cultured dairy product, we tasted 18 options from nine countries (the widest range we could find in the Boston area) in the most basic style: plain whole milk. The yogurts’ flavors ran the gamut from incredibly acidic to mildly tart, and their textures ranged from thin and pourable to thick and luscious. We interviewed chefs, cookbook authors, and yogurt makers to learn everything we could about this fascinating food.
Yogurt Around the World
In most regions outside of the United States, yogurt is used as an ingredient in savory dishes or added as a condiment to any meal throughout the day.
At Sofreh, a Persian restaurant in Brooklyn, New York, chef/owner and author of Sofreh (2023) Nasim Alikhani said it was initially difficult to get her American customers to see yogurt as anything other than a sweet breakfast component. “At home, we always set the table with a bowl of yogurt,” Alikhani said. After attempting to get guests to dip into a side dish of homemade yogurt, Alikhani eventually began adding generous dollops to dishes, coaxing diners to recognize how yogurt can augment many meals, such as a steaming bowl of fragrant lamb meatballs.
In Bulgarian cuisine, yogurt is used in soups, sauces, and savory drinks. It’s an ingredient in tarator, a cold yogurt-cucumber soup, and snezhanka, a salad of yogurt, cucumbers, walnuts, and dill.
While yogurt is sometimes thought of as a sweet breakfast component, it also shines as a garnish, such as on braised eggplant or as an ingredient in a savory soup like tanabour.
In Armenian cuisine, yogurt is used as a condiment and in dishes such as the yogurt-barley soup tanabour, where it contributes tartness and silkiness.
Yogurt is also a star in Greece, of course. It’s used in the iconic tzatziki and as a garnish on grilled meats and vegetables. At breakfast, it’s often enjoyed drizzled with honey.
In Iceland, skyr is sometimes made with rennet and categorized as cheese. The American brands of skyr we tried were more similar to yogurt, made with only milk and active cultures. Skyr can be eaten with fruit for breakfast or used to make sauces or marinate meat.
In Turkish cuisine, yogurt is the main attraction in çılbır, a dish in which a bed of yogurt is garnished with delicate runny poached eggs and finished with a drizzle of pul biber–spiked melted butter. Yogurt is also mixed with water, salt, and sometimes mint in a beverage called “ayran.”
Indian yogurt (also called “dahi”) “is considered cooling,” said Kaumudi Marathé, author of The Essential Marathi Cookbook (2009) and senior books editor at America’s Test Kitchen. Dahi is essential to raita, the yogurt-vegetable side dish. “We also use yogurt to make marinades for meat, as well as some sauces,” such as kadhi (a yogurt sauce thickened with chickpea flour), said Marathé.
How Yogurt Is Made
No matter where it’s made or enjoyed, all plain yogurt starts with the same ingredients: milk and/or cream and bacterial cultures. Commercial yogurt makers are required to pasteurize the milk to kill bad bacteria. This means heating the milk to specific temperatures for certain amounts of time. The milk is then cooled, since temperatures that are too high can kill the good bacteria necessary to create yogurt. The milk is warmed again to around 115 degrees Fahrenheit, and a culture, or bacteria, is introduced to convert the milk to yogurt, impacting both the flavor and texture.
With homemade yogurt, the starter culture is often a small portion of already-made yogurt (store-bought or homemade). Larger producers use manufactured cultures in powder form. In the United States, for a product to be defined as yogurt by the Food and Drug Administration, the cultures used must include Streptococcus thermophilus and Lactobacillus bulgaricus. Other species of cultures can be added but are secondary in importance.
Ask Paul: What Is the Difference Between Yogurt and Kefir?
Is there really a difference between two different styles of fermented milk? And what about water kefir?
Learn MoreNext, the milk-culture mixture is kept at a warm temperature for anywhere from a few hours to a few days. At The White Moustache in the Red Hook neighborhood of Brooklyn, New York, they even wrap their vats of yogurt in mylar blankets to keep them warm, said Homa Dashtaki, owner of The White Moustache and author of Yogurt & Whey (2023). During this time, the bacteria convert lactose (the sugar naturally present in milk) to lactic acid, making the yogurt tart and thickening it by coagulating some of the proteins.
