Of course, these fermented foods (pickles, sauerkraut, yogurt, good air-dried charcuterie) are the product of decay and the growth of tiny microorganisms that we, in our modern age, have become afraid of. We pasteurize milk, only to add probiotic bacteria right back into it to sell as part of a new health craze. The bright tang of buttermilk in the old days was a result of raw cream developing a culture of bacteria, then being churned into butter. What was left was buttermilk, and the culture thickened the already low in fat liquid and gave it it's trademark tanginess. These days, the pasteurized milk is skimmed of fat, then a culture is added to it--not true buttermilk in many ways at all.
BUT, we can make all of this stuff at home the old fashioned way ("old fashioned" usually meaning with more heart, soul and, importantly, flavor), and they turn out delicious and interesting. Wanna save money this summer? Get good produce from the farmer's market and pickle it. Or turn it into preserves. Keep it into the winter and have summer veggies and fruit all year round. And if you are someone who can't live without dairy products, like me (or my rotund cat, Akuma), make some yogurt at home.
Now, as a rule, when I buy yogurt, I always get the good, thick Greek yogurt. Fage is a good brand, and one made somewhere in Illinois (whose name I forget) can usually be found in the smaller markets as well. This stuff isn't made for scarfing down on a lunch break with a box of Teddy Grahams and a Capri Sun--this something to dollop onto fresh fruit with a bit of honey or spread on toast. And you can make this thick yogurt at home as well. But I'm gonna be honest here--the people who make Greek yogurt can, at this point in my yogurt making career, do it much better than me, so I am going to stick to my very own style of "regular" yogurt--that is, much less thick, but every bit as tangy.
I started a batch today, and it amazes me how this is something that is so quick and easy to do--one of those things that takes hours of waiting time and just a few minutes of actual active time. That's because all the real work is done by the bacteria we add to the milk to make it all happen. Inspired by an article in the New York Times by the venerable Harold McGee, author of On Food and Cooking (a must have if you want to delve deep into the science of food), I charged off to the store to get the ingredients to make yogurt.
The trip home was much easier than one might think, because all I had to carry was milk and yogurt. I know, weird--buying yogurt to make yogurt. But as McGee put it in his article, if you aren't lucky enough to be given a yogurt culture starter by a friend, or resourceful enough to find a place that sells the culture in raw form, your best bet is to buy some yogurt with live cultures and use that as a starter. And the cheaper the better. My thinking is that fresh bacteria is added to each batch of the big industrial brands, as opposed to the smaller, more "boutique" yogurts being cultivated with more interesting but perhaps less potent strains. And sure, the big brands are full of stabilizers and the like, but for the small amount used, these get diluted over time (after all, we can use our new batch of yogurt to start the next one). This in mind, I still decided to buy organic yogurt to go with my organic milk (milk is something I don't compromise on too much, usually buying small farm and organic).
The equipment is simple. The process is simpler. I remember, as a boy, seeing a yogurt machine around the house--as I recall it was a tray of eight or so little cups, into which milk and culture would go and be covered, the whole contraption then plugged in and incubated for a time to convert the milk into yogurt. Thus, until recently, I always viewed yogurt as a big pain to make--lots of specialized equipment and all that. But McGee's article opened my eyes--all I needed was a pan to heat milk and a container to keep the yogurt in. An optional thermometer helps, but isn't absolutely necessary, as I'm sure the ancient Greeks didn't have instant-read thermometers.
About a quart of milk (whole milk, by the way; I'm still not sure why skim milk exists) is heated to 180°F - 190°F, or just about where the milk is steaming and starting to bubble. This denatures the whey proteins called lactoglobulins, which then cluster on the surfaces of the casein particles (proteins which form the curds, or solids, in milk products, as opposed to the whey, or liquids). This prevents the casein particles from clustering together, allowing them to bond to each other in only a few spots, creating a fine matrix of chains that works much better at retaining liquids. Think of a sheet of ice covering a body of water as opposed to several icebergs floating on the same water. (Huge thanks to McGee and On Food and Cooking for making the information in this paragraph understandable.)
Then, the milk is allowed to cool to roughly 120°F, which is just very warm to the touch. Any chef who has been through the nightmare of an annual health inspection can tell you that in order to prevent the growth of bacteria, temperatures must be below 40°F or above 140°F. And if this chef likes delicious food, they can also tell you that sometimes, keeping food between 40°F and 140°F is crucial to development of certain beneficial bacterias as well. So, seeing how I'm not in a restaurant anymore, and seeing how the health department can't shut down Food on the Dole (though something tells me that the Daley Empire could find a way), I will say that it is crucial to keep the temperature of the milk/yogurt around 100°F to 120°F for the duration of the process. Much hotter, and the bacteria will die; much cooler and it would take the bacteria forever to get the job done of reproducing and turning the milk into yogurt. Basically, you want to recreate a really hot day on Clark Street after a Cubs game. But with more savory specimens involved.
Once the milk is cooled to the desired 120°F, we take a cup or so of it out and stir that with a couple of tablespoons of our plain yogurt, full of live and active cultures. We mix this all back into the rest of the milk and pour it all into an appropriately sized container, cover loosely and put in a warm spot to maintain the temperature. If it's cool in your kitchen, wrap the container in several kitchen towels and put it in the oven (which hasn't been turned on, of course). Me, I ran my microwave with a couple small saucers (to retain heat) in it for a few minutes, then put the wrapped container inside and closed the door. The residual heat left inside the microwave ensured the warmth of the mixture, and I've gotta say, it worked really well. Now I have a second use for my microwave (the first being melting butter).
The mixture stays inside for at least the health department approved maximum 4 hours (though I found leaving it for about 12 hours or even overnight works even better), then it gets put in the fridge to cool and set a bit more. And what comes out in the morning is like magic. Smooth, creamy, rich and tart as can be. Delicious with fruit, with honey, in pancakes and waffles, drizzled on steel cut oats. And way cheaper than buying yogurt. Plus, a bit of this batch can be saved and put into the next as a starter, or even given to a friend to start their family of yogurt. And it's full of good bacteria for the digestive system. All the more reason for that next ham sandwich at The Hop Leaf--lactobacillus delbrueckii subspecies bulgaricus has gotta eat too, hasn't it?