If you want to make yogurt like I do, you will need:
1/2 gallon of milk - I used 2%
1/2 cup of nonfat dry milk
4 Tablespoons of plain yogurt
Pint jars with lids
Cooler with lid
This recipe makes four pint jars of plain yogurt but can easily be halved if you don't want to make that much. Just cut in half all the ingredients!
First, wash and sterilize your jars and lids. You can do this by putting them in a pot of water and bringing it to a boil. Take them out and let them dry. Once they are completely cool and dry you can put the lids on and they will be ready when you get ready to make the yogurt. Or you can do this right before you make the yogurt.
Start with 1/2 gallon of milk. You can use skim, 1 %, 2 %, whole, goat, soy... I've used 2% but am going to try using skim since that's the kind of milk I usually buy.
Open the milk and pour out about 1/2 cup, drink it or give it to your kids to drink, put it in your coffee, or whatever you'd like. We're are just trying to make a little room in the milk container to mix in the dry milk.
Pour the dry milk into the 1/2 gallon carton and shake to mix. You will find it easiest to use a funnel to pour in the dry milk - this does give you one more item to wash, however. If you don't have a funnel, just carefully pour in the dry milk.
Another option is to leave the dry milk out, apparently it's not necessary but may give you a thicker yogurt. I had some in my pantry because I use it when I make bread so I used it for the yogurt.
Pour the milk into your clean jars, the 1/2 gallon container of milk will fill your jars almost to the top.
Put a washcloth in the bottom of a pot and add water. You can start with just a couple of inches of water; when you put in the full jars, the water level will rise in the pot. The water can be warm to fairly hot so you get a faster start on bringing it to a boil. Do not put in boiling hot before you add your jars though. When the cold milk in the jars comes into contact with boiling hot water, the jars will crack. The washcloth will keep the jars from rattling around too much when the water starts boiling. Clip a candy thermometer to the side of one of the jars. Place your jars into the water, you may need to add more water so that it comes up about 3/4 of the way up the side of the jars. Turn the burner on and bring the water to a boil. You want to bring the temperature of the milk up to between 180-185 degrees. It takes a while to bring the milk temperature up but you can do something else while they heat. Check the temperature occasionally. You don't have to stir them, they won't burn in the water bath.
Some recipes say that if you hold the temperature of the milk at around 180 for 1/2 hour, you will have thicker yogurt. Other say just to bring it to this point, no need to hold it there. I've tried it both ways and didn't notice any difference.
While you are waiting for the milk to heat, take out 4 tablespoons of plain yogurt. Each pint of milk will use one tablespoon of yogurt as a starter. I think my tablespoons were heaping. I've found measurements don't have to be precise. The yogurt should set out at room temp while the milk heats. I used Dannon this time but have also used Old Home brand. Just make sure it's plain yogurt. If you have homemade plain yogurt, you can use that too. Adding fruit and flavors comes after this whole process is complete.
After the milk has reached 185 degrees, take the jars out and place them in a bowl or sink with cold water. Don't throw away the water you used to heat the jars of milk in though. You'll need it later. If you see a skin on the top of the milk from heating, just remove it with a spoon. You can add some ice cubes to the cold water to cool it down faster. You need to cool the milk to between 105-112 degrees before you add the yogurt starter to the milk. That is temp at which the yogurt multiplies. The milk cools pretty quickly in the pint jars so you do need to keep an eye on it more closely now. If it gets too cool, just heat it up again.
At about 115 degrees, I take the jars out of the cool water, remove a couple of teaspoons of milk from each jar and stir it into the yogurt to make it smoother and easier to stir into the milk. When the jars reach about 112 degrees, I distribute the starter yogurt equally into the pint jars of milk and mix gently. Then put on the lids. If you have a big enough cooler, you can put the pot of hot water you used earlier into the cooler. If not, pour the hot water into a heat proof bowl in the cooler. Place a towel in the cooler and nestle your jar together on the towel. Cover the jars with the towel and shut the cooler lid.
Leave you cooler shut for 6 hours. Don't open it up to peek as you will lose heat. The hot water in the bowl or pot in your cooler will keep the yogurt warm enough to incubate.
After 6 hours, take the jars out, you will have yogurt. Put them in the refrigerator to cool and stop the process. You'll also have yogurt if you take the jars out after 5 hours because you are tired and want to go to bed.
The time in the cooler can range from 4 -24 hours, as long as the temperature is adequate, your yogurt will taste different based on how long it incubates. If you incubate your yogurt a long time, you'll probably have to add more hot water. There is plenty of information on the Internet about incubating yogurt in the oven, on heating pads and in crock pots. Yogurt making has plenty of room for experimentation.
Remember, this is plain yogurt you've just made, if you want it to taste like the fruit yogurt you buy in the store, you must add the sweetener and fruit. The good thing is that you control the amount of sweetener you add to your yogurt.
There are a number of things you can do with the yogurt you've just made. I have been eating it for breakfast with fruit and homemade granola. If you strain it through a coffee filter over a colander in the refrigerator, you can make a thick yogurt cheese, the yogurt cheese is wonderful for dips and desserts. You can add gelatin and fruit to make custard style yogurt. I use plain yogurt at least a couple times a month to marinate chicken for chicken tikka masala. I plan on sharing that recipe here someday, as it is one of my favorites.
This is the yogurt I made last night and enjoyed it this morning with cherries and honey.