How to Make Yogurt at Home

Aside from convenience, I see no good reason why we should be content with the commercially processed yogurt. Most of the brands come with additives and fillers that are not so great for us, added mostly to ensure that the products have the best shelf life possible, inevitably compromising on quality and taste. So why not make yogurt ourselves! It’s really no big deal once we get the hang of it. After all, didn’t our ancestors figure it all out like 12 millennia ago when they domesticated sheep, goats, and cows?

A Bit of Yogurt History

Yogurt is native to the Middle East, Central Asia, India, and Eastern Europe, where it has been made throughout history to give milk some ‘shelf life’, and to extend that shelf life even longer, it was drained or dried. Ancient Greco-Roman culture, however, deemed yogurt as the food of barbarous nations, according to the first century AD Roman naturalist Pliny. Unlike cheese, yogurt remained unfamiliar to the western world until the beginning of the twentieth century. It was then used mainly for medicinal purposes. Even the name itself, yogurt, was not introduced to the English language until the seventeenth century via Ottoman Turkish yaghurt, which stems from the root ‘yog’ (thicken).

In its native regions; however, yogurt-making was perfected, judging from the different yogurt recipes we find in medieval Arabic cookbooks. In them, we also find non-dairy yogurt recipes, which use milk of coconut and almond, and non-dairy starters, such as wild cardoon. In the United States, the popularity of yogurt picked up around the middle of the twentieth century, and today, it is a familiar item in the dairy isles, touted as a tremendously wholesome food, a calcium powerhouse with good-quality protein, vitamins, minerals, you name it.

Understanding the Fermentation Process

With food that good, it is truly worth your while to make it yourself. With just milk and an active starter, you can easily make a healthier and cheaper yogurt. But first, some essential observations on the fermentation process which make yogurt possible.

To initiate fermentation, we need to introduce to milk lactic acid-producing bacteria. This would usually be a small amount of previously made yogurt. These bacteria will feed on sugar in the milk, known as lactose, and break it down to lactic acid, which results in souring the milk and curdling and coagulating its proteins.

In order to activate the bacteria, we need to introduce it at the temperatures it likes best. The maximum range of temperature is 104–113°F/40–45°C. The bacteria will grow fast, and your milk will coagulate within three hours or so. Alternatively, at about 86°F/30°C the bacteria will work so slow that it will need about 18 hours to set, resulting in a smooth creamy texture, with no whey-separation, and noticeably sour taste.

Also, we need to let the milk simmer for about 30 minutes (more or less, depending on amount of milk used). This will give it a lovely cooked-flavor and concentrate the proteins, resulting in a firmer texture. Of course, your choice of milk will affect the flavor and texture as well, whether it is full-fat or low-fat (no fat-free please! Recent research has shown that milk-fat helps body absorb calcium better), or whether it is milk of cows or goats, the latter being a bit lighter but has a distinctive flavor, which is not to everybody’s liking. If you are lucky enough to have access to sheep or buffalo milk, your yogurt will be deliriously rich with an impressively thick layer of cream on the top. When using low-fat milk, you might want to add to the milk a small amount of powdered milk, which will result in thicker consistency. My favorite is instant Nido by Nestle.

So, after heating the milk, we let it cool down to the above mentioned ranges of temperature. Meanwhile bring your starter-yogurt to room temperature. When you make yogurt for the first time, make sure the container of the yogurt you buy mentions it has live and active cultures. After that you can use some of your own yogurt as a starter. When the milk is ready, take some of it and mix it with the starter, and then gently stir it back into the milk.

Now you are ready for the fermentation stage: cover the milk container, and put it in a warm and draft-free corner. To maintain milk heat, cover it with several layers of a blanket. Keep in mind that the longer you keep the milk fermenting the tartier it gets. To make sure yogurt is done fermenting, slightly tilt the container to see the surface looking set. It is necessary to refrigerate it for several hours to help the yogurt completely cool down and firm up.

Author: Nawal Nasrallah
When you make yogurt for the first time, I suggest you start experimenting with small batches. This recipe makes about a pint, which is a good starting point.
  • 2 cups milk
  • ¼ cup powdered milk (if using low-fat milk)
  • 2 rounded tablespoons yogurt
  1. Let milk (along with powdered milk, if used) simmer gently for about 15 minutes, stirring the pot gently several times to prevent sediments from sticking to the bottom. Set the milk aside until it gets to the right temperature (around 110°F/ 45°C). A thermometer will be handy when you first start experimenting but after a while you may just follow the rule of the pinky, as yogurt-makers have been doing all along: Give the milk a gentle stir to distribute heat and dip your little finger in the milk, The temperature is right when you are able to count up to 10 before you feel a gentle sting of heat.
  2. Add some of the warm milk to the yogurt, mix and pour into the warm milk. Give it a gentle but thorough stir. Then, cover the pot and set it aside and cover as described above. When set, refrigerate and use.
If yogurt fails to curdle and set, it could be that milk was not warm enough to begin with, or the place itself was not warm enough. The remedy is to expose it to more warmth. Put it on top of a warm stove, or in a barely warmed up oven. However, if it looks lumpy with noticeable curds and lots of whey separation, it could be that milk was a bit hot, or the place where it was kept was too warm. The best way to deal with it is to turn it into thick yogurt (Arabic labne, more popularly known as Greek yogurt) thus: Line a small colander with 3 to 4 layers of cheesecloth or a coffee filter. Fit the colander into a bowl, and add the yogurt, and drain it for several hours until it becomes thick. Let it drain in the refrigerator if you do not want it to be tart.



Photos by Nawal Nasrallah

Nawal Nasrallah

Independent Iraqi scholar, passionate about cooking and its history and culture. She was a professor at the universities of Baghdad and Mosul, teaching English language and Literature until 1990. Her cookbook, Delights from the Garden of Eden: A Cookbook and a History of the Iraqi Cuisine, was a Gourmand World Cookbook Award winner and was chosen as one Saveur Magazine’s favorite cookbooks of 2013. Her recipes have been featured in The New York Times, The Boston Globe, and Food and Wine. She lives in Salem, NH.