Sharpening Knives

  • We aim to introduce our customers to a knife sharpening guide to help them maintain the sharpness of their knives and prolong their enjoyment of cooking. Our hope is that our customers can savor the pleasure of using knives while enhancing their culinary experiences even further.

  • The Importance of Sharpening Knives

    With each cut, the blade of any tool encounters resistance and wears down. If left unchecked, the edge will chip, dull, or become unusable. The purpose of sharpening tools is to restore their sharpness and return them to their original condition. This is especially important for knives because their sharpness has a significant impact on the taste, texture, and quality of food. Professional chefs understand this impact. In fact, studies have used sensors to measure the taste of tomato extracts cut with both sharp and dull knives. The results showed that extracts from tomatoes cut with dull knives had more than twice the bitterness and astringency of those cut with sharp knives, with a slight increase in saltiness and a decrease in acidity. You may also have noticed differences in moisture release and shape integrity when cutting the same food with a dull knife versus a sharp knife. Understanding how this affects flavor and texture underscores the importance of sharpening knives to maintain their cutting edge.

  • Before Sharpening Knives

  • In this section, we will cover essential knowledge for anyone who sharpens knives. By keeping these points in mind, you'll find it easier to address any questions or issues that may arise during the sharpening process.

  • 1.The Importance of the Backside on Single Edge Knives

    For single-edged knives, the role of thebackside—shaped by the back pressure during sharpening—is crucial for achieving optimal sharpness. The back of a single-edged knife features a specific design called"ura-suki,"where part of the steel is removed toreduce cutting resistanceandsimplify sharpening.

  • This design is only effective if the back edge is properly maintained. Ideally, the back edge should be very thin, typically less than0.5mm, known as a "thread back."Oversharpeningthe backside can thicken this edge unnecessarily, increasing resistance when cutting ingredients and consequently reducing the knife’s sharpness. This principle also applies to other types of knives, like theDeba, which is used for cutting hard materials. Here, a slight thickening of the back edge can helpprevent chipping. Adjusting the edge based on its intended use is crucial for maintaining the knife’s effectiveness.

  • 2. The Chef's Defense is on the Surface

    Single-edged knives feature what is called"ura-suki"on the back, which is crucial for sharpness. It is generally fine to lightly press to maintain a clean back edge. However, with prolonged use, there is a risk that the back edge mightspread and become dulldue to excessive pressure, or it might not contact the whetstone properly due to distortion or other issues. In such cases,specialized equipment is needed to correct the back grinding.

  • This falls under "repair," not "sharpening," and is typically beyond even professional chefs' expertise. Similarly, if a blade is badly chipped, it is advisable tosend it for repairrather than attempting to fix it with a rough whetstone.Regular sharpeningis crucial for honing one's skills, but understanding the limits of what can be achieved at home and knowing when to seek professional help is important. It is also wise tokeep several knivesof the same type on hand in case of problems.

  • 3. Setting Sharpness Goals

    The goal of sharpening a knife is to achieve a level of sharpness that is appropriate for its intended use. While ideally, all knives should be sharp to preserve the taste, texture, and quality of food, an extremely sharp edge is not always necessary in the kitchen.

  • For instance, knives used for cutting hard materials, such asDebaandGarasaki, are prone tochippingif the edge is overly sharp. This can compromise the blade's sharpness, necessitating frequent re-sharpening to repair the damage. Moreover,over-sharpeningother kitchen knives can significantly alter the feel compared to the knife you use daily, which could negatively impact yourwork efficiency. It is important to consider the degree of sharpness that suits your specific needs and motions. One of the objectives in sharpening should be toavoid excessive sharpness.

  • 4. Understanding "Kaeri"

    In sharpening, the terms"Kaeri," "Ha-gaeri,"and"Bari"all refer to the same phenomenon: aflake of metalthat forms at the tip of the sharpened edge. As a knife is sharpened, the edge becomes thinner, and if sharpening continues, this metal flake appears on theopposite sideof the sharpened surface.

