Füri FAQs

KNIFE CARE AND PRODUCT INFORMATION

“How should I maintain my quality professional knives?”

1. Keep your quality knives sharp!

No knives stay sharp forever, but professional knives can be kept sharp almost forever with some minimal effort. You have 4 broad choices:

1. Traditional combination of Steel and stone: the Steel daily, and the stone about once a month. With a lot of skill, a Steel can maintain a  sharp edge, but eventually the cutting edge will become 'rounded', from human angle error, at which time the cutting edge bevels must be restored by removing this rounded material (on a stone, or some other device/service).

2. Gadgets: can be simple and fast, but chefs don’t use them for a reason. We know technically why a ‘gadget edge’ is not satisfactory for professional knives, but chefs just know from experience that they don’t work.

3. Füri professional sharpening tools and systems: developed and patented by the mechanical engineers at Füritechnics, after years of primary research with one simple goal: to produce cutting edges that are honed like a professional on a Steel, but with none of the human angle error, so a perfect 20° bevel is created each side, quickly and easily, by anyone.

Knife sharpening need not be a mystery. Our sharpening pages are designed to remove the mystery and show the techniques that will build your skills. We have detailed descriptions and animations to describe knife sharpening options. Click here for more sharpening detail.

2. Don't let your knives rust!

The material used in professional knives is very different to sinks, pots and pans, forks and spoons, etc. It is less corrosion resistant, but much harder (to hold an edge under abrasive cutting conditions). Simply hand wash and dry your knives after each use. Don't leave them wet on the sink, and don't put them in the dishwasher. (Dishwashers are highly corrosive environments, and will literally eat a small layer of metal off your knives, making your fine edge rounded and dull, and leaving rust spots on your blade.) Also, the plastic sleeves many knives are packaged in are very humid environments, and your knives shouldn't be stored in them after purchase (use a good knife block or magnetic rack). If you do get small rust spots or  stains on your knives, simply scrub off the spots using a sideways (width-wise) scrubbing motion, using a scouring pad or cloth and metal polish. Never scrub along length-wise along the blade or handle, because this is across the original polishing grain, and will quickly show polishing scratch marks. Click here for more detail on corrosion of professional knives.

3. Don't use your knives as a lever to remove lids, etc, and avoid dropping them onto the floor!

Professional knives are hard and strong, but they can still be broken or chipped if enough inappropriate force is applied. Knives are only designed for straight-line forces in the vertical plane (normal cutting), and not for sideways leverage, or for striking against hard objects (including bones – chefs never swing their knives at bones!). Apart from the unnecessary destruction of a fine tool, and the inconvenience, the lifetime warranty is voided if they are abused in any of these ways. Please care for your knives: they will give a lifetime of good service if treated sensibly!

4. Handle your knives carefully when cutting! Build your cutting skills.

There are some simple techniques that make the food preparation process much more pleasant, faster, and safer. One of the key simple skills is the hand grip on the food, and using your knuckle as a guide on the side of the blade. Again, the easiest way to explain the techniques is to demonstrate them, so go to our cutting skills pages, and see animations of our Chefs demonstrating various cutting techniques for different kinds of food preparation. The next best thing to a live Chef demo!

5. Store your knives carefully to avoid damage to, and from, their edges.

The safe and hygienic storage of knives is a crucial issue in both domestic and commercial kitchens. Traditional and common knife storage methods such as wooden knife blocks or loose knives in a drawer have many drawbacks.  These include blunt knives, contaminated knives, damaged knives and increased injury risks.

The Füri Clean-Store Knife Blocks are the best possible way to store professional knives because they protect the blade edges (and users’ hands from the edges of the blades) and ensure the knives are easily accessible during food preparation and cooking.  Designed by Füritechnics, they are called ‘Clean Store’ because they are hollow inside and the slots are very shallow, which is more hygienic than the deep slots in regular wooden blocks which accumulate airborne grease and dust and are very difficult to clean.

“Should I remove the stickers on the knives before use, or are they permanent?”

All of the informational stickers that are affixed to the knives are meant to be removed and are not permanent.  Some are a little more difficult to remove than others, but all of them should be taken off before use. If a sticker leaves a gummy residue, use a gentle solvent to remove this residue, and hand wash and dry before use.

