Metallic Flavours In Beer – Possible Causes

Nobody enjoys metallic off-flavours in beer. Detecting metallic flavours at low-levels can remind you of blood in your mouth. At higher levels, the flavour becomes coppery, like a 2p piece. But don’t go sucking any coins to find out.

If you have metallic flavours in your beer, it could be coming from something metallic in your brewing system. If you want to get rid of this off flavour, you’ll need to remove the problem from your brewing system. Metallic flavours can also manifest from old or improperly stored crushed malt.

If you suspect your brewing system, you’ll have to look at everything metallic that your wort comes into contact with, such as: 

• Mash tun
• Kettle
• Fermenters and taps
• Counterflow or plate chillers
• Any metal pipework

If your beer suffers from a metallic off flavour, consider these points: 

• Stainless steel gives you the best chance of beating any metallic off-flavours.
  • Stainless Steel is used by professional brewers for a good reason. It’s virtually inert and offers the best insurance against metallic off-flavours. 
  • Stainless is expensive, but it lasts forever as long as you don’t mistreat it by using highly abrasive cleaners, causing scratches. Also, don’t use bleach cleaners on stainless, which can cause micro-pitting if you leave it in contact too long.  
• Water can be a cause of metallic off-flavours in beer, but not as likely as something metal in your brewing system.
  • Using water high in iron can lead to metallic off-flavours. If you have high iron levels in your tap water, consider a carbon filter or use bottled water. (This point isn’t usually an issue in the UK).
• Old and pre-crushed or improperly stored malts can also cause metallic flavours in beer.
  • Always buy and use fresh malt from your local homebrew supplier. Keep it stored in a cool, dry area.

Conclusion

In conclusion, your best chance of avoiding metallic off-flavours is by buying top-quality stainless steel components and keeping them clean. Always use the right methods and cleaners, like Percarbonate or PBW dissolved in 40-60C water pumped around the system to Clean In Place (CIP). Looked after properly, stainless steel brewing equipment will last you a lifetime.

Also, always buy the best and freshest malt possible, and store it correctly. Uncrushed malt will keep longer. If you buy crushed malt, use it as soon as possible and try not to let it go over 6 months old. It will however be mostly fine to use for up to 12 months,