We have been making our own yogurt for a little while now with consistently good results.
Here is the recipe I use, the children really love it with a teaspoon of honey swirled though it.
I use the Paris Creek bio-dynamic organic yogurt as a starter because it is the only commercial yogurt I have found that does not have any thickeners in it, it's just milk and cultures.
You can also get starter sachets from the supermarket, but I don't know how to do it that way.
We use raw milk from our neighbours jersey cow. I skim a cup of cream off and then use three cups of un-skimmed milk mixed in with the cream. In the city you could try the Parmalat organic milk, it is really creamy.
I make the yogurt in a kefir pot (a ceramic jar with a lid), this is what they use in India, but you can use anything.
For incubation I use a little Kenwood yogurt incubator to put the pot on, it is a little platform that heats up to the exact temperature required to make yogurt.
But you can also use a hot water system, a sunny window, a thermos, or the pilot light in your gas oven for incubation. It is also possible to use an electric oven by turning it on full boar for 5 minutes and then turning it off- I haven't done it this way, but it may be worth a shot if you are really keen and don' have any other alternatives.
So, here is what you need to do:
IF YOU DO NOT HAVE A FOOD THERMOMETER: heat your creamy milk in a thick bottomed pan, or a double boiler, on the stove to the point just before boiling. Let it simmer for 10 minutes. Remove from heat and allow to cool down to the point where it is between hot and warm.I call this "high fever" point, because it is the point just above a normal body temp (36-37 degrees) - between 39 and 41 degrees Celsius.
IF YOU DO HAVE A FOOD THERMOMETER: heat your milk in a thick bottomed pan, or a double boiler, to the point just before boiling. Allow it to cool to between 39 and 41 degrees Celsius.
Add .5 of a cup of culture ,stirring gently. Now the yogurt needs to be incubated. It must not fall bellow 38 degrees. The longer you incubate it the tarter the taste. I wrap the kafer pot in two or three old cloth nappies and put it on the incubator. It takes about 4 hours.
Once it is done immediatley put the yogurt in the fridge.
Homemade yogurt is runny compared to commercial yogurt, and it has lumps in it. If you really want thick yogurt you can use gelatine, just disolve it in at the heating stage. You can also add powdered skim milk which is what they do in a lot of commerically made yogurts.
For creamier yogurt you can add pure cream.
You can add honey at the heating stage too.
I use use this yogurt in bread making as well.
Save .5 of a cup of yogurt as starter for your next batch.
It may to a little while to perfect but it is worth it for delicious home made yogurt. Good luck!