The Art of Making Yogurt
Sara D. Roos
Los Angeles CA USA
From NEW BEGINNINGS, Vol. 25 No. 4, 2008, pp. 40-41
Most of us are familiar with "antibiotics," but suddenly there's this new term out there: "probiotics." As the prefix suggests, the first zaps ("anti") bugs or life ("biota"), the other supports them ("pro"). We all have a whole lot of bugs inside our gut naturally; this "flora" is important to processing and digesting food properly. When something wipes out that normal flora (e.g., antibiotics), or its constituents are for some other reason not optimal (e.g., illness, poor diet), it's nice to know how to help re-grow a proper mixture of the biota critical for our optimal health.
This, it turns out, is what yogurt and other cultured foods are all about. Eating yogurt is not new of course; it's been part of the rhythm of life in many cultures since ancient times. What is new is our understanding of how these cultures (the bug kind, not the social human kind!) help our bodies: they recalibrate the spectrum of natural flora that inhabits the digestive tract.
In keeping with these ancient rhythms, making yogurt can even be a soothing household ritual. It's a healthy, cost-effective way to improve your whole family's diet disguised as a fun activity as well.
I've been making yogurt for years and it is an integral part of my and my family's "lifestyle." Hence it is difficult to convey a recipe because the devil is in so many details! At root the task is simply to provide a hospitable milk-environment for bacteria to grow, or be cultured. The goal is to control that growth so that fermentation (as opposed to a different chemical process) occurs. Lactic acid is a waste product of fermentation and its presence acidifies the environment. Under these conditions the proteins of the milk get transformed into that nice thick-creamy texture we all love! But it is the cultured bloom of flora we eat at the same time that is so healthful. Accordingly I will describe the process of making yogurt in its various stages.
Pour a half-gallon of milk (non-fat or organic is fine -- I have not tried soy or rice but would welcome anyone's feedback about whether this works, too!) into a heavy, metal sauce pot. On medium-low heat, stir the milk every five minutes or so to prevent it from sticking on the bottom of the pan. It may be necessary to use some force with your spatula, though this depends on the pot you're using.
Set a timer and heat the milk for a little over an hour, just below the boiling stage (the milk will get little bubbles along the edges but not big ones in the middle). When 10 to 20 percent of the milk is gone (one inch from my very full three-quart sauce pot), shut off the heat. Remember to keep stirring until the milk is cool enough not to stick (about another 15 minutes). This stage can be shortened, but the longer you keep milk at this high temperature the thicker the yogurt will become (because you assist in the breaking down, or "denaturing" of the milk proteins).
Let the milk cool for about an hour at room temperature, depending on the temperature of your kitchen. The goal is to have warm milk, but not so hot that it will kill the bugs you will be adding to (inoculating) it, but warm enough to encourage bug reproduction. I compare the cooled milk's temperature with my own body temperature by running it over my wrist. When the milk dribbling over my wrist is unnoticeable, it's the right temperature. If you use this method, be sure to wash your wrist well!
After cooling the milk to room temperature, transfer it from the saucepan into the container that you will be storing the yogurt in. This container will need to remain warm for some time. I use a heating pad and cover it with two small thick towels at right angles to one another and make an insulated, heated cocoon around the yogurt container. Don't turn on the heating pad until you've inoculated the milk (next stage); just prepare the environment for now. Glass and plastic containers are fine for storing the yogurt -- old yogurt containers work, too.
Place a heaping teaspoonful of your favorite-tasting (plain) yogurt in a little cup. The yogurt you purchase should contain "live culture," and preferably no fillers or thickeners like pectin, guar gum, or carageenan. Manufacturers use different combinations of various bacteria, so store-bought yogurts all taste slightly different. Experiment to find which brands you enjoy the most.
Spoon a bit of the warm milk into this cup and mix the yogurt with the milk until it is a slurry. Gently swirl the warm milk that is to be cultured, which is now residing in its insulating environment (previous stage), and pour the yogurt slurry so it streams into this swirl. This mixes the yogurt into your warm milk without breaking apart the slurry too greatly.
Now the culture must sit, undisturbed and warm, for three to eight hours. The trick is to keep the culture warm -- but not too warm -- for all this while, preferably for less rather than more time. You can cover the milk container slightly, but not completely; fermentation produces gas! I wrap the covers and then the heating pad around my container and set it to low. The faster you encourage the culture to proceed, the better-tasting it will be. But if it becomes too hot, the culture will die. If it takes too long it may be sharper in flavor or waterier.
Refrigerate when thick. Be sure to save a teaspoonful from this batch to reinoculate your next batch of homemade yogurt! It is not necessary to continue to purchase yogurt after the first time you make your own yogurt, but note that sometimes a culture can get "tired" and you may wish to periodically start afresh.
There is huge leeway for success when making yogurt. I have forgotten a culture and allowed it to grow cold for 12 hours, re-set the heating pad (without even reheating it to near-boiling), and wound up with a yummy culture. Sometimes it takes my culture three hours to thicken, sometimes 10 -- and I think I'm doing just the same thing every time! The variables involved are myriad and I sure can't track them all! Experimentation is very much in play here.
My children love to bring homemade yogurt to school along with a little bag of cereal or granola, and sometimes raisins and a small container of fruit jam or honey. It's a kit that they love to mix up, and I believe a part of their enthusiasm involves the ritual of making this household staple.
As a "professional mother," it feels like it's part of the job to provide my children with food that fortifies their bodily functions. One of my children suffers from Crohn's disease, an autoimmune digestive disorder, which many find is mitigated somewhat by taking yogurt. Enabling a taste for healthy food feels like the right thing for me to do for my family.