Pujadas Pots Guide

THE GUIDEBOOK OF PROFESSIONAL COOKWARE

DRAFTING AND COORDINATION

DANIEL SOLER

TEXT

TONI JIMÉNEZ / PERE CASTELLS / DAVIDE CASSI / MARTIN LIPPO

DESIGN TWOELF

PHOTOGRAPHY

ELISABET ARMORA / BERNAT JOVAL / OV PRODUCCIONS

IMAGE GALLERIES

UNSPLASH / PEXELS /PIXABAY / VISUALHUNT

PRINTING MONTSENY COMUNICACIÓ

ACKNOWLEDGEMENTS

JESÚS PLANCHART / JOAN ROCA / CELLER DE CAN ROCA / VAKUUM / SCIENCE & COOKING WORLD CONGRESS / COCINA HERMANOS TORRES

AND OF COURSE, THE WHOLE TEAM AT VOLLRATH PUJADAS.

LEGAL DEPOSIT

GI 1476-2019

1st edition: September, 2019

© VOLLRATH PUJADAS, S.A.U., Santa Coloma de Farners (Girona). September 2019.

All rights reserved. VOLLRATH PUJADAS, S.A.U. is the owner of all intellectual and industrial property rights contained in this publication, all rights being expressly reserved. Similarly, the reproduction, transformation, distribution and public communication of all or part of the content of this publication, with or without profit, in any medium and by any means, are expressly prohibited without the prior and express written permission of VOLLRATH PUJADAS, S.A.U.

“

In the field of gastronomy, the creation of knowledge in order to improve technical applications and to make advances is the great challenge for the future. This book is significant for precisely this aspect. The importance of knowing how materials and their forms behave when used in cookware is vital. New generations need this information in order to meet the future challenges in cooking.”

PERE CASTELLS

Science and Cooking Barcelona

“

The varied range of utensils that we currently have at our disposal makes most of the tasks in the kitchen easy for us. But it is by learning to make the most of these utensils that we can fine-tune our techniques and expand the range of possibilities in the kitchen. Knowledge is important. Without it, having the huge range utensils available on the market, or the latest model of each machine, or the latest processing or cooking method we decide to carry out, is useless.”

JOAN ROCA

Celler de Can Roca

STRUCTURES AND FORMS IN COOKING

STRUCTURES FORMS

COOKING

STOCK POTS

COOKING POTS

PAELLA PANS

FRYING PANS

SAUTÉ PANS

SAUCE PANS

WOKS

COOKING, HEAT AND TEMPERATURE

INTRODUCTION

THE EVOLUTION OF COOKING FROM THE DISCOVERY OF FIRE

FROM TIME IMMEMORIAL, COOKING HAS GONE HAND-INHAND WITH FIRE. AND IN FACT, FIRE AND COOKING HAVE ALWAYS BEEN ALMOST SYNONYMOUS CONCEPTS. MANY ARCHAEOLOGICAL SITES HAVE BEEN INVESTIGATED WHERE VARIOUS FIRE STRUCTURES HAVE BEEN FOUND. THESE STRUCTURES REFLECT THE VARIED SOCIAL ROLES IN NEANDERTHAL HOUSEHOLDS THAT HAVE BEEN DISCOVERED IN CAVES DATING BACK TO OVER 50,000 YEARS.

THE EVOLUTION OF COOKING FROM THE DISCOVERY OF FIRE

About 5,000 years ago, Egyptians and Babylonians introduced a new concept: cooking in a stone oven, which allowed food to be cooked from both above and below at the same time.

Everything continued along similar lines virtually until the industrial revolution. At the end of the eighteenth century, the popular “economic cooking appliance” was born, made of cast iron, heated using firewood or coal. An upper cooking surface allowed several foodstuffs to be cooked simultaneously, while at the same time the kitchen oven was introduced.

In 1802, in an attempt to popularize the cooker, inventor Frederic Albert Winson presented the first gastronomic creation prepared with a gas cooker. He wanted to illustrate the possibilities that such cookers offered, such as the ease of turning them on and off, as well as improvements in hygiene.

But inefficiencies and dangers meant gas cookers didn’t become widespread until the mid-19th century, though gas is now one of the most widely used energy sources in both professional and domestic kitchens.

