Lol, if only there was a way to get the nozzle from the sodastream into the water... (go 80's).
just buy a packet of yeast at the grocer. Mix it with 2 cups of sugar in a 2 litre bottle with an air tube through the cap.
I make the hole smaller than the tube, then put the end of the tube through, jam a 2 way connector into the tube end and force it back to the hole in the cap, so the inner connector is pressing the tube tight against the lid.
Leave about 3 inches open in the top when filling with mildly warm water.
I mean like it must hardly feel warmer than your hand... Using the whole packet of yeast should give a strong, if short production of co2.
Cape Town, South Africa.
Hi. I'm back.