You need is to peel and grate ginger, and cut the zest from the lemon. Mix zest, ginger and sugar, and pour them with the boiling water (3,5 liters). Dissolve the yeast in a glass of warm water, and pour it into the ginger water when it is cooled. Put the squeezed lemon juice into the ginger water. Stir the drink and leave it to infuse for 12-24 hours in the room. Filtrate the drink and pour into the bottles, close them and put it into refrigerator for two days. Drink it chilled.