Later, with the arrival of electricity, this was also seen as a possible means for generating heat. In 1890, the first electric stoves appeared, equipped with thermostats. These rudimentary appliances didn’t regulate the heat very well and caused a certain amount of disappointment when problems with cooking occurred: the food was either raw or burnt. It’s time had yet to come.

In the twentieth century, the electric oven was presented at the World Fair in Paris, but again, the lack of efficient regulation meant that ovens with genuine thermal control weren’t commercially sold until 1935.

In the 1950s, electric-operated cast iron plates and coil stoves were available, precursors of the vitroceramic hob, and which by the end of the twentieth century already gained considerable market penetration.

INDUCTION COOKING TECHNOLOGY: THE FUTURE PERFECTION OF TEMPERATURE AND TIME CONTROL.

The first trials in induction cooking can be placed around the middle of the twentieth century, when General Motors carried out demonstrations, heating water while placing a piece of paper between the vessel and the induction plate, but it largely remained a curiosity. In 1971, at a convention in Houston, Westinghouse introduced a product for domestic use, and as a result, they began to produce the first con-

sumer hobs for homes. The price was very high which limited the expansion of the product. In 1979, induction plates appeared in Europe at the domestic level. It was in France that the Scholtes Company presented a hob, based on magnetic field activity, which allowed the heat intensity to be controlled.

NEANDERTHALS USED FIRE AS A COOKING TOOL.

THE EGYPTIANS AND BABYLONIANS INTRODUCED COOKING IN A STONE OVEN.

INDUSTRIAL REVOLUTION GIVES PLACE TO THE FIRST ECONOMIC KITCHENS.

THE FIRST ELECTRIC COOKING RINGS ARE BORN.

TODAY 1950

COOKING RINGS AND OVENS WITH THERMAL CONTROL MAKE HEADWAY IN THE MARKET, THE PRECURSORS OF THE HOB.

1980

DOMESTIC INDUCTION HOBS APPEAR ON THE MARKET

TODAY, GAS AND ELECTRIC COOKERS LIVE ALONGSIDE INDUCTION HOBS.

INTRODUCTION TO THE MATERIALS

THE MOST SUITABLE MATERIALS FOR CONSTRUCTING COOKING VESSELS ARE ALWAYS THOSE ARE IMPERMEABLE AND UNDOUBTEDLY, GOOD CONDUCTORS OF HEAT, BUT WHICH DO NOT CONTAMINATE FOOD. THESE TWO CHARACTERISTICS ARE NOT FOUND TOGETHER IN ANY TYPE OF MATERIAL USED FOR THE CONSTRUCTION OF COOKWARE.

AND TO COMPLICATE MATTERS FURTHER, WE SHOULD ALSO ADD AN ADDITIONAL CONDITION: WE DEMAND THAT THEY ALSO HAVE A GOOD MECHANICAL RESISTANCE

TO IMPACT (THAT THEY DON’T BREAK OR BECOME MISSHAPEN EASILY). FOR EXAMPLE, WHEN AN OVEN TRAY IS NO LONGER FLAT, IT CREATES A NON-UNIFORM THICKNESSES IN THE LIQUID, PRODUCING UNEVEN COOKING. OR, FOR EXAMPLE, THE DEFORMED BASE OF A POT REDUCES THE SURFACE AREA IN CONTACT WITH THE HOB, MAKING HEAT TRANSMISSION EXTREMELY INEFFICIENT.

TAKING THESE FACTORS INTO ACCOUNT, WE CAN LOOK AT THE MATERIALS MOST COMMONLY USED IN THE KITCHEN AND SEE HOW THESE PROBLEMS ARE RESOLVED IN PRACTICE.

Metals and alloys

Non-metallic mineral materials

WE FIRST MUST DISTINGUISH THE THREE MAIN CATEGORIES:

Polymeric materials

The most commonly used metals and alloys for the manufacture of kitchen utensils have been copper, iron, aluminium and stainless steel. Some of these have practically disappeared from use and others have become more widespread.

The non-metallic solid materials are characterised by a low thermal conductivity, the most common are plastic, ceramic and glass materials, where the different structures provide a variety of mechanical properties, ranging from the fragility of the glass and ceramics up to the extreme resistance of silicone.

