Homemade Yogurt: In Six Steps

Homemade yogurt should be a staple in every kitchen. It’s healthy, versatile, delicious, and as we discovered five years ago, rather easy and fun to make. There will be a bit of the jitters the first time you ever make yogurt at home, but it gets easier and better every time after that. And like us, you will wonder where homemade yogurt had been all your life.

Before we get to the method, know that it takes just these ingredients and tools: milk, plain store-bought yogurt, 1-2 large cooking pots, a good mason jar with a lid, a wire whisk, a couple of big spoons, a towel, other dish towels, some foil, and tongs. What you don’t need to make homemade yogurt is a cooking thermometer or a candy or meat thermometer. We have never used any for making our yogurt, and recently in a cooking community post where we shared a little story about our no-thermometer method, an Indian lady shared—that it’s the same case in most Indian households. Yogurt figures a lot in Indian cuisine so they should know. Let’s get to it…

First some key things about the ingredients and tools:

The Milk

Buy whole (full-fat) cow’s milk. Not skim or reduced-fat or low-fat. And not UHT (Ultra-high-temperature) processed milk. For yogurt-making, we get our milk from the cold section, not the shelf. Our milk choice is whole milk from a local farm that’s been ultra-pasteurized. You may be able to make yogurt from UHT milk, but we have not tried it. We also have not used goat’s, sheep’s, coconut milk or soy milk or any of the nut milks to our make yogurt, and suggest that for a first try (unless you have dairy restrictions), you should stick to cow’s milk. Whole milk produces the thickest yogurt, which is exactly what we’re going for. *Ultra-pasteurized and UHT both mean that the milk has undergone some heat to kill pathogens like E.Coli. UHT just makes the milk last longer without refrigeration. Again for yogurt making, we use the ultra-pasteurized whole milk from the cold section. 

The Starter Yogurt

Get plain yogurt from the store (not Greek), to use as the starter for your homemade yogurt. Basically, you will be adding spoonfuls of this starter yogurt into your milk (4 tablespoons per liter of milk) to culture it and create your own yogurt. There’s a lot of pressure on this starter to be of good quality and freshness. And the way to do it is to pick the best product you can afford (preferably local) AND to check the expiration date. The farther away it is, the better. And plan ahead so the yogurt and milk you buy go from the grocery to your fridge in the least time possible without having to resort to a cooler during transport. Think about it this way: You have billions of those good guys, the good bacteria, in your starter yogurt, and you want to keep them alive and well for when they finally get to your milk. Lastly, don’t use flavoured yogurt which probably won’t work and will have additives like more sugar and what not. And no, the mango or strawberry in the yogurt won’t multiply in your homemade batch (someone had to say it).

The Tools

We suggest you begin with a liter of milk, which will make exactly a liter of yogurt (a liter of good store-bought yogurt costs a small fortune so imagine how much you’re saving) . Make sure your cooking pot is nice and heavy and big enough to hold the milk. Same with the mason jar. Get one big enough to hold the liter. It is ideal to have a second large pot that fits the mason jar to sterilise it, and to keep it in (upright) for the hours of fermenting.

HOW TO MAKE YOGURT

Step One: Sterilise 

Wash the mason jar and the lid well and put both in a pot with water. The jar can be laid down inside the pot on its side and the water should cover at least half of it. Boil for ten minutes. Turn of the flame and very carefully remove the jar (use the tongs) and lid from the water and let it air dry on a dish towel on the counter, bottom up. Again please be careful when removing the jar from the very hot water. Don’t skip this step. We never have, except one time—and that was the only time our yogurt came out runny and somewhat slimy. Yuck right? The jar is where your milk turns into yogurt and where you’ll be storing it until it’s consumed, so of course you want that clean and sterile. Somehow any contamination or bacteria in the jar just affects the end result. We also like to quickly sterilise the wire whisk and the spoons in the same pot of boiling water. If you can’t wait for the jar to air dry, you can wipe the inside of it using paper towels held by the tongs or wrapped around a spoon. It needs to be completely dry.

Step Two: Heat the Milk

In another pot, heat the milk on medium heat. Your milk is cold, and this will take anywhere from 10-12 minutes. But you’ll need to stand by and watch the milk closely. Keep your flame on medium so the milk never heats up too fast. The key is to heat it just until a skin begins to form, not quite scalding, and never boiling. It’s a good idea not to stir or disturb the milk while it heats up. You will likely notice the surface turning opaque and forming a skin, at which point, dip a spoon in the centre and lift it to observe if the milk coats the back of the spoon like this.

We usually watch for two things: some faint steam coming off the milk and the start of a skin forming before we dip the spoon to check. When it’s ready, immediately turn off the flame to prevent heating the milk any further.

The science is, that heating the milk up to this point (approximately 180 degrees F but again, we never check using a thermometer), allows the whey proteins in the milk to form a “stable gel”.

Step Three: Cool the Milk 

Once you turn off the flame, immediately transfer the milk into the sterilised and completely dry mason jar. Honestly, we just pour the hot milk straight away from the pot into the jar, which is admittedly precarious, and will result in a bit of spillage. You could always ladle the milk into the jar as well. But like your other tools, the ladle must be super clean. Here’s our just-poured hot milk in their sterilised mason jars.