Some large yogurt producers also add dry milk solids for extra thickness and creaminess. Because these products are technically milk without any other ingredients added, they don’t have to be listed differently on labels, but sometimes they appear as “milk protein concentrate” or “nonfat milk solids.” These are similar powdered substances, but milk protein concentrates are higher in protein and lower in lactose than nonfat milk solids.
At this point, many styles of plain yogurt are packaged and ready to eat, while others are strained to make them thicker.
At home, we always set the table with a bowl of yogurt.
—Nasim Alikhani, owner of Sofreh, a Persian restaurant in Brooklyn, New York, chef/owner and author of Sofreh (2023)
A Look at Texture
In our tasting, we found that whether a yogurt was strained or unstrained was a key differentiator when it came to texture. Greek yogurt and Icelandic skyr are strained before packaging, removing the liquid-y whey (you can learn more about whey, a solution of noncasein dairy proteins in water, in our FAQ below). This makes them much thicker. Traditionally, straining was done with cheesecloth and gravity over a long period of time. Now, larger yogurt producers can spin out the whey using a centrifuge or drain it using a special filter. When yogurt is strained, the milk solids are concentrated and protein levels increase. We tasted a Greek yogurt with 16 grams of protein per serving and an Icelandic yogurt that had 18 grams—the most in our lineup and more than double that of the unstrained varieties.
The other yogurts we tasted were unstrained and therefore more loose and liquid-y. The American whole-milk plain yogurt from Maple Hill, for example, had a very runny, pourable consistency. Bulgarian yogurts were also notably thin.
Depending on whether it is strained, yogurt can be liquidy (left) or thick and luscious (right).
Sometimes yogurt producers add pectin for additional thickening, giving body to the yogurt without any straining. The Armenian-style yogurt we tasted from Karoun had a medium-thick texture, and the Turkish-style yogurt from Merve was thick and velvety. Both listed pectin in their ingredients.
The Flavor Landscape
The yogurts we tasted ranged from mild and milky, like Indian dahi, to notably tangy and sharp, like one Iranian product.
Some manufacturers develop yogurts to be quite tart, choosing cultures that will result in higher acidity levels. In our lineup, the Bulgarian yogurts were the most acidic, with pH levels of less than 4 (the lower the pH, the higher the acidity). Given the high acidity of these yogurts and their low sugar content (the lowest in our lineup), it was no surprise that our tasters found the Bulgarian yogurts to be by far the most tart.
Other varieties, such as Indian, French, and American, tended to be sweeter. One of the Indian yogurts had the most sugar per serving in our lineup, due to its use of nonfat milk solids, which are high in lactose.
Although none of the yogurts we tasted contained added sugar, some had naturally higher sugar contents due to the milk’s lactose. Thicker strained varieties, such as Greek yogurt (right), also had much higher protein content.
Richness was another area where the yogurts varied. We focused on whole-milk yogurts (as opposed to low-fat or nonfat), selecting those from 3 to 5 percent fat where possible. Some products contained cream in addition to milk. The whole-milk Greek yogurt from Fage and French-style yogurt from La Fermière had some of the highest fat contents in our lineup—9 and 15 grams of fat per serving, respectively. Tasters noticed they were especially “decadent” and “rich.”
Which Yogurt Is Right for You?
Supermarkets stock a surprising variety of yogurts these days, but if you have South Asian or Middle Eastern specialty markets in your area, we encourage you to explore the products they carry. Some stores may even make their own exquisite yogurts. We tried one from Sophia’s Greek Pantry in Belmont, Massachusetts, that one taster called a “life-changingly perfect yogurt.”
We encourage you to dive in and try something new. We listed everything we tasted below, alphabetically by country. Sweet or tangy? Creamy or drizzly? The world of yogurt awaits.
- Taste 18 samples plain
- Nutritional information was obtained from the labels and is based on a 170-gram serving
