Using plain old Soda Water
Especially when the kids where young I used to store Soda water(Store Bought) and add cordial of different flavours. I did not want my boys to have Coke or Pepsi. I went for the high fruit cordials.
As long as it was cold and fizzy they liked it. I have made Ginger Beer mainly for myself as I made it based on a beer recipe. From memory
1 kg Malt
1 kg Sugar
3 desertspoons dried ginger
a sprinkle of Lager Yeast
I brought the malt Sugar and Ginger to the boil and poured it into the fermentor added 20 litres of water and added a sprinkle of the yeast.
I fermented for two weeks and bottled with a teaspoon of priming sugar.
I never used a secondary in those days, more's the pity.
The result after 3 weeks was excellent. I used Sodium Metabisolphate to remove ginger traces from fermentor.