“Why have my ‘stainless steel’ knives developed rust spots or stains?”, or;

“Why do professional knives rust, when my kitchen sink doesn’t?”

There is a lot of misinformation around about knife material and design. One of the myths is that all stainless steels are the same. People assume that kitchen sink, fork, spoon, and saucepan material is the same as professional knife material, but the differences are more important than the similarities!

The material used in kitchen sinks, saucepans, tabletop forks and spoons, bench-tops, etc, is an austenitic stainless steel alloy. This material is designed for corrosion resistance primarily, being high in chromium and nickel, but is non-magnetic, relatively soft, and cannot be hardened. Therefore, it cannot be used for making professional knives.

The materials used in professional knives are various martensitic stainless steel alloys: this material is lower in chromium, with no nickel, magnetic, able to be hardened and tempered, and is less corrosion resistant (because of all the alloy elements needed to make the material hardenable).

Füritechnics designs and produces knives. We are engineers, not just importers and sellers of other countries’ brands. We chose the finest Japanese and German alloys for manufacturing our Füri knives, so they have the properties that are most important to professional chefs: holding an edge, toughness, and ease of sharpening. We weren't prepared to compromise on these properties, just to increase the stain resistance for home cooks who don’t care for their tools (and those ‘performance properties’ are always a trade-off with corrosion resistance).

Füri knives have the ideal balance of stain resistance and edge properties, because professionals always wash and dry their knives after use (and Füri knives will not stain with this simple care). Chefs are more interested in the performance of the blade material,and less interested in the ability of the knife to resist stains (or ability to be left wet in dishwashers or on sink tops).

This is the difference between Füri knives and fashionable knives: ours were designed to work better in every important feature for working professionals; Füri is primarily a professional knife. Because Füri also looks good, and is often recommended by chefs, colleges, food writers, etc, Füri knives have also become very popular with domestic cooks. Because many domestic customers don’t understand the differences between the various stainless steel materials we included care information on the packaging that comes with each knife, and on a prominent sticker on each knife.  We also clearly state that warranty does not cover rusting from lack of care.

There is never a problem with spotting of Füri knives when they are simply washed and dried after use. Because Füri knives are a stainless steel alloy, they won’t corrode under such conditions. Occasionally our knives will not be properly dried, and spots will form. It is simply a matter of polishing off the spot with a scouring pad or steel wool. Simply rub over the spot, width-wise in the direction of the original polish on the knife (not lengthwise, but across the width of the knife): in this way no scratches will appear on the material from the scouring pad. If you polish length-wise, along the blade, you will see fine scratches appear along the blade.

We put in the years of difficult development work to create a knife that simply worked better for professionals. The Füri knife is being called the best by many leading Chefs around the world. Of the hundreds of thousands of knives we sell every year, very few complaints are received about rust. With some knowledge (like the information here) and regular care, those who complain are soon able to learn how to maintain their knives without rust problems.

So, if you are willing to maintain your knives as recommended, you will experience many years of excellent performance from the same knife that expert chefs around the world recommend.

For an excellent independent source, please consider the opinion of the world’s leading authority on knife testing: the Cutlery and Allied Trades Research Association (CATRA) in Sheffield, England. Please feel free to visit the CATRA site to review their publication ‘Care of Cutlery’: www.catra.org

“Why shouldn’t I wash my knives in a dishwasher?”

You should never wash your knives in a dishwashing machine, but the reasoning has nothing to do with the heat. It takes a lot more heat for a much longer period of time to change the temper of knives (or any other hardened and tempered iron alloy). A dishwasher is not hot enough, nor the cycle long enough, to change the microstructure. The 'blunting' of sharp edges by dishwashers is related to the corrosiveness of the detergent solution: a very small layer of metal is 'eaten' off the knife; enough to 'round off' the small serrations that were created by honing on the Steel or Diamond Fingers.

Without a strong background in metallurgical studies, it is pretty hard to grasp. To make things more understandable, our website has a lot of technical information. The 'Caring for Professional Knives' section is a good summary, but the 'Tech Edge' articles (under 'Information') have good basic metallurgical information.

