Cheese is a living, breathing thing, and results can be as variable as the environment in which it is prepared and the cultures that are used. Commercially-available starter cultures are readily available, and will give you more consistent results while you are perfecting your techniques of making and aging cheese.
If you like, you can experiment with your cheeses by making your own mother culture. Usually the amount of prepared culture required is replaced with 2 tablespoons of your own mother culture. Results will vary, but you will find that you will have some lovely variations in your cheeses. The following recipe can be used in any cheese recipes.
Culturing your milk:
Strain 1 cup of fresh, raw milk through a fine cloth, to remove any contaminants, and place it in a covered container. Leave it in a warm place (20C is ideal) to clabber until it becomes thick and tangy, similar to drinking yoghurt. This will usually take 24-48 hours, though it sometimes takes longer.
From the first clabbering, take 1/4 cup and to it add 1 cup fresh milk, cover, shake to combine, and let sit to clabber again. Repeat this step until the mixture clabbers reliably in 24 hours.
To make your cultured buttermilk, or mother culture, take 200 mls of the clabbered milk mixture, place in a 1 liter jar and fill with fresh milk. Cover, shake and allow to clabber once more. Taste it at this final stage. It should be tangy, not bitter. Then refrigerate or freeze. You can freeze it in an ice cube tray and use it in your cheese making. It will keep for about 3 months in the freezer. You can also use clabbered milk in baking, which really adds to the lightness of your cakes and scones.