A Simple Guide to Removing Patina from Your Carbon Steel Knife
Many kitchen knives are usually made from carbon steel. Carbon steel has its advantages. It is a harder steel type and the blade stays sharp for a longer duration of time than a blade made from stainless steel which has to be sharpened from time to time.
Also, from a utilitarian standpoint and perhaps one of the main reasons why carbon steel knives are so popular with chefs is that they are easier to sharpen than knives made from stainless steel. This is an important quality because a knife will not stay sharp for long if it is used frequently. For a knife to be perform well and work with precision sharpness, you need it to be sharp at all times.
Carbon steel knives may be desirable but one disadvantage (or advantage, depending on an owner’s preferences) they exhibit over time is that they develop a patina after a few months of use.
The patina forms out of a natural oxidisation process that happens when the naturally-occurring oxygen in the air combines with the iron in the carbon steel and other metals to form an oxide layer on the blade. The patina might also form from the light corrosion that happens when you use the knife to cut slightly acidic foods such as tomatoes and leave the knife unwashed for long durations of time.
The patina can be an attractive feature in a kitchen knife and some chefs actually love the organic oxide layer that forms on their blades over time. It is a testament to the knife’s utility over time and it gives the knife a vintage aura.
The patina can also be ghastly. If you have a beautiful knife finish, the patina that forms over it with time will conceal the delicate finishes on your knife.
If you are using a carbon steel knife, you simply can’t avoid the patina. The longer you use the knife, the tougher that patina becomes and the harder it is to remove. That is why most chefs always look for ways to quickly offset the patina before it gets worse. Patina removal is also one of the top knife restoration measures, particularly for carbon steel knives.
Should You Get Rid of Patina?
Most of the knife patina will simply be mild discoloration. The knife won’t have a massive scale build-up or corrosion but it will be discoloured nonetheless. Any stain on the knife that is neither dirt nor rust should be regarded as patina.
Most of the patina will actually be a good thing for your blades. Once a layer of oxidised steel is formed over the blade, it won’t oxidise anymore and the patina therefore protects your blade from severe corrosion, rust and further degradation. Depending on the uses you are planning to put your knife to, it may be worth simply leaving the patina there.
Besides, refinishing the knife to get rid of the patina may sometimes ruin the value of the knife, particularly if you are planning to resell a high-grade knife at a later date. However, unless you are holding a high-grade knife or collector’s item, preserving the original value of the knife may be the least of your concerns. If your knife is for your day-to-day cooking chores and all you want is to restore its original sheen, then by all means, you should try out the various techniques that we have listed below for removing patina from a kitchen knife.
There are various ways of removing the patina from your kitchen knife. These include the following: -
- Steel wool
- A rust or patina eraser
- Sodium bicarbonate or baking soda
- White vinegar
- Steel wool
- Simichrome Polish
Polishing is a refined way of removing the patina. It entails getting rid of very small amounts of the metal. It smooths out the grain and surface of the kitchen knife while leaving the manufacturer’s original and detailed finishes intact.
If you are traveling this road, be careful not to over-polish. If you overdo it, you may end up with something somewhere between a mirror finish and rough sanding. That is, you will polish past getting rid of the patina and end up altering the knife’s original finish.
Any metal polishing compound should work on a patina. However, go for the polishing compounds that have been specifically made for carbon steel such as the mother creams. When polishing, take care not to polish the sharp edges of the knife.
Like with polishing, sanding must be done carefully to ensure you don’t go beyond the patina removal stage and start refinishing your knife.
Sanding entails the use of abrasives to remove the patina and it is advisable to use products that are the least abrasive for this purpose. You can use automotive-grade sandpapers or the typical abrasive materials used to clean utensils.
When it comes to sanding, it is advisable to begin removing the patina using the highest grit sandpapers. Always lubricate the sanding process with oil or water.
Take off all the patina on the blade and start working your way back to the sandpaper with the highest grit. You can subsequently refinish the blade by buffing it with a less abrasive material such as scouring pads, surface scrubbers, foam scourers or sponge scourers.
Baking soda or sodium bicarbonate is also an effective compound to use to get rid of the patina on your blade. Through a chemical process, the baking soda will react with the iron oxide layer that constitutes the patina to get rid of the discolouration.
Start by making a paste consisting of a mixture of the baking soda and water. You can substitute water with lemon juice to make this paste more acidic and increase its potency, particularly if you have a heavy layer of patina or rust.
Wash the knife and get rid of any dirt before you apply the paste.
Apply this paste on the patina on the blade and use a scourer or light scrubber to gently rub off the patina with the baking soda paste.
Avoid using very abrasive material such as steel wool as they will scratch the knife’s surface and alter its original finishes. Once the patina is gone, use a dry towel to wipe off the paste and clean the knife.
Sodium bicarbonate is better suited for light patina.
Simichrome polish is one of the best materials for removing patina from your kitchen knife. It is less messy and very effective at getting rid of the patina. Most professionals and knife restoration experts use it.
It does an excellent job of getting rid of the patina. It doesn’t scratch the knife, gets rid of all the patina while also polishing the blade to a pristine shape. You can use it to spruce up your kitchen knives without leaving any abrasive marks or scratches, ensuring the manufacturer’s unique finishes stay intact.
This is also an ultra-efficient way of getting rid of the patina on your blade. It is so quick it can even take a few seconds. It can rejuvenate the faded metal to create a perfect mirror finish or restore the original lustre of the knife.
Besides, the Simichrome Polish will also leave your blade with an invisible but protective coating that helps retain the shine on the blade for a little longer.
White vinegar can also be effective at removing light patina and mild rust on your blade. It’s made of acetic acid which will react with the iron oxide and remove it from the blade surface that hasn’t rusted. If the knife is exhibiting some patina or mild rust, dip it inside white vinegar and leave it there for about 5 minutes.
Use a clean cloth to wipe the blade clean and get rid of the remaining vinegar.
Alternatively, you can soak a paper towel or cloth in white vinegar and then apply it on the discoloured part of the knife.
The blade should be in contact with the vinegar for not more than five minutes as the acetic acid might corrode it.
Techniques to Avoid When Removing Patina
Some techniques might get rid of the patina but are generally not recommended as they gouge out the knife or damage its finishes. These include: -
- Using a Wire Brush: It is ok to use a fine steel wool on the patina as it helps get rid of the discolouration very quickly and efficiently. However, avoid using a wire brush as it will simply scar and gouge the blade.
- Cheap sandpaper: Use the right sandpaper to remove the patina. It is generally recommended that you use very fine sandpaper. Using cheap sandpaper with coarser grit might also gouge your knife and ruin the manufacturer’s original finishes.
- Harsh Chemicals: We have recommended the use of baking soda, white vinegar and some metal polishes. Avoid using harsh chemicals as they can ruin and stain the blade further.