One of our goals is to reduce the misconceptions and increase knowledge of professional tools. We do this through our website, our brochures, and our trade shows (where Chefs and engineers talk about how really to sharpen, handle, and care for knives).

“Why is my Coppertail tarnishing, and how do I use it to rebalance the knife over time?”

The packaging of Füri Pro and FX knives has a summary of the knife’s high performance features and benefits. The relevant info about the Coppertail varies for some models, but essentially reads:

"World-first ‘Coppertail' counterweight for precision balance.  As the blade wears and becomes lighter over time, simply file copper from the tail to rebalance the knife (patents pending). Maintain the brightness of the Coppertail by polishing regularly or allow oxidization to occur for the copper to achieve its attractive natural patina."

To offer further explanation of this summary, the following detail may be helpful:

1. "World-first ‘Coppertail' counterweight for precision balance."  Our Coppertail is an important innovation in the world of 'serious' professional knives, because for the first time it allows a knife's balance to be easily adjusted by the owner.

2. "As the blade wears and becomes lighter over time, simply file copper from the tail to rebalance the knife (patents pending)."  We have patents pending on this 'world first'. Rebalancing is particularly important as the blade is sharpened away over time: the serious cook would grind/file away the solid copper tail to rebalance the knife, allowing it to feel like a new knife for many years to come. Every knife sharpening service, mechanic, or metal workshop has a bench grinder or coarse file that would enable them to quickly shave the copper down to your preferred balance.

3. "Maintain the brightness of the Coppertail by polishing regularly..."  This is one option for anyone who really wants to maintain a bright copper finish, like a shiny new penny. Just like copper pots, the Füri Coppertail is real solid copper, and the only way to keep it bright is to polish it. Regular metal polish and a soft cloth can be used, and a few 'twists' of the cloth around the Coppertail whenever oxidization appears would be sufficient. However, in practice, our opinion is this is impractical for most people, and that the natural patina of copper is more attractive in combination with stainless steel.

It is important that customers realize that Füri knives are not regular 'consumer' knives. They are designed first and foremost for real working chefs, and because they are high-performance professional tools, they will require some maintenance (sharpening and hand-washing at least). There are lots of other beautiful 'designer' knives on the market that are low-maintenance, but chefs do not use them because they are not designed for high performance in commercial kitchens. They do use Füri, however, because of all the development we put into creating the highest-performance knives today. The famous chefs use our products because they really work; not for fashion or kitchen decoration!

4. "....or allow oxidization to occur for the copper to achieve its attractive natural patina."  This is our recommendation. All our products are designed for working chefs, and they are very familiar with solid copper, and combinations of copper and stainless steel. They would never polish copper, for practical reasons. We intended the Coppertail to oxidize and take on the natural patina of copper. Most of the people who own our Coppertail knives agree (including Rachael Ray), and are very happy with the look of natural copper.

 “What is the difference between FX and Pro Knives in construction and materials?”

When we developed the Pro knives, the only available sharpening methods were gadgets or traditional steel/stone. Our research showed that the former didn't produce a correctly honed edge, and the latter required a lot of skill and still involved a lot of human error, but at least produced the correct hone for professional cutting situations.

Because of the difficulty in sharpening/honing of CrMoV knives with traditional Steel/stone, we worked on using an alloy that had the best combination of ease of sharpening (to sharpen/hone just like carbon steel), edge retention and corrosion resistance, for professional cooks.

While we were developing the new FX forging method, we also developed the Tech Edge sharpening system. It quickly became obvious that this sharpening system would finally solve the problem of sharpening/honing CrMoV materials, and that ease of sharpening as a material property would be largely redundant for anyone who owned Tech Edge. The German CrMoV material we use for FX is easily sharpened on Tech Edge, but will be as difficult to sharpen as other brands using traditional methods.

So, its advantages include slightly better corrosion resistance, and slightly longer edge retention (particularly if cutting on hard/abrasive surfaces). Its disadvantages include material cost (note the price difference between FX and Pro), and more difficulty in sharpening/honing with traditional sharpening methods.

The relative merits usually become irrelevant once a chef picks up and uses the FX knives: it is immediately obvious that they are something very special.

However, the properties and expense of FX knives are not as important for smaller knives, so we've only used this technology for our largest, hardest-working models.

