Go for a walk and pick some nice big elderflower sprigs.
Bring 2l water to the boil and dissolve the sugar in it. Leave to cool down.
Clean and wash the elderflowers sprigs from any insects, dead flowers and cobwebs.
Add the cooled down sugar syrup to a large fermenting bucket (10 litres). Add the remaining water, lemons, yeast and elderflowers. Stir well and cover with a lid or muslin cloth.
Leave to ferment at room temperature for 4-5 days. Stir every day.
2nd stage of fermentation
After the 4-5 days discard the elderflower sprigs and lemons. Pass the liquid through a muslin cloth and then decant into used but cleaned sparkling wine bottles. Push a plastic sparkling wine cork into the bottle and secure with a wire cage.
During this stage carbon dioxide will build up and can cause the bottles to explode hence the securing of the corks with wire cage. Alternatively, you can use plastic bottles.
The second stage takes about 2-4 days. To stop the fermentation process put the bottles in the fridge.
Enjoy chilled.
Be careful when opening the bottles as they are under pressure.