This is how the last stages can also be done:

Take a jug of 1 gallon of water and add enough "plant" to make the mix taste "gingery". Then, you add sugar to the jug (the following is approximate)

2 lbs of sugar + 1 gallon of water = 12%-14% alcohol (very strong)

1 lb of sugar + 1 gallon of water = 6%-7% alcohol (still pretty strong)

1/2 lb of sugar + 1 gallon of water = 3% alcohol (like a low alcohol beer - use this).

Keep the cap on loose until the bubbles stop.

Then you filter the swill (you need to filter it, or it will be gross) and add 1/4 tsp sugar and screw the cap on tight and let sit under the kitchen sink for 2 weeks (this will carbonate it).

The result will NOT be sweet, but you can keep it on a shelf for 6 months or more.

If you want it sweet, add 2 Tbsp sugar instead of 1/4 tsp, and ferment until the bottles are firm (it may only take a few hours!!!)

Then put the bottles in the fridge at 40 deg F or less (this stops the yeast).

If you let the ferment happen and the bottles get too firm, they will blow up. You need to drink the juice within a few weeks, as the ferment will proceed slowly in the fridge and eventually blow up.