Conversation:

This level of sugar will produce a lot of gas. This may (?)be safe in true champagne bottles which are specially designed to take the presure.

However most glass bottles are NOT strong enough and you are making yourself a stock of glass hand-grenades , most likely to explode exactly when you pick the up and possible knock them on something.

A safer approach is to ferment in two stages which allows you to vary the alchol level as well.

ferment for about 3weeks in fermenting vessel fitted with and airlock.

Once activity has died down almost to a stop add a controlled ammount of sugar and put in sealed bottles. The final sugar will add the fizz.

Beer requires a rounded tsp of sugar per beer bottle. If you have stronger cider bottles, plastic bottles or Grolsch bottles double dose that to get more of a champagne level of fizz.

i got grolch type bottles and a free recipie sheet for elderflower champagne (by asking)from home brew on line in york

Let us know how it turns out!