Homemade yogurt - simple, green, frugal

I don't remember ever eating yogurt as a kid, but as an adult, I came to really enjoy it. Not only is it naturally sweet and creamy, but it's so wonderfully good for you. I began eating it about 10 years ago for the bacteria. (I have had a digestive disorder since I was 18 and at some point, someone suggested that the bacteria (probiotics) in yogurt might help with my tummy trouble).  I'm not sure how much it has helped my tummy over the years, but I loved the taste and have continued to enjoy it.

The evolution of my yogurt experience kinds goes like this:  At first, I was enjoying all those yummy Yoplait flavors until I noticed all that extra sugar. Hmm. It occurred to me that I could probably add my own fruit (and actually get a fruit serving out of a yogurt snack in the process) on top of the fact, that I was just learning at the time that organics are better for you anyway.

Our grocery carries Stonyfield Farms Organic yogurts, so I picked up a quart of plain low-fat yogurt to see how I liked it. I'll admit, it took me a long while to get used to the taste of plain yogurt (I was accustomed to all that extra sugar), but I can't eat anything else now (the other is way too sweet) - my favorite way to eat yogurt (when it isn't plain) is to mash up a banana in the bowl first, then add some yogurt in and mix it all together. Absolutely delicious! But I digress.  

So I was buying all these quart containers and I was starting to worry about what to do with all of them. They are #5 plastics after all, and we can't recycle those here in town. But at the same time, I refused to throw them away. Just about the time I learned that Stonyfield Farms will take them back (you have to mail them off), I decided to take the big plunge and try to make yogurt myself. 

I searched and searched and searched the internet and it seems like everyone makes their yogurt just a little differently. It was the incubation part that kinda stressed me out. It seemed really complicated and easy to screw up and I was nervous about trying. As it turns out, it's SUPER easy!  I've tinkered with the process here and there and eventually found a process that works for me.  Here goes....

Heat the Yogurt

Supplies:

• 1/2 cup whole milk yogurt - this is what's called the starter because it already has the bacteria in it (I've also used low fat yogurt and it works just fine. I buy the whole quart container and freeze 4 or 5 starters for future yogurt making days. The frozen starters will keep 2-3 months in the freezer. Unfortunately, the only way to  know if the starter has gone bad is to make yogurt, and after it's all said and done if it hasn't thickened properly then you know the bacteria died and you have to buy new starter)
• 1/2 gallon whole milk (I've always used whole milk - if you use anything less, you'll probably need to add some powdered milk as a thickener. There are tons of recipes on line if you search)
• sauce pan
• measuring cup (1/2 cup or so)
• spatula
• thermometer
• 2 quart size containers

Put the 1/2 gallon of milk in a saucepan and heat to 180 degrees using the thermometer as a guide. (As the milk is heating, go ahead and set aside your 1/2 c. yogurt starter on the kitchen counter so that it warms to room temperature). Once your milk reaches 180 degrees, take the milk off the heat source and allow to cool to 115 degrees. This takes  about an hour. As it cools, you may notice a crust forming on the top. Just skim this off with a spatula and discard.  NOTE: temperatures above 120 degrees will kill the bacteria so be patient and let it cool.

Once the milk has cooled to 115 degrees, use the measuring cup to remove about 1 c. of warm milk. Pour this warm milk into the container that is holding your yogurt starter. Mix with the spatula to combine thoroughly. Once the 1 c. of milk is combined with the starter, pour the mixture into the rest of the milk in the saucepan and stir with the spatula to evenly distribute the yogurt starter/bacteria (just a few seconds, really).  Take your measuring cup again and scoop all the milk/yogurt starter mix into each of the two quart sized containers. They'll be full.  Put the lids on and get ready to incubate.

Incubate Your Yogurt

Supplies:

• bucket/trash can/kitty litter box - whatever (I use an old kitty litter box)
• heating pad
• towels
• thermometer

Lay a towel in the bottom of the kitty litter box to help insulate the bottom.  Line the inner walls with the heating pad and turn it on to warm it up.  When your yogurt is ready, place your yogurt containers inside the kitty litter box and wrap the edges of the heating pad snugly around them. Place the cord end of your thermometer inside the box, close to the yogurt containers so that you can keep an eye on the internal temperature. 

Tuck the second towel into the kitty litter box to make sure everything inside is nice and insulated and use any extra towel parts to cover the top. If your kitty litter box has a lid, put it on top (mine doesn't close entirely because I have the thermometer and heating pad cords hanging out but that's ok. The idea is to keep as much heat inside as possible).  

Here's where you need to be vigilant.  Watch the temperature for 15 minutes or so to make sure it stays within 105-120 degrees - too low and the bacteria will hibernate, too warm and they'll die). Once the temp on the thermometer stabilizes, just let the incubation happen. I rarely leave the house while I'm incubating (maybe just a short walk or working in the yard) just so that I can keep an eye on it. Also, the heating pad that I have shuts itself off after 2 hours so every two hours I have to turn it back on and make sure things don't get too warm in there. It takes a time or two, but you'll get the hang of it and gain confidence enough so that you're not hovered over it the entire time. In the mean time, do laundry, read a book, harass your kids, you know, whatever sounds good.

I let my yogurt incubate for 5-6 hours. Some people do it for as little as 3 hours, other for up to 12 hours. Five to six seems to work just right for me.  

Chill the Yogurt

Once your yogurt has incubated, take your yogurt containers out of the kitty litter box.  I put them on the kitchen counter, open them up just to make sure they've thickened properly (won't be desired consistency yet, but it should look like a big gelled glob), then put them in the refrigerator overnight. By morning, your yogurt will be ready to eat. Enjoy!

Notes

You can use a sample off the yogurt you just made as a starter for the next batch (called a 2nd generation starter).  It will taste just as good. I've found that when you get to a 4th generation, the starter has degraded enough that you lose the creaminess. I only make yogurt every couple weeks at the most so I usually just pull a 1st generation starter from the freezer (thaw overnight in the fridge before use).

So that's it! Yummy, creamy homemade yogurt with no additives, preservatives, or extra sugar, and a perfect base for your favorite fruit. As far as cost comparison, 1 qt of organic yogurt costs $3.75 in our grocery store. I can make 4 quarts from a gallon of milk ($10 a gallon at the dairy), so I'm definitely saving some money here (frugal). And you can just keep reusing the store bought yogurt containers to make more yogurt, use them to save the extra starters in the freezer, store your homemade ice cream, use them to make seedlings for your veggie garden.....the possibilities for reuse are endless (green). Of course, you can also brag about how ingenious you are for making your own yogurt while your nibbling on that yummy homemade snack. Enjoy!