About aluminium products

About aluminium products

What are the distinctive characteristics of aluminum items?


They are distinguished above all by their excellent heat conductivity and lightness.

Heat spreads rapidly, cooking the food quickly; and they are light, so they are easy to use. Moreover, when aluminum items are eventually disposed of, they are the flag-bearers of recycling, being reduced and reused as raw materials for the next item. We can say that aluminum is a precious metal when considering resource conservation and the environment.

Nevertheless, aluminum also rusts. Having said this, it does not mean that it turns reddish brown like iron. Instead, it shows symptoms of “corrosion”: the appearance of a white powder, blackening and, eventually, holes. The aluminum items which are usually sold include both those with the aluminum material left as it is, and those which have been given alumite treatment. It is important to take note of this because untreated aluminum items and those given alumite treatment need to be cared for in different ways.


What is alumite?


It is a registered trademark given to the treatment process by a Japanese manufacturer.

When aluminum is exposed to the air, a thin oxide layer forms on the surface. This layer protects the surface of the aluminum and prevents corruption. However, unlike the layer on stainless steel, this oxide layer is not strong, and is easily damaged. Therefore, this layer has been artificially thickened and strengthened, and given the name “anodic oxide layer”. The inventor of this treatment process was Japanese.

In alumite treatment, aluminum items are first placed in an electrolytic solution on the anode side, and a lead or carbon plate is placed on the cathode side. Electricity is passed through the solution, creating a thick, strong layer of aluminum oxide on the surface of the aluminum. Next, the countless microscopic pores in this layer are sealed (by carrying out the treatment in steam at high temperature and pressure, or in hot water, and making the layer absorb moisture, its volume expands and the pores are closed). In this way, it is possible to create an extremely hard, heat-resistant surface, and to be very effective in preventing corrosion.

In other words

alumite treatment refers to items which have received “a special treatment protecting the aluminum material from corruption”!


How should I care for aluminum items?

Please take careful note of whether or not your aluminum items have been given alumite treatment, as this affects how to care for them (please see the item “Surface treatment” on the care label to check whether or not they have an alumite coating).


It is important not to damage alumite, so please avoid using steel scourers, cleansers, or anything else which could easily damage it. However thick and strong it may be, it can be damaged.

After you have used the items for a long time, the alumite coating gets thinner, so food may burn and stick to them. Do not scrape it away with a knife; it is important to soak it in warm or cold water until it softens, and then carefully wash it away with a sponge.


If the aluminum blackens or burnt food gets stuck, it is fine to scrub it away with a steel scourer or cleanser. If you instead leave it as it is, this spot will become a source of corruption, and you may end up with holes.


The inside of my aluminum pan has turned black!


When you use an aluminum pan for a long time, a “blackening phenomenon” occurs on the inner surface.

When you use an aluminum pan for a long time, the inner surface may turn black; this is called a “blackening phenomenon”. The main cause is an oxidation reaction between aluminum and water, with the oxide adhering to the surface. This substance reacts in complex ways with impurities in the water, turns black in color and becomes firmly fixed on the surface of the aluminum. For this reason, alumite-treated pans do not easily blacken (of course, if the alumite is damaged or comes off, they will blacken).

If it turns black

First, remove the blackened surface with cleanser or scourer. Next, put rice bran into some water and boil it for around 10 to 15 minutes. A layer similar to alumite will form, and the pan will be less likely to blacken.

Nevertheless, the above method is inferior to alumite, so it is advisable to carry it out frequently. Of course, the blackened part is in no way harmful to humans.


What is the “fluorine resin processing” that we hear a lot about?


It is a kind of processing which makes ingredients less likely to stick or burn onto pans.

Aluminum pots whose inner surfaces have undergone “fluorine resin processing” are the norm these days. Since ingredients are less likely to stick or burn onto them, they are distinguished by the ease with which they can be used for cooking and by the small amount of oil needed in comparison with pans made of other materials. Only a little oil is needed, but if you do not use any at all, the ingredients will burn. Particularly when you first use a pan, it is a good idea to pour a tablespoonful of oil onto a piece of absorbent kitchen towel and wipe the pan with this, then leave the oil to blend in for a little while before use.

fluorine resin processing
fluorine resin processing

For pans treated with fluorine resin, the fluorine resin layer added to the inner surface is everything. This layer is simply a coating on the aluminum material, so a drawback is that it comes off easily.

Recently, items which have been treated to make the layer less likely to come off have started to appear, but as you use them, the layer does eventually come off. The fluorine layer is extremely susceptible to damage and, once damaged, starts to come off from that place, making the pan unusable (this does not mean that it is completely unusable, but it is highly likely that the detached parts of this layer will become mixed in with the food, so we do not recommend it).


What can I do to stop the fluorine resin coming off?

  1. When cooking, avoid metal tools, and use wood or heat-resistant resin tools.
  2. Please avoid prolonged heating of an empty pan or cooking at high temperatures, as these are also causes of damage to the resin.
  3. After use, gently rub the surface with liquid detergent and a soft item such as a sponge in order to remove the dirt.