Fermenting Milk – Making Yogurt At Home

I don’t drink a lot of regular milk. It probably goes back to the days when I felt I was being “force fed” milk when I spent months and months in a hospital, and was prescribed up to 36 aspirin tablets a day. The milk was supposed to coat my stomach and protect it from the ASA – and I grew to disliking milk.

However, later in my life, I worked on a dairy farm and loved the taste of fresh, whole milk just hours after it had been produced from the cows and cooled down. But it is illegal for me to acquire fresh raw milk where I live.

So while I don’t particularly like store bought regular milk, I do enjoy fermented and cultured dairy products like buttermilk, yogurt, kefir and cheese. In fact, I could easily drink a litre of buttermilk or eat a half of a 650 gram container of yogurt in one sitting. At over 4.00 a container, the price can add up. And I’ve always wanted to try making my own yogurt at home.

Some time ago, I began to do some research and was astonished at just how easy it can be to make yogurt. However, I did run into a few problems the first couple of times I made it but since then, have perfected my yogurt making at home.

The first few times I made it, my yogurt came out thin and was more like a yogurt drink than a thick yogurt. And I think I know why that happened. I had read somewhere that it was necessary to heat the milk beforehand to a temperature of about 180F in order to modify the protein structure in the milk, but another person who claimed to be a biologist indicated that this was not tr

ue; that the only reason one needed to heat the milk that high was to pasteurize it and kill any wild bacteria that might be in the milk.

So, the first few times, I didn’t pay much attention to how hot I heated the milk. I have since learned that this step is very important to ensure obtaining a product that is a thicker yogurt instead of something that resembles more clabbered milk.

You can use any kind of milk including whole milk, 2% or skim. I prefer whole milk (what we call here in Canada “homogenized” or “homo milk” for short) and it contains 3.25% butter fat. I’ve also used goat’s milk in making a true “Greek Yogurt” which has a slightly different taste but it’s not that much different in my opinion from using cow’s milk.

In Ontario, 4 litres (the equivalent of a US gallon) of milk comes in plastic bags. There are three bags to 4 litres which means each bag contains about 1.33 litres (about 0.35 US gallon).

So, here’s what I do to make yogurt at home:

1. Empty a bag of milk into a Corningware dutch oven.

2. In order to get the milk to a temperature of about 180F, I microwave that amount of milk for about 12 minutes and 30 seconds. It took some experimentation using a candy thermometer to get the right amount of time in the microwave. Now I don’t bother with the thermometer.

You could heat your milk in a heavy bottomed pot on the stove to just below the boiling point, but I’m afraid of scalding or burning the milk so I don’t do that.

3. I have found it takes about 30 minutes for the milk to cool down to about 110F. Wash your hands well and stick your pinky finger well into the milk. If you can hold it there for 12 seconds, it’s about the right temperature. Be sure to not let the milk cool down too much. You want it at about 110F.

4. During the 30 minute cooling stage, I take out about half a cup of yogurt out of the fridge and let it sit on the counter which warms it up. This allows the active bacteria present in the yogurt to become – well, active!

5. Turn your oven on and watch the temperature. Turn off the oven when it reaches about 110F. Turn on the oven light.

6. There will be a thin skim on top of your warmed milk. Using a fork, remove it. You can eat this if you want, or discard it. I give it to my dog as he loves it. Then, mix some of the warm milk with the half cup of yogurt that has been warming up.

7. Stir the mixed yogurt and milk into the dutch oven. At this step, you are inoculating your yogurt with a ’starter’.

8. Put the lid on the dutch oven and set it at the back of the oven, near the oven light. Leave for 6 or more hours. The longer you leave it, the more tart your yogurt will taste. Personally, I like tart and have been known to leave it in the oven for 12 hours.

9. After at least 6 hours, you can check your yogurt. It should be firm with a clear liquid visible on top and around the sides perhaps. The liquid is whey, which you can stir back into the yogurt after you have refrigerated for several hours.

Yogurt Making Tips And Requirements

1. You will need a yogurt starter that contains active bacteria. In order to obtain this, you can purchase a good yogurt that lists “active bacterial culture” on the ingredients.

