Introduction of Flying Eagle Electric Bean Grinder modified Precision Machining flat Cutter head single Product Bean Grinder

[material]: SUS420 tool stainless steel (one set of two pieces)

Hardness: HRC55-58 Rockwell hardness

[ruler inch]: 59.50mm*7.80mm

[indexing]: coarse blade 360apper 12, fine blade 360apace 56

[longevity]: above 500kg

[grinding speed]: 1s=4.5-5g

[applicable models]: Tiamo700S, Little Eagle 600N, Zhengyuangxing M520 and all versions of Little Flying Eagle in China.

Preface

ROSE CAFE every day there are individual enthusiasts ask questions about the degree of grinding, in fact, coffee grinding is a complex problem, complex test data for general coffee lovers may be difficult to distinguish, knife shape, angle design; knife tooth depth, length and coarse tooth and fine tooth powder discharge speed; different grinding degree of uniformity; the percentage of ultra-fine powder and ultra-coarse powder percentage; finally, we are concerned about calorific value and other issues.

Knife type: at present, there are flat cutter head, tapered cutter head, ghost tooth cutter head in the market, and other special knife types are invariable, all derived from the modification or combination of the above several kinds of knives. Friends in the coffee industry have different opinions on the above three types of knives. Because the first two types of knives can be produced by precision processing, they can technically produce professional cutters with smooth surfaces, sharp edges and extremely hard materials.

Rose family modified cutterhead size standard 59.5

Material: both flat cutter head and conical cutter head can be produced by precision machining, with a wide range of basic materials, heat treatment and hardening, and anti-oxidation treatment on the surface. Because the special shape design of ghost tooth cutter can only be produced by casting, it is difficult to be machined twice, the dimensional precision is not high, and the surface is very rough, so the hardening of heat treatment will lead to the loss of deformation, so it is difficult to see the sharp blade, and the hardness is only the level of ordinary cast iron. Rockwell hardness tester can not even be tested. American GCS uses 304stainless steel casting to produce ghost tooth cutter head, because it can not be hardened. The hardness is not high. Of course, flat cutter head and cone cutter head for professional and cost control, there are also casting molding, and now there are powder industrial ceramic materials, some low-cost bean grinders use powder metallurgy once molding, and even food safety can not be guaranteed.

The 59.5 knife plate on the market

Hardness: we usually use Rockwell hardness tester to test the average hardness of cutter head steel. General enthusiasts do not have professional equipment. When two knives are suspended and collided, the more crisp the sound, the higher the hardness.

The original cutterhead before modification

The flat cutterhead of ROSE CAFE is made of sus420 martensitic stainless steel hardened by mechanical precision machining. the surface is twice passivated, the oxidation resistance is extremely strong and can be washed with water, and the average hardness can reach HRC55-58. Many professional cutterheads produced in Italy and Germany can reach HRC60-62, but because the mold steel is used with poor rust and oxidation resistance, it is generally treated with oil absorption and anticorrosion, which is difficult to meet the requirements of food safety. The higher hardness does not help much, because HRC55 can already be used as a tool material for processing ordinary steel, and the hardness of coffee beans is of course not a problem.

After retrofitting the Rose knife head

Professional cutters usually have a life span of more than 500kg. Imported cutters with titanium alloy plating tools are actually mainly used for industrial mass grinding. Let's calculate that if household consumes 100g coffee beans a day * 365 days a year, grinding 36.5kg for 10 years, but 365kg for 10 years, and few people can consume 100g coffee beans a day, so the life of professional cutters is basically not considered by household and ordinary shopkeepers. It is not necessary to buy an expensive titanium-plated cutter head.

Ultra-fine powder: the Italian industry has a technical standard for the cutterhead. We only talk about the fine powder index. The fine powder referred to in the Italian standard refers to the visible particles with a diameter below 0.3mm. Of course, this standard is based on the Italian grinder. As a single product, the ultra-fine powder that really slows down the flow rate. I think it is an ultra-fine powder with a diameter below 0.1mm or even more small and indistinguishable to the naked eye. This kind of powder is especially obvious when it is flushed by hand and will be adsorbed on the inner surface of the filter paper. the increase of the number of micro-powder will cause the blockage of micropores on the filter paper surface, decrease the flow rate, prolong the extraction time, and over-extract coffee.

