There are a number of ways to tell when your gas cylinder is empty:
1. When you press the carbonating button you don't see any gas going into your bottle of water
2. Even after repeated presses your water is not carbonated
3. You hear a spluttering sound when you attempt carbonation
Click here to exchange your empty gas cylinder with a new one.
Pro-tip: SodaStream recommends keeping a back up gas cylinder handy so that when one cylinder runs out, you simply swap the empty cylinder for a full one. That way, you'll keep enjoying fresh, sparkling water based drinks without interruption and can exchange the empty gas cylinder online through sodastream.co.uk or in a store near you.