Kitchen Knife Edge Retention

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A Rockwell rating is an indicator of how hard the knife is. In general, the lower the Rockwell, the less the edge retention (less sharp and lose sharpness faster). However, lower Rockwell knives are more durable (when it comes to bone cleavers, they tend to use lower Rockwell knives to compensate for the impact and have a steeper sharpened angle of around 45 degrees per side). Higher Rockwell knives have longer edge retention (can hold the sharpness for a longer period) but lose durability.

If you have to give the Rockwell an edge retention timeline for home use, you get something in these timeframes:

  • HRC 51 – 5 min *
  • HRC 52 – 1/2 days *
  • HRC 53 – 3 days *
  • HRC 54 – 1 week *
  • HRC 54 – 1/2 weeks *
  • HRC 55 – 1/2 weeks *
  • HRC 56 – 1/2 months *
  • HRC 57 – 2/3 months *
  • HRC 58 – 3/4 months *
  • HRC 59 – 4/5 months *
  • HRC 60 – 5/6 months *
  • HRC 61 – 6/7 months *
  • HRC 62 – 7/8 months *
  • HRC 63 – 8/9 months *

+ Regular honing with a honing rod before needing whetstone maintenance if used at home for double ground knives (sharpened on both sides). **

*The above indicator is based on my personal experience in a restaurant setting and based on all-purpose knives and not specialized knives.

**Warning: You should never use a honing rod on a single bevel knife. (Yanagiba’s, Sakimaru, Deba, Unagisaki etc.)

How did I come up with the above indicator?

It is tested in a restaurant setting where we prepare a standard menu with the same ingredients (we do hours of prep work within a team setting. Which means one person does 30+ min of cucumbers only, and the other does the salad in 30+ min, etc.).

We need to portion size the Tuna to slice for sashimi
We need to portion size the Tuna to slice for sashimi

Of course, other factors play a role in what you use it on, how much force you use, how you cut, how heavy the knife is, at what angle the knife is sharpened, and what blade steel is used. I have added the indication since many of the viewers wanted a rough estimate. I converted it for home use for approximately 5/10 min a day.

Professional kitchen:

Rockwell 56: Knife died after approx. 30/45min. (Victorinox manages to reach 45min. Some other cheaper brands manage to survive 30 min despite the claim of a Rockwell of 56)
Rockwell 57/58, They manage to get the job done longer, but a hone is needed after the prep was done (approx. 1.5/2 hours).
Rockwell 60/61, It managed to survive 4 hours, but a hone is needed.
Rockwell 63+ survived for 2.5 days (10 hours before a hone).

For home use, this all depends on how many knives they have, how often they cook, and how well they take care of them. (see chart above)

This is based on my experience with knife Rockwell and how I got my estimates while testing the knives in a restaurant setting.

Regular restaurant prep work

Prep work on a Friday, 60 avocados (we use paring/petty knife, and for dragon sushi rolls, we use a thinner knife like a petty/utility knife), 60 cucumbers, 8 mangoes, 12 lettuce, 3 red leaf lettuce, 20 whole salmon, Tuna, 25 kilo’s (Approx. 55 pounds), 2 whole beef tenderloin (probably 3kg each 6.5 ish pounds) and more fish like sea bass, etc.
These are only the Sushi prep, excluding Teppanyaki and warm dishes, we have a sushi team of 5 to cover these, and it needs to be done before 4 PM since we need to eat staff meals at 3 PM before the rush hour/when guests arrive.

Tuna, portion-sized sinew, and bloodline removed, ready for storage or to be sliced into sashimi or nigiri slices.

If we split the team of 5, we have approx. have 4 hours to prep everything. 5 times a day, 4 hours prep every day, and depending on which station you cover, you may use the knife for 7/8 hours.

Rockwell 56: Knife died after 30-ish cucumbers a hone is needed (approx. 30/45min).
Rockwell 57/58, They manage to get the job done longer, but a hone is needed after the prep was done (approx. 1.5/2 hours).
Rockwell 60/61, It managed to survive 4 hours, but a hone is needed.
Rockwell 63+ survived for 2.5 days (10 hours before a hone).

The above timeframe is for veggies prep only.

If we take the above time and translate it to home cooks 5 min (5 minutes of actually cutting) prep a day (they are slower in prep and prep less per day):

Rockwell 56: 9 days
Rockwell 57: 18 days
Rockwell 58: 24 days
Rockwell 60+: 48 days
Rockwell 63+: 120 days

And that is without honing and only veggies prep.

Above with honing, you can get longer edge retention and most likely even double the days, and you can even hone more often after one honing session.

Rockwell 56: 18 days
Rockwell 57: 36 days
Rockwell 58: 48 days
Rockwell 60+: 144 days
Rockwell 63+: 240 days

This is a rough estimate since I was asked to add an edge retention timeframe in the videos. I just had fun with some rough calculations, but this pretty much says that you don’t need a stone for a long period if honed correctly with high Rockwell knives. And above is assuming you cook no cheat meal/ visiting restaurants (so some will experience longer edge retention than others etc.). In the end, I came up with the first chart to give everyone a rough estimate.

You can leave your questions in the comment section below.

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  1. Thank you so much! This information is very helpful for a beginner like myself.

    My plan is to maintain just one high-quality kitchen knife and delegate the task of sharpening to professionals. Having it professionally sharpened every six to twelve months could save me the expense of purchasing specialized sharpening equipment and alleviate concerns about potentially damaging my knife due to improper sharpening practices. I’ve noticed that many kitchen knife enthusiasts own an array of knives and maintain them to exacting standards. However, for someone like me, who simply requires a reliable knife, wouldn’t professional sharpening be a practical solution? This seems particularly relevant for durable yet somewhat ‘complex’, knives made from very hard steel. Or, am I overlooking something?

    1. Getting the knives professionally sharpened is a good option, just make sure the company or person doing it is knowledgeable and not doing a belt grind sharpening on some knives. This simply varies per country and location.

      Here in the Netherlands, only a select few stores offer professional manual sharpening services, and only a select few offer replacement knives while they sharpen your knife. These shops sharpen a lot of restaurant knives so they have a long-standing relationship with the restaurants.

      And if you want the factory aesthetic back they can get the mirror polish back and even go beyond the factory look. So removing all the scratches on the blade, they can thin the knife too. All for a fraction of the cost /time compared to getting all the tools, equipment, experience, and knowledge that is required.

      So you are not overlooking anything but just find the proper store/sharpener that you can trust that will take care of your knife.

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