Tuesday, December 21, 2010

Homemade Yogurt

Yogurt is simply the byproduct of milk fermented by bacteria; it has been made and eaten by people for over 5000 years and is enjoyed in condiments/sauces such as raita, drinks such as lassi and smoothies, and strained into cheeses. Yogurt is rich in calcium, protein and vitamins; the live cultures it contains are known to aid digestion and regulate the body's processes.

Nowadays, yogurt commercials are everywhere on TV, all touting their special probiotics and their health benefits. Unfortunately, most store-bought yogurts are full of added ingredients such as pectin, gelatin, high fructose corn syrup and more. These products all tout their ability to restore regularity, but any good yogurt containing live, active cultures will do the same. The added sugars are completely unnecessary - a single container of Yoplait Original yogurt contains nearly 3 times the sugar content of a single Krispy Kreme original glazed doughnut (27g of sugar compared to 10g).

mmmm...tricalcium phosphate....

Some of the commercials are also questionable at best...

Yogurt is incredibly easy to make at home; you simply inoculate milk with the live cultures, incubate the bacteria for several hours, and refrigerate. Commercial yogurt makers are available in stores for a reasonable price; all they do is maintain the proper temperature of about 110 degrees to allow the bacteria to ferment the milk. 

Homemade Yogurt
1 quart milk (do not use UHT milk)
2 Tbsp plain yogurt with LIVE, ACTIVE cultures

You can use skim, lowfat or whole milk for making yogurt. I am using local, organic whole milk, which has not been homogenized but has been pasteurized (as required to allow sale). As long as the milk has not been Ultra High Temperature processed (UHT), it will work. Keep in mind, however, that homemade yogurt is runnier than storebought (due to the lack of thickeners such as pectin or gelatin). The higher the milk's fat content, the creamier and thicker the yogurt will be. You can also add 1/2 cup of dry milk powder to the milk before heating to yield a thicker yogurt. I personally have never added any milk powder to mine, though. 

For starter yogurt, any good plain yogurt that contains live, active cultures will do. Stonyfield Farm makes an organic plain yogurt that can be found at most grocery stores. Unfortunately, their yogurt does contain added pectin. Fage (pronounced "fah-yeh") is an excellent Greek yogurt and is my trusted standby for starter culture. Fage only uses milk from non rBGH-treated cows and live active cultures. Dannon Greek is a great and affordable option as well (best of all, like, Fage, it only contains 2 ingredients - milk and active live yogurt cultures). 

Only 2 ingredients are needed...

Live Active Yogurt Cultures are a must...

Having a good, accurate thermometer is required, as you will need to carefully monitor the temperature of the milk. Gently heat the milk until it reaches 185 degrees and begins to froth; you can use a double boiler to prevent scalding. At this temperature, the whey proteins in the milk will denature and coagulate to yield a thicker yogurt.

Meanwhile, prepare an ice bath; make sure you have a container that will fit the pot used to warm the milk (for me, this means using the kitchen sink).

Once the milk reaches 185 degrees, remove it from the heat and place in the ice bath. The milk needs to cool to 110 degrees; the optimal temperature for the bacteria to ferment the milk. The ice bath is not mandatory, but speeds up the cooling process considerably.

Next, inoculate the milk with the yogurt culture. The general rule is to use 2 Tbsp of yogurt for every quart of milk. Stir gently to combine the yogurt and the milk. 

The measurements don't have to be exact...

Once the milk has been inoculated, it needs to be kept at the optimum temperature of 110 degrees to allow the bacteria ideal conditions to ferment the milk into yogurt. 

Commercial yogurt makers are inexpensive and often found at thrift stores and yard sales.

Most yogurt makers will also fit a quart-sized mason jar. Use a wide-mouth jar to make the yogurt easier to remove from the jar.

The inoculated milk is ready for incubation...

Since the mason jar doesn't fit perfectly into this maker, I add warm water to fill the gap.

Place the lids on and make sure the makers are plugged in; I made this mistake once before...

If you do not have a yogurt maker, you can easily maintain the correct temperature by using a slow cooker, heating pads, towels and a cooler, or even by placing the yogurt inside a gas oven heated by the pilot light. The yogurt should be done after 6-8 hours; the milk will thicken, develop a skin and yellowish whey will be visible on the top. 

Whey is clearly visible, as well as a skin atop the yogurt. 

This batch has a cream top due to using non-homogenized milk. 

At this point, the yogurt will need to cool; place the yogurt in the refrigerator for another 8 hours to chill completely. The yogurt will thicken further and be ready to eat.

Once chilled, if desired, the yogurt can be thickened further by straining out the whey through a layer of cheesecloth. The whey is very healthy and can be saved to use for making rice or baking biscuits, combined with fruits for smoothies, or even fed to pets (my dog loves it on top of his food). Leftover whey can even be used for making homemade ricotta or cream cheese! 

I drained this batch by tying it up in several layers of cheesecloth and suspending it over a bowl in the refrigerator for about 8 hours. Once drained, it had the perfect texture of thick, Greek yogurt.

Enjoy your yogurt with fruit, honey, or any other desired toppings. You can reserve a few spoonfuls of this yogurt as a starter for your next batch; after 3-4 batches, however, you will need to start with a new, fresh starter.

Strained homemade yogurt topped with local honey and local pecans.


  1. Julia, I wanted to let you know that this recipe actually works for chowstalker.com, so if you get a chance to resubmit it with one of the photos without the honey, I'd love to publish it!

  2. Thanks, Patty! I've submitted a new image!

  3. Can you give step by step directions for making this yogurt in a slow cooker??? This would be great thanks!!

    1. Sorry, but I do not have a method for making yogurt in a slow-cooker. Even on low heat, a slow-cooker is going to get too warm; this will kill the bacteria.