I've been making non-alcoholic ginger beer for the past couple of months. Only making batches of 2 litres but experimenting with the recipe. I bottled the ninth batch yesterday and judging by the eighth I opened during the week, I have got it just about right now.
What is in the jar will be the basis of the tenth batch to be bottled in another 9 days. It's the original yeast mix just replenished after each batch with more ginger and sugar added each day. It is possible to ferment to an alcoholic result, so maybe I'll look into that sometime.