Eco-Saturday: Crock-Pot yogurt

Making your own yogurt is a good way to save money and cut down on packaging at the same time — and this method is so easy, you’ll never bother with store-bought again, especially after you taste the homemade stuff.

Ingredients
Half-gallon of milk
Half-cup of plain yogurt

Equipment
Slow cooker
Candy thermometer
Whisk
Towels
Oven

This is really challenging: You have to pour milk into a Crock-Pot.
This is really challenging: You have to pour milk into a Crock-Pot.

Dump the milk into your slow cooker, turn it on high, and ignore it. About two hours in, start checking it with the candy thermometer every 15 minutes until it reaches 180 degrees. That temperature will kill off any unwanted strains of bacteria that might be floating around in there.

When the milk reaches 180, shut off the slow cooker and ignore it some more. After about two and a half hours, start checking the temperature until it reaches somewhere between 105 and 115 degrees. That temperature is warm enough to incubate yogurt.

Save back a half-cup of this batch of yogurt, and you can use it to inoculate the next batch so you don't have to buy more.
Save back a half-cup of this batch of yogurt, and you can use it to inoculate the next batch so you don’t have to buy more. You can do that for two or three batches before the cultures start to wear out.

When the milk is between 105 and 115 degrees, whisk in half a cup of plain yogurt.

The towel helps hold in heat.
The towel helps hold in heat.

Remove the crock from the cooker, wrap it in towels, and set it in the oven. Turn the oven light on and leave it overnight. (Alternately, you can pour the milk into canning jars, close the jars tightly, and put them in a small cooler. Run hot tap water in the cooler up to the lids of the jars, close the cooler, and leave it on the counter overnight.)

You can make yogurt in a stockpot, but it sticks to the bottom and makes a horrible mess. The Crock-Pot is much easier to clean, as the milk doesn't burn on.
You can make yogurt in a stockpot, but it sticks to the bottom and makes a horrible mess. The Crock-Pot is much easier to clean, as the milk doesn’t burn on.

In the morning, your milk will have turned to yogurt. Whole milk will generally produce thicker yogurt than skim, but you can adjust the thickness by straining the finished yogurt.

Homemade yogurt may look thin at first because it doesn't have gelatin or artificial thickeners in it.
Homemade yogurt may look thin at first because it doesn’t have gelatin or artificial thickeners in it. Straining thickens it up.

If you want Greek yogurt, line a sieve with a clean tea towel and set it on top of a bowl or pan.

About half the yogurt's volume is whey.
About half the yogurt’s volume is whey.

Dump the yogurt into the sieve and let it drain in the refrigerator until its volume has reduced by about half.

After straining. Much thicker.
After straining. Much thicker.

Store in a sealed container in the refrigerator and use in smoothies or serve with granola and fruit. If you’re vegetarian or just trying to lose weight, Greek yogurt also makes a good low-fat way to sneak some extra protein into your diet — just stir in some ranch dressing mix and use as you would sour cream.

You can also make a tangy substitute for cream cheese by straining your Greek yogurt overnight.

Emily