There are many reasons why a person might want to make his own yogurt — to save money, and to avoid high fructose corn syrup and artificial flavorings and artificial colorings that most commercial yogurt has. There are many ways of making your own yogurt; and I remember my mom had a yogurt maker when I was a kid. But I don’t remember her ever actually making yogurt — it was just a brightly colored something that was stuck in the back of the cabinets out of the way. I’m assuming she bought it when yogurt was a “brand new” fad back in the 70s (although people have been making yogurt for centuries if not millenia), to make her own. But it didn’t work right. (Does anybody else remember those? It had a small flat base that I guess was the warmer, and maybe 4 different-colored jars that sealed with metal doohickeys. Enough of the trip down memory lane. Now back to your regular programming!)

There are still lots of formulas and gadgets to make your own yogurt (you can google or ebay for them if you want), but here’s the way I make my yogurt, and I’ve never had a batch to fail. This recipe is from The Tightwad Gazette, and I would highly recommend this book to anyone for all of the frugal tips, and just the mindset I get when I read it. What I’ve got here makes a quart, but I’ve made as much as a gallon at one time.

Yogurt

2 Tbsp. starter yogurt, room temperature
1 quart milk + ½ c. milk powder

Combine the milk and milk powder in a large saucepan. Heat to 180º and cool to 115º. [Update -- if you use only powdered milk in this recipe (as opposed to milk bought from the store in jugs, or previously-mixed powdered milk), you will not need to heat to 180 and cool to 115 -- you only have to heat it to 115. You heat it to the higher temperature to kill bacteria in liquid milk, but milk powder doesn't have any bacteria.] Add a small amount of this warm milk to the starter, whisk, and add this mixture to the saucepan of milk, and whisk again. Pour into a quart jar, screw on a lid, place on a heated pad set on “low,” cover with a towel, and cover that with a large soup pot. Incubate for 8 hours or overnight.

You can make larger batches, but to efficiently chain-yogurt and to avoid old, tart-tasting yogurt, don’t make more than a 5-day supply. All failed and too-tart yogurt can still be used to make popsicles and in cooking. You can make “yogurt cheese” by lining a colander with cloth, plopping in the yogurt, and draining (in fridge) overnight. (Stir in a pinch of salt before draining to improve the flavor.) The liquid is whey which is very nutritious and can be used as milk in muffins and other baked goods.

A few questions one might ask:

• what is “starter yogurt”? It’s simply store-bought yogurt. Buy the plain yogurt (unflavored, unsweetened; although I think I’ve made it with vanilla yogurt before), which I’ve only found in the quart-sized containers. To save the most money, use what you need and freeze the rest in an ice cube tray or muffin tin, in 2-Tablespoon increments; then when you need to make more yogurt, thaw a portion of it for the next batch. Make sure that the yogurt you get has live, active cultures in it! If the yogurt isn’t “alive” then your home-made yogurt will not set up.
• what is “milk powder”? Powdered milk, which should be available at most grocery stores in the baking section (or ask an employee where it is). I almost never buy regular milk, because we don’t use much milk except in baking, and a gallon will go bad (and at the price of milk these days, I hate to waste money like that!). So when I make yogurt, I just make up a quart or two of powdered milk and add in more powdered milk. I’ve also used regular store-bought milk when I had it, and added in the powdered milk, and it works just fine too. If you’re calorie-conscious, powdered milk is fat-free and lower in calories than 2% milk (which is what we use) or whole milk; so that makes this even better!
• what gadgets do I need? Just a cooking thermometer (maybe cost you a couple of bucks, if you don’t already have one) and a heating pad (which most people already have; and if you don’t, get one — it’ll come in handy on those cold nights).
• can I flavor it or make it sweet? The one batch of yogurt that I’ve had to fail (which I don’t count, because I deviated from the recipe) was when I tried to pre-sweeten and pre-flavor the yogurt. It just didn’t set up at all. I’m wondering if the sugar or vanilla killed the “live active cultures” when it was setting up. So, sure, you can sweeten it and flavor it — just do it after you’ve made it. (If anybody knows of a way to sweeten and/or flavor it before-hand, please let me know!)
• why do I have to heat it up to 180 degrees? I’m not sure, but I think it scalds the milk and kills anything that might be in there (like pasteurization), or perhaps it changes the nature of the milk so that it more easily turns into yogurt.
• why can’t I just add the yogurt to the milk while I’m heating it up? Because heating it that high will kill the cultures, and you’ll just end up with a quart of warm milk in the morning.
• why do I add a little of the warm milk to the yogurt and then put it back in the pan? why can’t I just put the yogurt into the pan of milk to start with? Because the yogurt is room temperature, and the milk in the pan is quite a bit warmer, if you put the yogurt into the pan of milk, you would shock it and kill it. Adding a little of the warm milk to the yogurt “tempers” the yogurt, and slightly warms it up enough so that it won’t kill it when it’s added to the much warmer milk.
• do you have any other tips? Yeah — watch the milk while you’re heating it up, and stir it occasionally so it doesn’t scorch or stick to the bottom of the pot. You can set up a double-boiler or “water bath” (a large pot is partially filled with water and the smaller pot with the milk rests inside with the bottom touching or below the water). I’ve never done this, but I have scorched the milk before.
• what is “chain-yogurting”? It’s using your home-made yogurt as starter for future batches of yogurt. The author of The Tightwad Gazette said that she “chain-yogurted” up to 5 times, before the yogurt got too tart or didn’t set up well. The “nerd” part of me that likes numbers wonders how many batches of yogurt you could get from the original store-bought quart if you only used it as starter; and then used all of the next four chain-yogurted batches as starter, and only ate the 5th batch in its entirety. Yeah, I’m weird that way. For what it’s worth, I can’t remember the last time I bought yogurt, and I still have probably 6 ice-cubes’ worth of it in my chest freezer. This last batch I made, I froze enough starter for 12 quarts of yogurt.

If you have any more questions, or more tips or insights, or if you just wanna say something, don’t hesitate to leave a comment!