I've been making yogurt for about a year and a half. I first read about the process on a blog called Organic & Thrifty. (If you're interested, it's some interesting reading about real food and how to do it thriftily... is that a word?)
Basically, you put milk in a quart glass jar, then put the jar on a dishtowel in a pot of water. Heat the milk to 180 degrees, then take it off the heat and cool to 110 degrees, then add your yogurt starter.
That's a good way to do one quart at a time. We keep the same basic concept, but do four quarts at a time. If I'm already making it, I might as well make it in mass!
I learned from "Wild Fermentation" by S. Katz the reason for only needing to add one tablespoon of starter yogurt. Adding too much creates a watery product because the bacteria are too crowded. Somewhere in the last year, I started adding a half cup of starter culture, I can't remember why. I suppose I thought more would be better, but not so!
For making a gallon at a time
- 4 sterilized glass jars and lids
- a gallon of milk (I use raw)
- some starter yogurt, either from a previous batch or purchased from store, I use whole milk yogurt by Stonyfield Organic
- big pot to accommodate 4 jars at once
- Pour milk into jars, and stick thermometer into one.
- Fill big pot with water and stick jars inside water. I have a big pot with a strainer insert, so I put my jars in the insert and it goes into the bigger pot. It keeps the glass jars from sitting directly on the heat, which could cause them to crack. If you don't have a set-up like this, you could just put a thick cloth on the bottom to set the jars on.
- Heat milk to 180 degrees. This kills competing bacteria, so when you add your starter yogurt, it won't have to fight with the naturally occurring bacteria in the raw milk, and gives better results.**
- Take off heat, and let cool to 110 degrees. Then add one tablespoon per quart of starter yogurt.
- Screw lids tightly onto jars, then put into cooler, surrounded by water from the heating up process. You can also put the quart jars into the oven with the pilot light turned on. In my oven, it keeps the temperature between 80-85 degrees. Let sit undisturbed for at least 8 hours, but can be left up to 12 hours. According to S. Katz, a longer fermentation period can possibly make yogurt digestible for the lactose-intolerant person.
- Store your yogurt in the fridge. It will get more sour the longer it is stored. And don't forget to save some yogurt for your next batch!
**I made a quart of experimental yogurt this time. I followed the quick raw milk recipe on this site, except I put it into the oven with the pilot light on instead of into a yogurt maker. I warmed up the milk to only 80 degrees, then added a tablespoon of starter yogurt.
Last night I did a taste comparison. The ones heated to 180 degrees tasted like yogurt. The one heated to 80 degrees tasted more like kefir--a more tangy sour taste--but with a yogurt consistency. I guess it depends on how sour you like your yogurt. More enzymes are kept intact with less heating. The website says that you could just heat the milk to 110 degrees to keep more enzymes intact, but still get more of a yogurt taste, I'd guess.
I am still getting some extra whey on the top of my yogurt, but no problem! That can be strained off and used to soak grains.
Plain yogurt can be sweetened any way you wish. Sometimes I'll just cut up a banana in it, use some maple syrup, or mix in some applesauce with some nutritional yeast and bee pollen. Or use for smoothies, with some frozen or fresh fruit! The possibilities are endless. Or sometimes I'll feed it plain to my toddler. He loves it sour!