MATERIALS

IN COOKWARE AND KITCHEN UTENSILS

IN THE WORLD OF COOKWARE, WE CAN FIND A WIDE RANGE OF MATERIALS. EACH OF THESE MATERIALS IS THE RESULT OF A SPECIFIC CULINARY NEED AND HAS A SERIES OF ADVANTAGES AND LIMITATIONS. WHEN USING THEM, WE MUST CONSIDER WHAT MATERIAL WILL GIVE US THE DESIRED RESULT. IN ADDITION TO ITS USE, OTHER ASPECTS TO BE TAKEN INTO ACCOUNT INCLUDE MAINTENANCE, THE OPTIMAL SIZE, THERMAL CONDUCTIVITY AND PRICE.

What is it...?

*Thermal conductivity is the ability of a material to transmit heat by direct contact. The higher the value, the faster the temperature is transferred throughout the body of the material.

*Specific heat capacity is the amount of energy a material needs to increase its temperature by 1°C. Using this, we can say that the higher the value, the more energy (kCal) we will have to apply in order to increase the temperature.

MATERIALS

Below we will discuss the materials that can be used in the manufacture of cookware.

SILVER

COPPER

MATERIAL: HEAVY

THERMAL CONDUCTIVITY: EXCELLENT COST: HIGH

P. 24

IRON

MATERIAL: HEAVY

THERMAL CONDUCTIVITY: LOW

COST: LOW

P. 28

ALUMINIUM

MATERIAL: LIGHT

THERMAL CONDUCTIVITY: MEDIUM COST: LOW

P. 34

STAINLESS STEEL

MATERIAL: HEAVY

THERMAL CONDUCTIVITY: LOW COST: HIGH

P. 38

MULTI-METAL

MATERIAL: HEAVY

THERMAL CONDUCTIVITY: MEDIUM7 HIGH COST: HIGH

P. 42

CLAY

MATERIAL: LIGHT

THERMAL CONDUCTIVITY: VERY LOW COST: LOW

P. 46

GLASS

MATERIAL: LIGHT

THERMAL CONDUCTIVITY: VERY LOW

COST: LOW

P. 50

COPPER

COPPER WAS THE FIRST METAL USED FOR THE MANUFACTURE OF COOKING VESSELS LARGELY DUE TO ITS MALLEABILITY. IN THE ROMAN ERA, IT WAS MAINLY OBTAINED FROM CYPRUS, WHICH GIVES ITS NAME TO THE METAL (FROM LATIN: CUPRUM) AND EVOLVING INTO THE NAME WE USE TODAY “COPPER”.

COPPER IS ONE OF THE FEW NOBLE METALS THAT CAN BE FOUND IN NATURE USED WITHOUT PRIOR TREATMENT. THUS IT WAS THE FIRST METAL THAT WAS USED TO MANUFACTURE KITCHEN UTENSILS. IT IS THE HEAVIEST, THE MOST EXPENSIVE AND ONE OF THE BEST CONDUCTORS OF HEAT.

UNFORTUNATELY, IT IS ALSO VERY REACTIVE IN AIR. IT OXIDIZES EASILY, FORMING A GREY-GREEN PATINA THAT CAN EASILY BECOME VERY TOXIC AND EASILY CONTAMINATE FOOD.

DUE TO THE PROBLEMS OF TOXICITY AND THE HIGH COST OF BOTH MAINTENANCE AND PURCHASE, THE USE OF COOKING VESSELS MANUFACTURED FROM COPPER HAS BEEN REDUCED TO A MINIMAL LEVEL, EVEN THOUGH WE CAN OCCASIONALLY FIND THEM IN THE WORLD OF PATISSERIE OR DECORATION.

In order to prevent or delay the oxidation process, copper vessels are usually coated on the inside with a thin layer of a much less reactive metal, namely tin. However, tin is very delicate and, with wear, the layer becomes thinner and ends up being completely worn away at some points. It also melts at 232°C, usually lower than the temperature of the flame or hob. When the vessel is full it is unlikely to reach this temperature as the food would burn first, but with an empty container it is very easy for the tin liner to melt as a result of the high temperature. Therefore, it is recommended that you never place empty, coated copper containers in direct contact with the heat source.

However, because of its high thermal conductivity, copper is the most suitable material when very fast temperature variations are required, in particular rapid cooling in order to stop cooking. Typically, this would apply when heating sugar.

Did you know that?

To clean the outside of uncoated copper items, you should make up a solution of 100g of water with 20g of white vinegar and a tablespoon of baking soda. This solution can be used to clean the outside, as long as it hasn’t been finished with some type of varnish. If this is the case, the manufacturer’s instructions should be followed.