You’ll notice again that the milk will form a skin on the surface and if you dip a spoon into it, it should look something like this…

We cover the mason jars loosely with some foil and leave it on the counter to cool for about 20-30 minutes. But this could take sooner or longer, depending on where you are in the world and your climate. Essentially, you want to cool the hot milk to just the right temperature for the good bacteria in the starter yogurt to grow. If it’s too hot or too cold, that won’t happen, and you won’t get yogurt. But no pressure right? Of course this can be daunting the first time, but it’s highly likely you’ll get it right, and go about it like a boss from there on. The method is simple: when about 20-25 minutes have passed we start checking the temp of the milk by simply putting both hands on the sides of the mason jar. Here’s a photo of that. The other hand was holding the phone to take this photo but you should have both hands on either side of the jar.

If you put your hands on the jar early after just pouring the milk, you will notice that it will feel quite hot, you’ll only be able to keep your hands on the jar for a second. As the milk cools you’ll be able to keep your hands there for longer. At the right temperature, it will feel COMFORTABLY WARM. It will feel like you could keep your hands on the jar forever, but it will be WARM. Let’s put it this way–put yourself in the shoes of the good bacteria (kaman you can do it). The milk should feel like a nice warm tub, you’d like to sink into. Not too hot, not getting cold, just perfectly warm.

Step Four: Add the Starter

When the milk is comfortably warm, take the starter yogurt out of the fridge, and whisk in 4 tablespoons of it into the milk.

Adding 4 tablespoons to one liter of cooled milk straight into the mason jar. And then whisking it gently to incorporate.

Step Five: Let it Ferment 

After adding the starter yogurt to the warm milk, cover the mason jar securely with its lid. You’ll then want to carefully put the jar into a big enough pot with clean and very warm (slightly hot) water that goes about halfway up the sides of the jar. Put the whole thing (it will be heavy and wobly) in a warmish and dark place (like the oven, turned OFF), where it can’t be bothered, and cover the whole thing (pot and jar) loosely with a towel. The towel helps to incubate your set-up and keep the warmth in. Here are our jars, in a pot with the water, after we put them in our oven (turned OFF), before we covered the whole thing with a towel.

Now the waiting begins. Leave your milk to ferment for 8 hours. We have tried waiting up to 12 hours, but found the yogurt to be too sour for our taste. And resist the temptation to keep checking on your set-up while it ferments. The less the jar gets disturbed the better. One time it was colder than usual in Manila, the water in the pot was no longer warm after only an hour. So without taking the pot out of the oven, we took one cup of water out of it, and added a fresh cup of warm/hot water to raise the overall temp a bit. But we have not found this necessary in our subsequent batches, and we basically just leave the milk until the 8 hours are up. If you really must check on your first try, check on the 4 hour mark. The milk should have thickened by then and you’ll notice this just by tilting the jar gently. Try to contain your excitement and leave it again for 4 more hours.

Step Six: Set the Yogurt in the Fridge

After 8 hours you can remove the pot from the oven and check on your yogurt. When you remove the lid, you should see your milk has thickened substantially and is tangy or pleasantly sour. It may have a small amount of liquid that separates from the more solid yogurt, this is whey. You could spoon it out and discard it, but you could also mix it in as whey is quite nutritious. The yogurt might still be somewhat warm after 8 hours of fermenting. The next thing to do is to put the yogurt (covered with the lid) in the coldest part of your fridge (not the freezer) to stay overnight to get cold and set even further. So given the 8-hour fermenting process and the overnight stay in the fridge, plan ahead. Our usual practice is to start the fermenting by 12 noon (Step Five), so it is done by 8pm. We then put it in the fridge overnight, so we have fresh homemade yogurt just in time for breakfast the next day. A photo of the last batch we made:

Now something important: If at this point, or even right after the 8-hour fermentation, your milk somehow remains liquid (has not set), tastes funny like it’s somehow too sour or acidic or not sour AT ALL, or is slimy in any way, and you just don’t feel right about eating it, then don’t. We have never gotten sick from our homemade yogurt, but we have from some store-bought ones. Just remember to not skip the sterilization step, to wash your hands before making the yogurt, and not to attempt making it if you are sick yourself. Also if your yogurt turns out great, remember it is best consumed within 2 weeks.

It sounds like a cliché, but it’s true. Once you taste your first batch of homemade yogurt, you won’t ever want to go back to store-bought yogurt again. It tastes a million times better–creamy, fresh, tangy, LUSH. With a beautiful mouth feel that you can’t beat.

Make it a couple of times and you’ll realize that it’s really not hard at all. From a health standpoint, you can choose your milk, your starter, and know that you’re not adding any harmful stuff. If you eat a lot of yogurt, you will also be spending MUCH LESS for better quality. Not to mention, you won’t be throwing away all that plastic packaging from all the store-bought single servings every time you eat yogurt.

We serve our yogurt with a drizzle of honey, a bit of fruit preserve mixed in, or topped with our favorite granola. We also use it in cooking, like in a marinade for chicken souvlaki or to make raita.

We usually make two liters at a time and go through one jar a week. Which means our yogurt keeps well for two weeks in the fridge. If you have any questions, leave them in the comments or send us a message in our social channels or through email and we would love to answer them.

Wishing you the best on your homemade yogurt adventure!