2. Many say that you cannot use flavored yogurts as your starter. This is not true in my experience. However, be aware that these yogurts, along with added flavors, also often contain fillers like gelatin and bean gum in order to thicken it. You will have better results using a plain or Greek Style yogurt that is unflavored.

3. You can use half a cup of your homemade yogurt as your next starter if you want. If you are going to flavor your yogurt, set this amount aside and keep in the fridge for your next batch of yogurt, up to a week from now.

4. If you want to flavor your homemade yogurt, you can. Add berries, fruit, or whatever you like. My ten year old son loves vanilla yogurt and I added about three tablespoons of sugar to about 325 grams of yogurt and then stirred a teaspoon of pure vanilla extract. He thought that was delicious! You could also sweeten it with honey as an alternative to sugar.

Update (October 26, 2012):

My cousin, Heather Brunet, reported that she was able to make yogurt in her rice maker, after following the above steps but instead of a warmed oven with the oven light turned on, substituted the rice maker. She used the “warm” setting which seems to have kept it at the right temperature for the bacteria to multiply.

Yogurt Making – What’s Going On?

Turning milk into yogurt requires a fermentation process. Unlike wine, where fermentation is carried out by yeast, the lactose in milk is fermented by bacteria. The strains of bacteria that are most common are Streptococcus thermophilus and Lactobacillus bulgaricus. Some commercial yogurts may include additional strains.

Like winemaking, where yeast ferment sugars in the juices, yogurt making is where bacteria ferment the lactose in the milk. Lactose is simply another form of sugar, and in yogurt making, is converted during the fermentation process to lactic acid, glucose and galactose. This makes yogurt a food that is often easily eaten by those who are lactose intolerant.

Because the fermentation process increases the acidity, this makes it more difficult for other bacterias to take hold in bacteria and was used by people of different cultures as a way to preserve milk before refrigeration existed.

Health Benefits Of Yogurt

Yogurt is known to be a very healthy food and contains vitamins B6 and B12, riboflavin, calcium and protein. When strained, the whey contains a “whey protein” which is known to be an excellent source for the human body and easily used.

In addition to the nutrients, the bacterial culture in yogurt adds to the digestive flora in a very friendly manner. Some believe that regular yogurt consumption can add years to life.

Eating And Using Yogurt

While many people enjoy eating yogurt plain, some do not like the tart taste of it on it’s own. For those, there is nothing wrong with sweetening your yogurt with a little sugar or honey. As well, additional flavors can be introduced with the addition of fruit. Some like to add berries while others enjoy mixing in bananas. You can add just about anything you’d like.

Yogurt though, has many many more uses and it occurs on the ingredient lists of many recipes. Shortly, I’ll provide some of my own recipes for yogurt based foods including Tzatziki Sauce, Tahini Sauce, Yogurt cheese, and Greek Style strained yogurt. I’m also experimenting with making Jameed, a dried and hardened form of yogurt made from goat’s milk and popular in Jordan.

Commercially available frozen yogurt does not always contain active bacterial cultures but you can flavor and freeze your homemade yogurt and still have the health benefits of the active cultures. Freezing the yogurt puts the bacteria in a dormant state, but they are then reactivated when they are consumed as frozen yogurt and become active again. My son enjoys the “yogurt popsicles” that are often made and are very easy to do.

Yogurt certainly is a food that is not only healthy but there are just so many ways to use it. Making your own is also very easy and for me, economical. Considering that a bag of milk, or one third of a US gallon will more than fill a standard size container that yogurt is purchased in (650 grams or about 6 1/2 cups) the supermarket for about 4.49, home made yogurt is less than a third of the price.

Happy yogurt making!

MORE:

How To Make Greek Style Yogurt

 

1 Comment

  1. Jen McCarthy on November 15, 2012 at 5:46 pm

    Awesome article – and great idea to make your own yogurt at home. We’ve been doing that for years and except for when yogurt goes on sale, it does save a good chunk of money. For those that like it sweetened, instead of sugar, try a little honey instead.

    Our kids love that! And sometimes a couple of drops of pure vanilla extract.

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