It seems easy to do, all I have to do is to have things prepared especially the drink that is to be fermented using the starter that is called a "ginger bug" which just so easy to do.
All we have to do is to grate some two tablespoons of ginger with skin on and washed and then we add two tablespoons of sugar in it plus two tablespoons of water in a clean vessel like a jar.
Then after a day we repeat the process and after five consecutive days of doing that we would see foaming and bubbling going around the ginger. That is the yeast or bacteria eating the sugars which is the fermentation of ginger+sugar.
Source
It now has the colony of good bacteria that now can be used for what drink we would like to ferment. So we just have to have some vessels to use for that purpose but used soda bottles as some say is okay. Now to prepare the drinks that we would like to ferment is up to us but it has to have the basic ingredients like water of course (not chlorinated or tap) but purified, sugar to taste, ginger and tea or other fruits like lemon, orange, or lime and its juices.
We bring those ingredients to boil except the juices of the citrus fruits which should be added after the solution has cooled off. After the cooling we now can add the strained ginger bug to the strained solution and then we can now put it to the jars and bottles with a tight lid.
Now we have to put it in a place that is not too cold but in room temperature for about two to four days so that the fermentation process would take place faster. Then we can now refrigerate it so that we can enjoy it later.
What is the purpose of drinking fermented ginger bug/beer?
Ginger bug or ginger beer has some good bacteria that would help us digest and assimilate or foods. It also helps to fight bad bacteria in our guts so that it would be healthy and resistant to infection. Good to drink for people that is under an antibiotic therapy.