Do you mean without any dry or liquid malt?
Don't think it would be a good idea - Coopers BE1 is a mix (50/50 I
think) of maltodextrin and dextrose. Dextrose is sugar made from corn,
will ferment completely and normally used to boost the alcohol level.
Maltodextrin is not fermentable by yeast and is used in beer to give it
more body and sweetness.
So what you're considering is brewing without fermenting any barley
malt so which would it still be beer?
Coopers BE2 on the other has maltodextrin, dextrose and light dry malt
but it's probably still not enough malt by itself.
T.
[note that maltose is a fermentable sugar and not the same as maltodextrin]