Yogurt-making
http://rebeccmeister.livejournal.com/782407.html

I have gotten into a couple of conversations recently about yogurt-making, so I thought I'd write about my method, so those new to yogurt-making have some ideas about what to do, and those who are more knowledgeable can contribute as well. (for instance, I know little about the life habits of the particular yogurt bacteria species, and little about competing species that might cause problems).

First, three things are quite helpful: a double boiler, a thermometer, and a heating pad (this one works quite well).* You will also need some milk (I'm partial to Organic Valley's whole milk), and some culture starter (I'm partial to Nancy's Yogurt, but you can use any tasty yogurt with live active cultures or some yogurt starter). Oh, and some containers for your cultures. I've been using quart-size canning jars, but you could use plastic if you feel like it and I won't be overly judgmental. This time.

Have your starter at room temperature as you get ready. One website that I read also suggested freezing a bunch of yogurt in an ice cube tray so you can use a cube or two at a time for making your yogurt. I tend to make about one batch of yogurt per week, so I just use the remaining yogurt from the previous batch for the next batch. I'm not sure if this will maintain the same blend of bacteria over the long run, though, because I don't know how well my particular set of bacteria get along with each other, out of the advertised 9 active cultures.

Now, time to get to work. Put some water in the bottom of the double boiler, some milk in the top, and place the thermometer in the milk. Then heat the milk to just above 180 degrees Fahrenheit. Stir it now and again so it warms up evenly. Once it reaches that temperature, remove the top of the double boiler from the heat, and allow the milk to cool back down to a temperature between 105-110 degrees Fahrenheit. You can make this happen faster by setting up a cold-water bath. Keep stirring it to maintain an even temperature. Once you reach the target temperature, add in your yogurt starter. The general ratio to use is 1-3 tablespoons per quart. Also, when you are trying to make yogurt, more starter isn't necessarily better - the bacteria won't grow as well if they're too crowded. Mix in your starter thoroughly.

The bacteria in yogurt like to live and grow under some specific conditions - namely, they are most comfy between 100-110 degrees Fahrenheit, and they don't like to be jostled. So, set up your heating pad in a spot where you can leave things undisturbed for ~8 hours, and put it on high. I also think it helps to pre-warm the jars - I use some of the water from the double boiler for this. Once your starter is mixed in, pour the milk into the jars, put the jars in their warm, snuggly environment, and leave them there for a long while. Oh, I also pop a tea cozy over the tops of the jars - you could also wrap a towel around them. Once the long while is up, put the jars in the refrigerator and you have yogurt.

Now, an important question: why make your own yogurt? After all, it takes more time and thought than just buying a carton of yogurt at the store. And what if you screw up? I can think of a couple of reasons why, and have a few ideas for screw-ups. First, for those of us who live and eat by ourselves, a full carton of yogurt might be too much, just as a full gallon of milk might be too much. But take part of that gallon and make the right amount of yogurt, and the problem might be solved. Secondly, sometimes yogurt is expensive and travels from very far away, while milk is somewhat less expensive and comes from nearby. Save some money and some gasoline and make your yogurt from more local milk. Thirdly, yogurt from the store comes in plastic containers. While these containers are quite handy, in my experience they eventually stack up and overflow the cupboards, crashing onto the floor and creating quite a mess. Even better than recycling is PRE-cycling, also known as reducing waste before it happens. Lastly, maybe your favorite type of yogurt is hard-to-find where you live, so making it yourself is a simpler solution.

As for screw-ups, well, if you start growing fungi, you'll just have to toss your milk (and boy am I curious about how that happened). If your yogurt isn't the desired consistency (i.e. too runny), just tell your friends that it's buttermilk and use it accordingly - it should still be acidic enough to substitute for buttermilk in recipes. Also, you can generally still use the culture for your next batch of yogurt. I've also heard of adding in additional milk powder to get yogurt that's more solid, but I haven't tried it. Google that business and come up with your own solution.

One last thing I've wondered about - a lot of websites say to be sure and start your next batch of yogurt within a week of the previous batch. Will this really make a difference?

* A lot of people have developed other methods for keeping their cultures stable and happy at 100 degrees. For instance, if you live in a hot place where temperatures are consistently between 100-110 degrees, you really don't need to use electricity to do nature's work. Other people have told me about using their ovens for the same job, but that would be particular to each person's oven's personality, and I suspect that ovens won't maintain as high a temperature for as long as the heating pad method. So, oven-cultured yogurt may be more runny than heating pad-cultured yogurt. Yet other people have written about using a cooler and hot water baths, to which I say, jolly good for them. All's I know is, the heating pad method seems to work pretty well.