What is yoghurt?
Yoghurt is the result of fermenting milk using bacteria (Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus bacteria. Lactobacillus acidophilus, bifidobacteria and Lactobacillus casei are also used for some yoghurts). The bacteria convert the lactose in milk to lactic acid, making it tangy, and also act on the proteins in milk, which causes it to thicken.
Ingredients for making yoghurt
All you need is some form of milk (powdered or liquid) and the starter cultures (either freeze dried or sub-cultured from another batch of yoghurt).
Forms of milk that can be used
- Powdered milk - this is the cheapest option, but there are some doubts about the effect of the drying process on the structure of the cholesterol in the milk, particularly full cream milk powder, so its probably not the healthiest option (I found one cup of powdered milk per litre of water made lovely thick yoghurt though).
- Pasteurised milk - if you don't have a cow, this is the next best option, go for organic and unhomoginised if you can (I haven't tried store-bought pasteurised milk yet though!).
- Raw milk - I have tried to use raw milk, and can't get it right, apparently is also depends on the cow's diet. I have given up and started pasteurising my fresh raw milk before I make yoghurt. (see update of raw milk yoghurt here)
- Freeze-dried - can be ordered from the internet and kept in the freezer. A few grains are used to inoculate each batch of yoghurt.
- Sub-culture - a spoonful of yoghurt from another batch (or from bought yoghurt) can be used to inoculate a new batch. If everything is kept clean this can last for ages, but occasionally it can become contaminated and a new culture is required.
A few affiliate links to get you started with yoghurt:
OzFarmer - Yoghurt making kit
OzFarmer - Propiotic yoghurt culture
Biome - Yoghurt kit
You might also be interested in my series on getting started with homestead dairy
Interview with Mark and Kate from Purple Pear Permaculture
Interview with Kim from the Little Black Cow
Interview with Rose Petal
Interview with Marie from Go Milk the Cow
Interview with Ohio Farmgirl