“Why do short and long Füri knives have different balance points?”

We balance different models at different points, because they are used in different ways. Balance is only really of benefit for knives that are used very heavily and repetitively, in the rocking-sawing motion that chefs and skilled home cooks use.

Note that our largest Chef and East/West knives (from the 7” East/West up) are balanced on the blade close to the bolster, because this is where chefs always put their forefinger. Place your forefinger on the blade, along the bolster (transition point from blade to handle): this is where it will balance. That is the right place for chefs who use this grip.

The 5” East/West is different: we wanted to balance it for more of a ‘household’ grip, where the forefinger is more commonly placed in the groove of our handle.

If you try our larger knives (8”, 9”, 10”), you will find that the balance point moves further away from the handle: this is because chefs will tend to grip these further forward for more control of their large blades.

The nice thing about the Coppertail – and the reason we patented it – is that cooks can grind the copper off to balance it in any way they prefer, or rebalance it as the blade wears down smaller (and lighter) over the years.

For most people all this won’t matter, in practice. It will be the fatigue-reducing Füri ‘reverse wedge’ handle shape (also patented), and innovative blade shapes that make Füri knives their favorite brand.

“My knife blade has uneven scallops – some are closer to the edge than others – does this matter?”

The positioning of the friction-reducing scallops on some Füri knife blades is done by hand, so some uneven placement will occur.  This positioning has no affect whatsoever on performance of the knife, and actually makes your knife a one-of-a-kind Füri product!

SHARPENING INFORMATION

“Can I use the Füri Tech Edge and Ozitech sharpeners on ‘thin convex edge’ Japanese/Santoku knives (eg. Global and Shun)?”

It is a very good idea to ‘convert’ the edges of all your Japanese knives (except chisel-edge sashimi knives) to perfectly flat-sided bevels at 20 degrees each side. The only way to achieve this, with perfect accuracy and a true professional hone, is with Tech Edge or Ozitech sharpening systems. Our extensive research, as mechanical engineers, shows that this edge offers the best combination of edge retention, strength, and sharpness.

Actually, such Japanese brands aren’t a flat wedge all the way to the cutting edge (such a thin edge would be useless in practice: it would constantly chip and fold over): their edges are ‘convex’, or slightly rounded through the last few millimetres. This isn’t a bad edge; it just isn’t as good as an accurately honed flat bevel edge. It will also be almost impossible to maintain exactly this shape using manual Steel or stone methods, so maintaining perfectly shaped 20 degree bevel edges with Tech Edge or Ozitech is certainly preferable.

If using the Tech Edge system, we recommend ‘working backwards’ through the system to ensure minimum metal removal on such thin blades. If the edge is still in reasonably good condition, start with the final (stage 3) Tech Hone stage, and check the edge after 10 swipes. If the edge is sharp, that’s great: no need to remove metal with the coarser stages 2 (Diamond Fingers) and 1 (Edge Restorer). If Tech Hone fingers don’t work, the edge is a bit worn and out of shape, so try 10 swipes on Diamond Fingers. If that works, finish with Tech Hone. If not, try a few swipes at a time through stage 1 Edge Restorer until sharp. Continue through Tech Edge system, and maintain in the normal way (mostly on Tech Hone, per the instructions).

If using Ozitech Diamond Fingers, swipe the blade through 2 times and check for sharpness. Instead of honing as much as possible like you would with Tech Hone, only do one or two swipes every time the edge feels dull. The diamond coating would wear the blade more rapidly if it were used too frequently. The ideal honing device is Füri Tech Hone (our super-fine non-diamond fingers).

“How do I sharpen heavier knives/hunting knives with the Tech Edge Restorer?”

The Tech Edge Restorer also works wonderfully for heavier cooks’ knives and hunting knives.  It’s recommended that the Restorer be bolted to a bench, or mounted in the new Tech Edge bracket, to give the user more leverage and to avoid ‘vibrations’, since there is more metal removal required on knives of this nature.

“Can I sharpen shorter blades on the OZITECH and Tech Edge sharpeners?”

Short blades, down to small folding and pocket knives, are honed just as effectively with OZITECH. The strokes are shorter, but as long as the blade is traveling down and back through at least one finger each side, the same perfect 20 degree bevels, with a real honed finish, will be created as with any longer blades.

