SodaStream E1 / Red Light — CO2 Cylinder Not Attached

What Does This Error Mean?

SodaStream shows E1 or a red warning light when it cannot detect a CO2 cylinder properly inserted and sealed. The machine will not carbonate until the cylinder is correctly seated.

Affected Models

SodaStream Source
SodaStream Fizzi
SodaStream Crystal
SodaStream Terra
SodaStream Art

Common Causes

CO2 cylinder not screwed in fully — the thread needs to be tight
Cylinder is cross-threaded and not seating straight
Cylinder is completely empty and has no pressure
Rubber O-ring seal on the cylinder neck is damaged or missing
Cylinder is not a genuine SodaStream cylinder (incompatible thread)

How to Fix It

Remove and re-insert the CO2 cylinder

Unscrew the cylinder fully, then screw it back in slowly and firmly. It should turn clockwise and tighten snugly — you will feel slight resistance as the seal engages.
Check the cylinder is not cross-threaded

If the cylinder feels loose or wobbles, remove it and start again. Place it straight against the thread before turning.
Check if the cylinder is empty

Shake the cylinder gently — an empty cylinder feels very light and makes no sound. An empty cylinder needs replacing, not re-seating.
Inspect the O-ring seal

Look at the top of the cylinder where it meets the machine. There should be a small rubber ring (O-ring). If it is cracked, missing, or deformed, replace the O-ring or the cylinder.
Try a different cylinder

If you have a spare cylinder, try it. If the new cylinder works, the first one is likely empty or has a damaged seal.

When to Call a Professional

No — this is a user-serviceable issue in almost all cases.

SodaStream E1 / Red Warning Light

Your SodaStream checks for a properly attached CO2 cylinder before allowing you to carbonate. If it detects no cylinder, or if the cylinder seal is not gas-tight, it will refuse to operate and show E1 or a red light.

The Fix Is Almost Always the Same

Remove the cylinder and screw it back in slowly, making sure it is perfectly straight and tightened until you feel the seal engage. This resolves the problem in the vast majority of cases.

When to Replace the Cylinder

Very light weight (empty)
Hissing sound when you attach it (damaged seal letting gas escape)
Machine shows E1 even with a known-good cylinder (machine sensor issue — contact SodaStream support)

Frequently Asked Questions

How tight should I screw in the SodaStream cylinder?

Tighten it firmly by hand — no tools needed. You should feel the seal engage (a slight resistance) as it seats. Do not over-tighten to the point of forcing it.

Can I use third-party CO2 cylinders in my SodaStream?

SodaStream uses a proprietary thread on most models. Third-party cylinders may have a different thread pitch and will not seal correctly, triggering E1. Always use genuine SodaStream cylinders or certified compatible replacements.