Food in Jars Mastery Challenge – When the stars align: fermenting free milk

Making yogurt!

This month’s Food in Jars Mastery Challenge was all about using fermentation to preserve food. Despite the health benefits provided by fermented foods, I have never really been a fan. At least I wasn’t a fan until I realized that both sour dough bread and yogurt rely on fermentation to develop their unique flavors. And then my neighbour gifted me with a jug of milk that would go bad before she returned from her travels. Clearly the universe was telling me to make yogurt.

The making yogurt at home is very simple. There are tons of tutorial on the internet, some of which I have linked to in the section discussing incubators. Because I was limiting my time on the internet this week, I used the instruction in my copy of The Tightwad Gazette III.

Ingredients and Equipment:

Milk.  I have only used cow’s milk to make yogurt so I can’t comment on making yogurt from other types of milk. Other people have, and you read about some of their experiences at these links:

Skim milk powder (½ cup per liter or quart of milk (optional)): Skim milk powder can be added to thicken the yogurt, but it is optional. In Canada, instant milk can be expensive. If I didn’t have any in my pantry, I would not have used it.

Yogurt with live cultures (2 Tablespoon per liter). Using yogurt with live cultures is very important. It is the bacteria or cultures that turn milk into yogurt. Without these microscopic critter, you will end up with jars of cooked milk.

Check the ingredients. You must use yogurt withe active cultures!

A heavy pot large enough to hold the milk and a spoon to stir it with

A candy thermometer. In the past I use to make my yogurt without a thermometer, so it is possible, but it is not as reliable.

Clean glass jars and lids, ladle and a funnel (I used my canning funnel)

An incubator. You will need a way to keep the milk/starter mixture warm so that the cultures can grow. There are several ways to incubate yogurt:

Use a cooler:

Use your slowcooker:

Use your food dehydrator:

This article gives a nice summary of several different methods:


  • Dump the milk into the pot and add the skim milk powder (if using). Stir until the powder is dissolved. Heat until the milk reaches 180°F. This means the milk is almost boiling but not quite. If you stick your finger in it, you will say, “@$##$ that’s hot,” but you won’t get burnt. Bringing the milk to this temperature kills off any bacteria that will compete with the active cultures and inhibit their growth.
  • Remove the pot from heat and allow to cool to 110 – 115°F or “blood warm.” Before I owned a candy thermometer, I used to test it in the same manner you would test the temperature of baby formula by dripping some on my inner elbow.
  • Gently stir in the yogurt starter. Add the yogurt and whisk with vigor!
  • Quickly ladle the mixture into jars, seal and incubate for 6 – 12 hours.
  • When the yogurt has solidified, store in the fridge for a week or so.

This article provides a good summary of the process of making yogurt, several good tips, and a wealth of yogurt related information:

Homemade yogurt


The Results:

A breakfast full of creamy white goodness.

I got 4 pints of homemade yogurt. I could have gotten 8 pints, but I wasn’t on the ball and I messed up. The following cost breakdown is based on ½ of the recipe I used or the amount needed to make approximately 4 pints of yogurt.

The Cost:

Ingredients Cost (November 2017)
2 liters of homo milk $3.79
1 cup (125g) of Skim Milk Powder at $1.59/100g) $1.98
4 Tablespoon or ¼ cup of Yogurt with live cultures ($3.99 for 650 ml or 2.25 cups) $0.45

Cost per batch


Cost per ½ cup serving


Cost for a container (650ml or about 2.25 cups) of yogurt at my little store = $3.99 or $0.99 per ½ cup serving. As you can see from the table above, it is much more economical to make my own.

What I learnt:

I used to make yogurt all the time when my kids were young, but it has been years since I turned out my last batch. I will admit that I am out of practice and my batch did not turn out as well as I had hope but the lessons I learnt (relearned?) means that future batches should be more successful.

  1. Have your incubator ready to go. My house is really, really cold until we light the fire. I was worried about keeping my yogurt warm enough. I was going to use my dehydrator to incubate my yogurt because I knew it would give me the ability to maintain a warm environment, but I over looked the critical fact that there was no way I was going to fit my jars in the dehydrator. This should have been obvious (so obvious it’s embarrassing to admit). Happily, I remembered that we had a small, lunch box sized cooler in the shed. The Man found it and scrubbed it down while the milk cooled. It fit four jars nicely and it worked well even though I forgot to add hot water. I jury rigged an incubator out of a large pot and towels, which didn’t work. I lost about half of my work because the milk/yogurt mix didn’t remain warm enough to let the yogurt culture grow. Next time, I will pay more attention to my equipment.
  2. I also recommend thoroughly mixing or whisking the yogurt starter through the yogurt as per The Tightwad Gazette. There is some debate in the online yogurt making community regarding how to add the starter to the milk. I erred on the side of gentleness. As a result, I ended up with clumps of starter on the bottom of my pot. This may have contributed to my yogurt failure.
  3. I also learnt that yogurt might give you super human abilities to withstand the cold – while Icelandic yogurt anyways.

Will I do it again?

Absolutely. Without question.

I am going to look for ways to store yogurt starter for future use. I tend to go on yogurt eating jags so I don’t always have some in my fridge to use as starter. I have heard that you can freeze or dehydrate it. I guess I have another future experiment.


  1. Just a side note on ultra pasteurized and UHT milk in those long life cartons.
    I’ve not yet seen a recipe noting to beware using these in yoghurt making, but I have had very negligible to no results using them. I have tried several different brands. I am an old hand at yoghurt making and these have been my only disasters since the late 60’s.
    I have to assume that the high heat process which kills all bacteria to enable the long shelf/refrigerator life also kills anything viable in the milk which would enable it to culture.
    I would be interested in how others have fared if they have used them.


    1. You are right, I have heard that ultra pasteurized or UHT milk will not work. I didn’t even think about mentioning it, maybe because it is not very common in Canada. I am going to agree with you. I would think that the heat used to sterilized the milk creates an environment in which nothing will grow. Hmmmm, kinda scary when you think about it.


  2. Freezing works for me. I use an ice cube where each cube is approx 2 tablespoons. Once solid they go into a hefty plastic bagn for storage.


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