“Can I sharpen serrated blades on the OZITECH and Tech Edge sharpeners?”

We certainly recommend maintaining serrated ‘combo’ blades (common in outdoor/sporting knives) with Füri Diamond Fingers (in Ozitech or Tech Edge sharpening systems). The same is true for old steak knives or bread knives with serrations so worn that they don’t cut anymore. The diamonds will sharpen the blade by grinding a small 20 degree bevel on the flat side of the edge, and this is fine for most purposes.

We don’t, however, recommend sharpening expensive forged bread knives on our sharpening systems: it is best if these are maintained with one perfectly flat side, due to the finer cutting tasks they are used for.

“My knives were dull or “blunt” when I first bought them.”

Füri knives are sharpened to high accuracy and professional sharpness at the factory using the Füri Tech Edge sharpening system. Very rarely, an edge may not be fully sharpened on the Tech Edge system, or experience some damage in transit. We recommend first using your sharpening method, preferably Füri Tech Edge or Ozitech to return the edge to full professional sharpness.

If for some reason this does not quickly return your edge to the expected sharpness, please return the knife to your place of purchase for an exchange.

Click here for more detail on sharpening and edge maintenance.

“My Furi knife was initially sharp, but lost its edge quickly and went dull. What happened, and what can I do?”

Thank you for letting us know about the problem you have experienced.

There may be a number of reasons for a knife losing its edge:

• Destroying the sharp edge by cutting on hard surfaces, like glass, marble, stainless steel – common problem.
• Insufficient or incorrect edge maintenance (honing/sharpening) – common problem.
• Incorrect hardness in the knife blade – very rare problem.

The first two are very common, and are easily solved through correct selection of cutting boards (always plastic or rubber synthetics, or wood), and correct edge maintenance. (There is often an incorrect expectation that professional knives have edges that last almost forever, and don't need sharpening, particularly if only household serrated knives have been owned previously.) The last is a very rare error in heat treatment, but not impossible.

Please first review our advice on knife care and sharpening?

If the knife really only requires resharpening, it is important to know how to do this for future satisfaction in owning and using all types of professional knives. A little knowledge and the right tools will save a lot of time and give a lot more cutting pleasure.

If correct sharpening of the edge does not work (the edge quickly becomes dull after proper sharpening and honing), you may indeed have an incorrectly hardened and tempered blade. If that is the case please return the product to your place of purchase for correct procedure for warranty replacement.

“What happens when I eventually sharpen my Füri knife blade down through the scallops – will it create an uneven edge like a serration?”

No, you will still have a full straight edge, because the scallops aren’t ground deep enough to go past the centerline of the blade. See some scalloped ham slicers in cook shops: they often already have the scallop partially over the cutting edge, but the edge is still perfectly straight. The same happens when you sharpen a blade through the scallops – you will still have a straight edge, with no ‘dips’.

“How do I sharpen my serrated (Bread/Utility) knife?”

We would recommend that you don’t use a steel on serrated knives. Technically it is possible, but in practice it will usually ruin the edge.

A professional bread knife shouldn’t need sharpening for many years, in a domestic situation. If the knife does wear eventually, most of the wear will be in the form of ‘rounding’ of the back (flat) side of the teeth.

The best way to sharpen the serration is to remove this ‘rounded’ material by putting the blade down flat on a stone, on the flat side (opposite side to serration grind), and grind back the edge until the teeth are completely flat on this back surface.

If you are not confident with this procedure, we would suggest taking your knife to a professional knife sharpener who will show you the easiest way to sharpen your serrated knife.

The Füri bread knife is probably the longest-wearing Bread knife on the market because the teeth have rounded tops, not the fragile pointed tips of regular serrations.

If your bread knife or steak knife is completely worn down, you can make it sharp again by swiping it through Diamond Fingers (Tech Edge or Ozitech versions). This will put a small 20 degree bevel on the flat side of the blade, but the edge will be sharp and cut again. Over time, the teeth will completely disappear,  and you will have a perfectly good straight-edge knife that you can continue to keep sharp on Füri Diamond Fingers.

“What is the correct angle at which to sharpen the knives?”

