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Step-by-Step Homemade Yogurt in a Thermos

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Cat's upbringing and experience working in areas of holistic health inspires her to embrace a healthy lifestyle and diet-as much as possible

Perfectly beautiful and creamy yogurt

Perfectly beautiful and creamy yogurt

Why Not Make Your Own Yogurt?

The topic of making yogurt came up while visiting my mom in Virginia for Mother’s Day. I live in Puerto Rico and was telling her about some of the things I don’t buy as much anymore because of availability, cost, and my starving artist budget. Greek yogurt was one of those things I missed dearly. Mom, who raised me on homemade bread and butter, suggested I make my own darn yogurt and set out to find out how. Within a couple of hours, she found multiple recipes as well as a thermos, and we set about creating the recipe below. I should add that it turned out perfectly the very first time.

First Things First

If you want a successful yogurt-making session, it's important to get organized first.

After thoroughly washing your hands to prevent the spread of bacteria, gather all of your clean supplies and ingredients. You want to have everything at your fingertips so as not to be searching for things while you should be watching the temperature.

Ingredients

  • 2 1/2 tablespoons of starter yogurt at room temperature. We took our starter yogurt from a container of unopened Greek yogurt we already had in the fridge. You can use any yogurt you like—just be sure it's unopened.
  • 3 cups milk (skim, whole, or low-fat)

Necessary Equipment

  • 1-quart thermos with lid. We used a Stanley stainless steel thermos because it does a great job of maintaining temperature consistency.
  • Measuring cup
  • Tablespoon
  • Medium-size cooking pot
  • Cheesecloth
  • Strainer
  • Thermometer
  • Small bowl

Yogurt Cultures Need a Warm Environment to Grow

The only purpose for adding hot (but not scalding) water to the thermos is to maintain a warm and cozy environment necessary to grow yogurt cultures. No need to gauge the temperature. Just be sure it's hot but not hot enough to burn YOU.

Step 1: Warm the Thermos

Fill the thermos with very warm (not hot) water, put the lid on, and set aside while completing the following steps. The yogurt needs to be kept warm while growing.

Step 2: Bring Starter Yogurt to Room Temperature

Measure 2 ½ tbs. yogurt into the small bowl (set aside to get to room temperature between 0-72 degrees).

We gently stirred the yogurt until the battery-operated thermometer registered 70 degrees.

step-by-step-directions-for-homemade-yogurt

Step 3: Heat the Milk

Measure 3 cups milk (skim, whole, or low-fat) into the pot and warm on a medium setting to 185 degrees.

We used whole milk for a creamier yogurt, but you can use whichever suits your personal tastes. Heating gradually to 185 degrees kills bad bacteria and also gives your freshly made yogurt a nice texture—not too thin or thick. Once you master making your first batch of yogurt, you can increase the milk and starter yogurt for larger quantities.

step-by-step-directions-for-homemade-yogurt

Step 4: Cool the Milk

Cool the milk to about 100 degrees, but definitely not higher than 112 or lower than 99.

Ours was slightly higher than 99 degrees, but it was also a cold day and it still turned out great.

step-by-step-directions-for-homemade-yogurt

Step 5: Combine and Transfer

  • Empty water from thermos.
  • Pour about ½ cup cooled milk into the bowl of starter yogurt to blend well.
  • Pour blended milk and yogurt back into the pot of milk and stir thoroughly.
  • Pour blended milk and yogurt into the thermos.

Whew! There are four transfers here. Good job! After this, you can relax.

Pour blended milk and yogurt into thermos

Pour blended milk and yogurt into thermos

step-by-step-directions-for-homemade-yogurt

Step 6: Let Sit for 8 Hours

  • Cap the thermos and keep in a warm place.
  • Wrap with a towel if cold. We needed to do this step because it was cold. Our thermos of yogurt looked like a ghostly Halloween decoration.
  • Don't move anything!
  • Let it all sit for 8 hours.

It works out really well if you begin the process either in the morning or before retiring for the night. Getting up to check on yogurt shouldn't be a part of this experience.

Step 7: Strain the Yogurt

8 hours later, carefully pour the mixture through a strainer lined with cheesecloth and allow the liquid to strain over a bowl for 1-2 hours at room temperature. For thicker yogurt, allow to strain for a full 2 hours.

Strain mixture

Strain mixture

Step 8: The Final Stretch

Once the mixture has strained for the appropriate amount of time, turn the strainer upside down over a small/medium-sized container and gently peel away cheesecloth before placing it in the refrigerator. Once the yogurt has chilled to your liking, you can leave it in the container it's already in or spoon it into a different one. We used a glass Mason jar.

If you like your yogurt with a little more flavor, you can add anything from honey to jams to your individual serving. We added lemon curd and it was phenomenal! Now you can enjoy any variety of yogurt your heart desires!

Cheesecloth peeled away from yogurt

Cheesecloth peeled away from yogurt

Comments

James on August 21, 2020:

Can you do the same with whole raw milk? (only heat to around 37C, which is 98F, in step 3)

Cat Radke (author) from Puerto Rico on April 22, 2020:

Greetings Karine and thank you for your question! I am glad you're going to make your own yogurt-who would have predicted a shortage? To answer your questions:

a. the water needs to be hot enough to keep the thermos warm which will in turn, keep the ingredients warm enough to grow into yogurt. We did not take the temperature of water. We filled it with hot tap water until the exterior was warm to touch.

b. Yes, empty water from water from thermos right before step 5 (I can't believe I didn't mention to empty the water out of thermos before adding ingredients! A revision is in order!).

c. We used organic whole milk. I have never used another kind. I don't know how powdered milk would work but it's worth a try. Not sure how the reconstitution of powdered milk would affect the outcome. If you do use it, I would love to know how it turned out. Also, if it isn't perfect the first time, try again because it's worth it. Mine turned out very good for the first time because my mom and I hovered over it, but we're a little OCD. And every other time I made it, it turned out good as well. Best of luck and thanks for your comment!

Karine on April 22, 2020:

Hello! Thank you for the recipe! Shops are short of yogurt, and so it is a very good occasion for me to try to make my own. I have three questions:

a. Under Step 1 of your recipe, you mention 'very warm water' but not hot. Any idea on the approximate temperature?

b. At what Step, should I remove the water from the thermos? Am guessing just before Step 5 right?

c. Are you using UHT packed milk? Have you ever tried with full cream powdered milk?

Thank you.