- In a sterile 2 quart jar, blend together the yeast, 2 teaspoons of castor sugar, and 2 teaspoons of ground ginger. Stir in the cold water until well blended. Cover with a clean cheesecloth, and let sit in a convenient corner at room temperature where it will be out of the way for the next seven days.
- Every morning for the next seven days, feed the yeast mixture by stirring in 1 teaspoon of castor sugar, and 1 teaspoon of ground ginger.
- On the eighth day, give the mixture a good stir, then strain it through a clean tea towel into a large new plastic bucket, bin, or glass carbuoy. Wring all of the liquid out of the cloth, and set aside. You will be dealing with this later.
- Dissolve the white sugar in 5 cups of boiling water by stirring vigorously. Pour the cold water into the bucket with the ginger juice, then stir in the sugar syrup and lemon juice.
- Siphon the mixture into sterile screw top bottles, filling to within 2 inches of the top. Old cleaned out soda bottles will do. Screw on the tops tightly. Store the bottles of ginger beer in a cool dark place where they can remain undisturbed for 7 days. Be very careful upon opening as the beer is very fizzy.
- Go back to the cloth now. The residue looks disgusting! However, lay the towel out flat with the disgusting side up. Use a knife to scrape the stuff to the center, then divide in half, and place each half into a separate sterile jar. Top each jar with 2 cups of cold water, and you are ready to go again. Twice! Begin with step 2 for subsequent batches. Unless you are very thirsty, I suggest you give one of them away.