Twenty degrees, each side of the blade, is the best angle, if the bevel can be flat all the way to the cutting edge. Mark Henry, Füritechnics Group CEO and Chief Engineer has made this recommendation and he should know: he has spent many years researching not just knives, but the mechanics of cutting edges (including his engineering honours degree project on knife materials and cutting edges, where he examined many types of knife materials with different angles and different edge finishes under a scanning electron microscope, without wear, after 3000 cutting strokes, and after 6000 cutting strokes on a wear testing machine he designed). This research has given Füritechnics a lot of new knowledge about knives and cutting edges, and enabled us to develop patents for unique innovations for chefs. The proof is in the performance of our knives and sharpening tools.

“What is the difference between Steels and Diamond Fingers?”

The Diamond Fingers creates exactly the same edge 'micro serration' as the traditional Diamond Steel. The key difference between the Diamond Fingers and the regular diamond Steel is that the Diamond Fingers creates a very accurate cutting edge bevel of 20° either side of the blade edge and produces very flat sides (not rounded). Diamond Fingers are far superior to a skilled operator of a Steel and Stone, because it produces a technically superior edge (geometry and finish), does it very quickly, and requires no skill.

“Why is the Tech Edge Sharpening System superior to the electric sharpeners available?”

Tech Edge has many benefits over electrical units besides the fact that it doesn’t need electricity, is easy to store, and can be moved anywhere your knives are located. Tech Edge is faster, more accurate, simple to use and delivers a professional fine honed edge. Electric sharpeners normally have to be taken out of cupboards, plugged in, then several stages carefully negotiated so you don’t grind too much off your knife. Tech Edge is more accurate, and produces a true professional edge, not a 'rough ground' edge. One major advantage is in the accuracy of delivering a 20° edge: from stages 1 through to 3 Tech Edge maintains the same 20° angle, and the cutting edge is perfectly flat-sided. Another advantage, and one that no electric or gadget sharpeners can come close to is the perfection of the edge finish. Under the microscope the edge created by the final Tech Hone stage is super-fine, so fine that it looks like it would have to have been machined by a robot.

The Tech Hone finish is also more like honing on a real Steel (but with no human error).  So really for the first time ever there is a sharpening tool that achieves a true professional hone, and a more accurate edge shape than any manual or electrical method can achieve.

“My Diamond Fingers seems to have worn out already”

The crushed industrial diamonds of the fingers are quite coarse and very durable and will last longer than regular diamond-coated Steels. This is because the diamonds are a larger 450 or 500 grit industrial diamond, and not the smaller and more common 600 grit that is used in most diamond steels.

However, like all diamond-coated sharpening tools, the diamonds will gradually become worn, and eventually wear down altogether. How quickly this will happen depends on individual use, however as a guide 5 to 7 years for light household use and 3 to 5 years for heavy household use should be expected. In commercial areas a professional kitchen could go through a set of Diamond Fingers in just 1 to 2 years. However when the fingers are eventually worn, replacement fingers can be easily purchased and the worn fingers can be retained for fine honing of slicing, carving, boning, etc, knives (because the worn fingers then act like smooth Chrome Steels or Tech Hone fingers)

If the Diamond Fingers seem to be losing effectiveness very quickly, it will certainly not be due to the disappearance or complete wear of the diamonds. It will however be due to the diamonds becoming clogged with metal dust. The dark grey deposit on the fingers is super-fine metal 'shavings' from the knives that have been sharpened, which will reduce the effectiveness of the industrial diamonds biting into the steel edge of the blade.

Whenever the fingers become dark and less effective, rinsing the diamond fingers under running water, and rubbing over the grey area with a soft brush can wash out the metal dust. The fingers will become shiny, like new, and sharpening effectiveness will be restored.

“My Tech Hone Fingers seem to be losing effectiveness—what should I do about this?”

Even if the Tech Hone fingers have had heavy use (5 or 6 times every day) the fingers should still be okay to use. It is recommend that the Tech Hone fingers be periodically washed thoroughly in warm soapy water and given a scrub to ensure there is no metal dust trapped in the scratched surface of the fingers. This is good maintenance for Tech Hone or Diamond Fingers: often the fingers seem to be worn out, but are really only clogged up with metal dust (just like traditional stones that need similar maintenance).