Abbie Hoffman wrote a wonderful work known as "Steal This Book" in 1970, and advocated stealing from the "Pig Empire" (in fact insisting that it was immoral not to). Although the book is somewhat dated, and mostly reflects the YIP zeitgeist of the time - it informs this post.
Today is yoghurt*, which is one of my favorite, long-standing processes that I have been cultivating for years. The reason the post is titled "Steal This Culture" has to do with the fact that although you can insist on being a purist and buying your own fancy starter cultures - you can steal some cultures from the Pig Empire!
There is a certain company that has some very nice cultures in their yoghurt, their name starts with a "d". Just grab (or steal if you really want to take from the Pig Empire) a small cup of said plain**, at least 2% fat, yoghurt. Check out the back and you'll see that you've got some live & active cultures on your hands. Now you just have to keep them going.
- 1 cup of plain, at least 2% fat yoghurt
- 1 quart of Whole Milk (Raw, P & H, whatever is fine)***
- A nice glass jar with a top
Start yourself out with a whiskey sour or Campari on the rocks. This will steady your nerves, especially if you've never stolen anything before. Also, take your cup of yoghurt out of the fridge now.
Now, get a saucepan, or pot, or whatever you want to use and dump your milk in. Start some gentle heat underneath. Don't be too violent with the heat, you'll have a hellish time scrubbing burnt milk off the bottom of your pot.
Here is where a nice thermometer is very helpful, as you have to bring your milk up to 82º C / 180º F and not much hotter. Take this advice from me, too hot and you will clobber your milk. No yoghurt for you. If you would rather not get a thermometer, a good indicator is when you just begin to see some nice steam coming off the milk, and it looks slightly frothy around the edges (like just before a storm at sea). It should not be boiling.
When your milk arrives at this point, turn off the heat and let it sit and ponder that temperature for about 10 minutes. You may have to give it some light heat halfway through so that things don't creep too low.
After your milk has contemplated its near-boil, cool it as rapidly as possible. This aspect can be completed in a number of different ways, choose whatever works for you - ice bath, water in a double boiler, vigorous stirring, etc. No hard and fast rule here, just try and bring it to 38º C / 100º F (it should feel like a warm bath, for those without thermometers) as fast as you can.
Once it arrives, you are ready to abscond with some cultures. Scoop a nice amount of yoghurt into a small bowl, and add a bit of the now warm milk and stir gently. As with the yeast, your yoghurt is alive. When you have been outdoors in the winter months for a long period of time, your extremities often grow very cold. Upon entering your home again, you might run them under some warm water, or take a nice bath. I find that when I do this, the water will initially feel unbearably hot on those extremities. I usually grow accustomed soon. Your yoghurt culture is the same way. Let it grow accustomed to its environment.
Pour the now soupy mixture back into the milk and stir. Now decant into your nice jar and cap. Your final act is to now cultivate those stolen cultures, and to do so you need some warmth. People have devised some of the most elaborate, ridiculous setups to warm yoghurt; ignore them all. You can do a few simple things : (A) I have an oven with a pilot light, sitting the jar inside keeps it plenty warm. (B) If you have a crock pot/slow cooker, fill it halfway with some water, put it on low, and sit the jar in the water. (C) Put your oven on the lowest temperature possible for about 10 minutes, open the door for a few seconds, put the jar in and don't open it again (feel free to comment with your own methods).
You just need to keep it in the vicinity of 38º C / 100º F. Keep it in this vicinity for at least 4 hours, more if you would like it very sour. Take it out of its warmth, and place it in the fridge to firm up a bit and enjoy your stolen yoghurt****. The best thing is that if you don't let it sit for too long (no more than 1.5 weeks), you can now just use your stolen cultures to make more (just don't eat it all). No need to buy a new cup every time!
* Spell yoghurt with a nice 'gh' in the middle. The word is from Turkish, and has a nice voiced velar fricative in the middle, best represented with 'gh' not 'g.'
** Maybe self-explanatory, but using any other flavor will probably result in very odd-tasting yoghurt. Also, don't use 0% or 1% fat yoghurt, it has a number of fixatives so that it isn't like soup.
*** Whole-fat milk makes wonderful yoghurt that does not require any strange fixatives to thicken it. Allow yourself this indulgence. Also, the cultures in yoghurt eat all the lactose (hence its sour nature), so give some a small try if you happen to be sensitive to lactose, you might be able to handle it.
**** If you like the ultra-thickness of Greek-style yoghurt, just dump your yoghurt into a cheesecloth, or really any other finely-meshed cloth (I once used an old T-shirt) and let it sit for a few hours. This yoghurt will likely be a bit runnier than you may be used to. You can always add a shake of unflavored gelatin prior to jarring if you find yourself bothered by this feature.