Reasonable knife shape, processing precision, powder discharge speed and sharpness of the cutter head determine the amount of ultra-fine powder. When the average grinding particles are about 0.5mm, the flat cutter head of ROSE CAFE can still ensure a smooth flow during hand flushing. 20g powder can complete the extraction of 1: 10 in no more than 1 minute and 30 seconds. At this time, because the particles are small, the concentration is high, but there is no miscellaneous smell, it is not sour and bitter, and can be mixed with water to a suitable concentration for everyone. Of course, it is recommended that you grind the particles with an average diameter of 1mm when hand-punching, and 0.5mm particles are only used as the standard of limit test.

Evenness: in fact, with the current technology, it is very difficult to achieve coffee grinding that is completely uniform in particle size. in actual tests, we found that in the production of hand-brewed coffee and other products, really uniform coffee does not bring distinct layers. the delicious coffee with explosive aroma becomes thin in taste and over-clean in flavor, and finally we give up the knife-shaped scheme that is too uniform.

After repeated tests, we found that when grinding a single product, as long as we ensure that the number of coffee particles 0.3mm, 0.5mm, 0.5mm, 0.5mm, 0.8mm, and 0.8-1.3mm is within a certain proportion, and as long as the number of ultra-fine powder can be reduced as much as possible, the extracted coffee has a full taste, explosive aroma and a clearer sense of hierarchy. After the completion of hand-washing, observing the surface of the filtered coffee powder and filter paper, it is found that the uniformity is high with the naked eye, and there is very little fine powder left on the surface of the filter paper, so I hope everyone will not enter the misunderstanding that the more uniform the better.

Calorific value: in the past, we found that there will be a temperature rise in coffee knife grinding, and the temperature rise will lead to the loss of coffee aroma. It is believed that the temperature rise is related to the rotational speed of the motor. The higher the speed, the higher the temperature. The actual test found that this statement is very one-sided.

Coffee grinding heat must be caused by friction and cutting. in fact, the speed of the motor used in the bean grinder is only about 3000 revolutions per minute. The real reason for the temperature rise is that the cutting edge is not sharp, and the coffee is smashed rather than chopped. We all know that it takes no effort to cut vegetables with a sharp knife. On the contrary, it takes time and effort. The greater the resistance, the greater the friction, the more obvious the temperature rise. The powder discharge design of the coffee cutter is also the key, if the ground coffee can not be discharged in time in the gap between the cutters, it can also cause excess friction, of course, the temperature rise will increase, and the ultra-fine powder will also increase.

In addition, we make a maximum of 30g each time, even if the powder discharge is not smooth, the props are not sharp enough, ignoring the problem of uniform and fine powder, 30g of beans is actually very difficult to cause the problem of knife head temperature rise. I hope everyone will not get into misunderstanding. The test data of ROSE CAFE refitted cutter head is 4.5-5g per second, which means that 30g coffee beans only take 6-7 seconds, because the feeding speed of different machines is slightly different. The maximum length of 30g is no more than 8 seconds.

Noise: many people think that the noise of the coffee grinder is very loud, and the noise source of the grinder is the concentricity and dynamic balance of the motor itself, as well as the excessive vibration and friction caused by the size error of springs or other parts, which exist when idling, and the highest noise is actually when coffee is ground.

Dull coffee cutter can cause unnecessary noise, can not discharge powder in time can also form noise, on the contrary, the sharper the knife, the smaller the friction, the smaller the noise, the faster the powder discharge, the shorter the noise time. The modified knife of ROSE CAFE can effectively reduce noise because of its fast powder discharge and sharp edge.

Degree of grinding: after modification, the small flying eagle is the most common to sloshing, the size of the fuselage is also relatively regular, and the price is moderate, so it is recommended to use the small flying eagle that is sloshing. Due to the thickness of the cutter head, the scale needs to be re-adjusted to zero. Unscrew the cross hole screw in the center of the scale knob, and you can see that the black parts with screw teeth and teeth are tightened to the left, so there is no need to be too tight. Align the position of the scale knob stop with the arrow in the middle of the fuselage into the clip position and screw.

After zero completion, we recommend 4-4.5 for the forward swinging Little Eagle hand stroke scale. Siphon kettle, French pressure kettle and Ella pressure can use a scale of 4.5-5. The latter can be understood as a coarse scale for a long soaking time and a fine scale for a short time.