To clean a Corny keg, disconnect it from gas and beer lines, release all pressure, disassemble the accessible fittings, remove beer residue with a compatible brewery cleaner, and rinse thoroughly. Sanitize the clean keg and its beer-contact parts before refilling. Washing the stainless shell alone is not enough: dip tubes, poppets and seals can retain residue where you cannot easily see it.
A Cornelius-style keg is serviceable, but different models use different posts, thread sizes and internal parts. Identify your keg before loosening anything. Keep its manufacturer instructions nearby, particularly for pressure limits, replacement seals and cleaners. Do not assume every ball-lock or pin-lock keg can accept the same parts.
Make the keg safe to open
Close the gas supply and disconnect both quick-disconnects. Vent the keg through the designated pressure relief or the manufacturer-approved procedure for that model. Keep your face away from the opening and confirm no pressure remains before releasing the lid. If a fitting is stuck or the relief valve does not work, stop rather than forcing it open.
Pressure is relevant even when the keg seems empty. Residual carbon dioxide can remain after the last beer is served. Hot cleaning solution can also produce pressure in a closed vessel. Never heat a sealed keg or remove posts while it is pressurized. Use appropriate gloves and eye protection specified by the cleaner label.
Work on a stable surface with a tray for small parts. Take a photograph of the assembled posts if their identity is unclear. Mark gas and liquid components so they return to the correct side. The long liquid dip tube and short gas tube serve different purposes, and swapping posts may prevent correct connections.
Drain and inspect before soaking
Empty the remaining beer and rinse away loose sediment before it dries. Inspect the inside with a light, especially the bottom, shoulder and lid opening. Look for sticky deposits, obvious corrosion, damage and foreign objects. A used keg with unknown contents deserves a careful initial inspection and replacement of questionable seals.
Check the lid gasket, post O-rings, dip-tube seals and poppets for cracking, cuts, flattening or lingering odor. Cleaning cannot repair a damaged seal. Replace worn parts with components specified for your keg rather than relying on extra lubricant to compensate. Food-grade keg lubricant may help appropriate seals seat, but it is not a disinfectant.
If the shell is dented, badly corroded or has an uncertain pressure rating, do not treat cosmetic cleaning as a safety assessment. Ask the supplier or manufacturer whether the keg remains suitable for service. A bargain keg can become expensive if its history or fittings make reliable use impossible.
Disassemble the hidden beer paths
Remove the posts with the correct tool after depressurizing. Lift out dip tubes and seals, and dismantle removable poppet parts according to the keg design. Some assemblies are captive; forcing them apart can cause damage. Keep each post’s components together in a separate marked container.
Clean the long liquid tube internally with a suitable tube brush or the manufacturer’s recommended process. Check the tube opening for hop particles and dried deposits. Inspect the underside of the posts, spring areas and gasket seats. Small channels matter because all served beer eventually passes through them.
Disconnects, serving hoses and faucets need their own cleaning routine. A perfectly clean keg connected to a dirty liquid line will still serve beer through that contaminated path. Our beer faucet guide explains why easy access for cleaning should influence equipment choices.
Use the cleaner correctly
Mix a brewery cleaner compatible with stainless steel and the keg’s seals at its labeled concentration. Follow its temperature, contact time and material restrictions. More powder and hotter water do not automatically improve the result. Household scented detergents can leave odors, while abrasive pads can damage surfaces and make future cleaning harder.
Give the shell and removable parts complete exposure to the cleaning solution. Use a soft brush on visible deposits where appropriate. If a deposit persists, repeat a compatible cleaning cycle rather than scraping aggressively with metal. Never mix cleaning chemicals or combine acidic sanitizer with an alkaline cleaner.
Drain the cleaner and rinse the keg, tubes and fittings thoroughly with potable water. PBW and similar brewery cleaners are cleaning agents, not no-rinse sanitizers. Cleaner residue must not remain in the keg simply because the next step will use sanitizer. Five Star’s product guidance specifically addresses rinsing PBW.
Reassemble and sanitize
Inspect all parts again after rinsing, then reinstall the correct seals, tubes and posts. Tighten fittings according to the equipment instructions, avoiding excessive force. Ensure the lid gasket is seated without twists. A little suitable lubricant is useful only where the manufacturer recommends it; coating every surface is unnecessary.
Prepare a food-contact sanitizer exactly as labeled. Wet every beer-contact surface for the full specified contact time, including the lid, liquid post and dip tube. If pushing sanitizer through a line with carbon dioxide, use the keg’s approved operating limits and a controlled gas supply. That technique must not substitute for prior disassembly and cleaning when deposits are present.
Drain according to the sanitizer instructions. A correctly diluted no-rinse product may require draining without a water rinse; another product may have different directions. Do not towel-dry sanitized interior surfaces. A towel can introduce lint and microorganisms immediately after you have completed sanitation.
Check sealing before filling with beer
Verify that the reassembled keg holds pressure at an appropriate setting within its rating. Inspect connections and the lid for leaks using the supplier’s recommended method. Release pressure safely before any adjustment that requires opening or disassembly. A leak can waste gas and compromise storage, even if the keg appears clean.
If a post leaks, check its O-ring, poppet and matching disconnect instead of repeatedly tightening it. If the lid leaks, check the gasket and seating surfaces. Keep a small supply of model-correct replacement seals so you can fix a problem before beer is ready rather than improvising during a transfer.
Build cleaning into the serving routine
Rinse a keg soon after it empties and record any parts replaced. Store it drained and clean as the manufacturer recommends; sanitize again close to filling. Label it as clean or awaiting cleaning so there is no uncertainty on packaging day. Our cold keg guide covers the separate problem of managing serving temperature.
For an illustrated breakdown of typical keg parts, consult MoreBeer’s kegging instructions. Treat generic diagrams as orientation, not a substitute for your model’s specifications. A successful routine leaves the shell, small fittings and serving path clean, rinsed, correctly assembled and ready for sanitation.