Brew Kettle Has Rust Inside (How To Clean It & Prevent It!)

The sight of rust in a brew kettle could cause concern to a brewer, especially if the said brew kettle is stainless steel. One of the main reasons a brewer will spend a little more on a stainless steel brew kettle is not dealing with rust issues.    

A stainless steel brew kettle is designed to resist rust, but it is not rust-proof. To prevent the formation of rust, clean the kettle with a brewing grade cleaner immediately after purchase. Only use tools that are safe for stainless steel, and dry the brew kettle completely before storing. If rust does occur, clean with Bar Keepers Friend.

Read on to find out what steps you can take to remove any existing rust that may have formed. You can also take steps to prepare your brew kettle to help prevent any rust from forming at all.

Why do stainless steel brew kettles rust?

Failure to maintain a stainless steel brew kettle will lead to rust. There is a minimum of 10.5% chromium found in stainless steel.

When chromium reacts with oxygen, an oxide layer forms very quickly on the surface of the steel, protecting the steel from rusting. Any damage inflicted to this oxide layer will allow the rust to start to form.

Improper care of the stainless steel equipment will cause it not to uphold its rust and corrosion-resistant capabilities. Using cleaners that contain bleach or ammonia and other types of harsh abrasives will damage the oxide layer that protects the stainless steel.

Excess scouring, using a non-stainless scour to scrub, or even placing non-stainless items in the kettle, will scratch up and damage your stainless steel brew kettle, enabling rust to form on these damaged areas. 

Do all stainless kettles rust?

If not cared for properly, all stainless brew kettles have the potential to rust.

Stainless steel is non-corrosive and rust-resistant, not rust-proof. Poor care and handling will ultimately result in a stainless kettle that will contain rust.

Stainless brew kettles do not claim to be rust-proof. However, they do have rust-resistant capabilities, which are only valid if the equipment is cared for adequately. If cared for properly any stainless steel kettle will resist rust and other corrosives. 

When cleaning, it is crucial to use the right cleaners, such as a brewer wash like Star San, PBW, or Oxygen Brewery Wash, to help ensure a good clean while still protecting your equipment. Use a scour scrub made out of stainless steel like the one from Scotch Brite to ensure no scratching or the risk of scratching up the brew kettles surface when scrubbing. 

Remember not to scrub excessively, even if using a stainless steel scouring scrub.

Is rust inside a brew kettle harmful?

A little bit of rust inside your brew kettle is not harmful, but you run the risk of ruining your brew.

Even in small quantities, rust in your brew kettle could increase the risk of a lousy brew due to the addition of a likely contaminant in the form of rust. Besides a failed brew, it is also rather unsightly to see in your kettle. It is essential to handle any rust issues timely since any rust issues will worsen over time. 

It is relatively safe to say that we (unknowingly) ingest rust through several different sources (water pipes, a rusty bottle cap, etc.) regularly.

The difference is knowingly using equipment that has rust that could be an issue making it more unsightly than harmful. Knowing that you brewed using a rusty kettle may cause concern also to the quality of your beer, by the risk of spoiling and tainting a brew with rust.

How to clean off a stainless steel brew kettle

If your stainless steel brew kettle has rusted, you will need to thoroughly clean and sanitize it before brewing again.

One popular cleaning option is using an oxalic acid cleaner like Bar Keepers Friend. Start by pouring some Bar Keepers Friend into your brew kettle, adding just enough water to make a paste to apply on the rusted areas. Let the cleaner set between five and ten minutes. Wipe off gently using a soft, dry cloth. 

Passivating is another way you can remove rust. Passivating works by using a mild acidic cleaner on your stainless steel brew kettle, which enables the oxygen that is present in the air to bond to the chromium, helping to reinforce the stainless steel.

A brewer should passivate their equipment at the first sign of any rust to prevent the issue from worsening. 

To passivate your stainless steel equipment:

  1. Clean your stainless steel equipment.
  2. Add Bar Keepers Friend to the affected area.
  3. Add water to form a paste.
  4. Rub the paste on rust stains and allow to air dry for five to ten minutes.
  5. Use a dry, soft cloth to wipe out the paste (do not use water).

How to keep a brew kettle from rusting

But why wait for the rust? You can protect your stainless steel brew kettle by passivating it before use.

Before use, clean the brew kettle thoroughly using a brewing grade cleaner to remove any debris that may scratch the surface of your kettle. Continuing to passivate your equipment after use will ensure that it stays scratch-free. All to dry completely before storing.

Proper care will help to ensure that your equipment will last. When it comes to a stainless steel brew kettle, handling is crucial, especially when it is not in use. From the time it is first used to when it’s time to upgrade, the life expectancy of your equipment will be determined by how well you keep it. 

Cleaning your stainless steel brew kettle after you first purchase it is important.

Cleaning it will help remove any debris (especially unseen) that may have come from the manufacturer and the retailer. Clean your stainless steel equipment with a brewing grade cleaner to remove any contaminants and debris inside. 

Make sure only to use equipment that is safe to use on stainless steel. This will help to prevent any damage that could occur from stirring or handling. When cleaning, use a safe cleaner on stainless steel equipment, and scrub minimally using a stainless steel scouring pad or cloth.

When not in, use do not place anything inside them.

And when drying, do not stack equipment for them to dry correctly. Stack at an angle upside down on a drying rack to allow any moisture to dry.