Why should I use yoghurt starter rather than just subculturing from actual yoghurt?
Subculturing is the process by which you make yoghurt by adding a small amount of already made yoghurt to milk and incubating at the required temperature. This is a popular way of making yoghurt at home, but there are a variety of problems associated with this method. One problem is that over time the bacteria in yoghurt die out, and the older the yoghurt is, the fewer live bacteria that are left to subculture from. Connected to this is the various strains of bacteria die out at different rates, which means that after subculturing a few times the bacteria remaining in the yoghurt often get out of balance. This can cause your yoghurt to be overly runny, or have an abnormally strong flavour. It is much more reliable to add yoghurt culture directly to your milk. You should never subculture ABT or ABY culture if you want to grow probiotics.