  • The presence of "Kaeri" indicates that the sharpening work at that stage is complete. However, having a lot of these flakes is not necessarily beneficial.Excessive "Kaeri"can lead to unnecessary removal of blade material, socautionis needed. Additionally, as the sharpening process nears completion, the amount of metal being removed decreases, and the "Kaeri" will tend to becomesmaller. It is important to bevigilantand not overlook this sign.

  • 5. What to Do with the "Mud" That Comes Out of the Sharpening Process

    Sharpening knives produces a substance commonly referred to as "mud," which is actually a mixture of metal particles from the knife and abrasives from the whetstone. Many experienced sharpeners advise not to wash this mud off the whetstone during the sharpening process. The mud itself possesses abrasive properties that can enhance the sharpening, making the process quicker and more efficient.

  • However, managing this mud can be challenging. Too much mud may lead to unintentional sharpening of parts of the blade that should remain untouched, making it difficult to precisely control the blade's edge. To address this, some opt for "running water sharpening," where the mud is rinsed off during sharpening, which is particularly useful for fine-tuning the edge as it relies solely on the whetstone's abrasive power. Effectively adjusting the amount of mud and switching to running water sharpening when necessary can optimize the sharpening results.

  • Selecting the Right Whetstone Grit

  • The process of achieving a sharp knife starts with choosing the correct whetstone. The grit of the stone influences the sharpness and polish of your blade:

    • Rough Stones (240-600 Grit):
      Suitable for repairing damaged edges or creating a new edge. These stones remove material quickly and efficiently.
    • Medium Stones (800-2000 Grit):
      Ideal for refining your blade's edge. This range of grit smooths out the roughness left by coarser stones and prepares the edge for final polishing.
    • Finishing Stones (3000-8000 Grit):
      Used for achieving a mirror-like polish and an exceptionally sharp edge, ideal for precise cuts.

  • Remember, grit numbers might vary between manufacturers, so it's important to follow the guidelines specific to your whetstone brand.

  • Step-by-Step Knife Sharpening with a Whetstone

  • 1. Assess Your Blade:
    Before sharpening, inspect your knife for any chips or nicks to ensure a smooth edge.

  • 2. Soak or Wet Your Stone:
    Water acts as a lubricant, reducing friction and preventing heat build-up that can damage the knife. Ensure your stone is adequately moist, whether soaked or wet during use.

  • 3. Find Your Angle:
    The angle between your knife and the stone is crucial for effective sharpening. Typically, this is between 20-30 degrees, but it can vary based on the knife and personal preference. Consistency in maintaining this angle is key.

  • 4. The Sharpening Motion:
    With gentle pressure, glide your knife back and forth over the stone, maintaining your angle. Use smooth, even strokes for the best results. Flip the knife periodically to sharpen both sides evenly.

  • 5. Clean and Dry:
    After sharpening, rinse and dry your blade and whetstone to ensure they are clean and ready for next use.

Type of Whetstone

When you acquire a good knife, it's equally important to find a suitable whetstone to mWhen you acquire a good knife, it's equally important to find a suitable whetstone to maintain it. In this section, we will explore theimportanceandrecommended frequency of usefor various types of whetstones.

Type of Whetstone
Type of Whetstone

Daily Care of Whetstone

While whetstones are crucial for knife maintenance, you might wonder if they require any special care themselves. Although they generally do not need much attention, the most serious issues they can encounter—akin to rust on knives—are warping and denting. It's important to know what to watch for to prevent these problems and ensure your whetstone remains in good condition for clean and effective use.

Daily Care of Whetstone

KIREAJI's Three Promises to You

  • japanese_knife_made_in_Sakai

    1. High-quality Japanese Knive

    We offer knives crafted by craftsmen from Sakai City.

  • Honbazuke

    2. Genuine Sharpness

    To ensure you experience sharpness, we provide a free Honbazuke by our skilled craftsmen.

  • 3. Lifetime Knife Use

    Every knife comes with a free Saya(Sheath) for durability. We also provide paid after-sales services with Sakai City Japanese knife workshop.