SodaStream SOURCE Manuel D'utilisation page 12

Bottle may not be properly attached. Allow the Soda Maker to finish the carbonation
process and then you can detach the bottle and reconnect it, following the
instructions in the Make Sparkling Water section.
It is normal to hear a small amount of gas escape at the end of the carbonating
process.
WANT TO RE-CARBONATE A DRINK THAT WAS ALREADY
CARBONATED:
WARNING: FOR YOUR SAFETY, NEVER carbonate again after adding the flavor.
You may recarbonate only water, as explained in the "Making Sparkling Water"
section.
WARNING: DO NOT REMOVE THE CARBONATOR OR THE BOTTLE. LEAVE THE
SODA MAKER IN AN UPRIGHT POSITION. DO NOT TOUCH IT UNTIL YOU NO LONGER
HEAR GAS ESCAPING. When the Soda Maker is no longer releasing gas, remove the
carbonating bottle, and contact your local SodaStream Customer Service Center.
YOU HEAR THE SOUND OF LEAKING GAS AFTER INSTALLING A
NEW CARBONATOR INTO THE SODA MAKER:
SMALL PIECES OF ICE APPEAR IN THE WATER DURING
CARBONATION:
This is normal and might happen, especially when carbonating very cold water. The
ice will quickly dissolve and you can enjoy your drink extra cold!