MATERIAL: VERY HIGH WEIGHT. MOLDABLE, BUT VERY OXIDIZABLE.

THERMAL CONDUCTIVITY: EVEN HEAT DISTRIBUTION THROUGHOUT THE RECEPTACLE

USE: SUITABLE FOR GAS AND ELECTRIC COOKERS. IDEAL FOR COOKING WHERE PRECISE TEMPERATURE CONTROL IS REQUIRED.

MAINTENANCE AND HYGIENE: CLEANING WITH NEUTRAL SOAPS AND NON-ABRASIVE SPONGES. NOT SUITABLE FOR DISHWASHERS. WHERE FOOD HAS STUCK TO THE VESSEL, LEAVE TO SOAK IN A MIXTURE OF WHITE-WINE VINEGAR AND LEMON.

Fe

HISTORICALLY, IRON FOLLOWED COPPER IN THE DEVELOPMENT OF COOKING MATERIALS. IN COMPARISON WITH COPPER, IT HAS A HIGHER SPECIFIC HEAT CAPACITY AND A LOWER THERMAL CONDUCTIVITY. THESE CHARACTERISTICS ARE IDEAL FOR ACHIEVING AND MAINTAINING VERY HIGH TEMPERATURES.

UNFORTUNATELY, CHEMICALLY, IRON HAS NO BENEFICIAL CHARACTERISTICS. IT IS A HYGROSCOPIC MATERIAL (IT EASILY ABSORBS ATMOSPHERIC HUMIDITY) AND, IN CONTACT WITH AIR, IT PRODUCES OXIDES (RUST) WHICH CORRODE THE MATERIAL.

MATERIAL: VERY HEAVY. HIGHLY VULNERABLE TO CORROSION (OXIDATION).

THERMAL CONDUCTIVITY: NOT VERY GOOD (LONG DELAY TO ACHIEVE THE DESIRED TEMPERATURE), HOWEVER IT MAKES A MAINTAINS A VERY STABLE TEMPERATURE FOR LONG-DURATION COOKING.

USE: SUITABLE FOR GAS, ELECTRIC, INDUCTION AND OVEN.

MAINTENANCE AND HYGIENE: BEFORE USING FOR THE FIRST TIME, IT IS ADVISABLE TO COOK SOMETHING IN THE ITEM THAT CAN BE DISCARDED. THIS WILL ALLOW THE INITIAL IMPURITIES IN THE RECEPTACLE TO BE CLEANED.

Did you know that?

-The item should be heated before use.

-Food should not be stored in the receptacle after cooking.

-It is recommended to clean with soap-free water, dry and coat with a thin layer of oil before storing in a dry place. This will delay or prevent the oxidation process, keeping its properties in optimal condition.

- Washing in a dishwasher is highly discouraged.

CAST IRON

Cast iron is not a metal, but an alloy composed of iron (Fe) and carbon (C) in high percentages (between 2.11% and 6.67%, which is the maximum limit of solubility of carbon in iron).

Cast iron, compared to iron, has higher mechanical strength, a higher specific heat capacity and lower thermal conductivity. Therefore, it is able to maintain higher and more stable cooking temperatures than iron. In some cases, these temperatures are too high for certain types of cooking. For this reason, iron is preferred for delicate cooking, while cast iron is widely used in the production of hobs and griddles.

From a chemical point of view, it presents the same problems as iron and is subjected to the same treatment.

Traditionally, to avoid rapid oxidation, iron items designed for cooking go through a curing process. This involves covering the entire surface of the receptacle (both inside and outside) with a layer of grease or oil and subjecting it to a high-temperature process, creating a protective layer that will penetrate the pores, making it impermeable when hot, and will polymerize,

forming a non-stick layer similar to the latest polymer coatings.

Over time, a stable black oxide is created beneath the polymerized layer that has excellent protective properties. However, during the initial period of use, it is a good idea to treat the ferrous receptacle carefully as the polymer layer is quite delicate. The use of metal or abrasive sponges and aggressive detergents should be avoided.

MAINTENANCE

Fine salt is used for cleaning. Until the interior becomes blackened, it is advisable to oil it frequently and avoid cooking acidic foods. Particularly in the past, the inside of iron pans was often enamelled. However, these enamel layers are not very resistant to wear or sudden changes in temperature and tend to deteriorate over time.

ALUMINIUM

ALUMINIUM IS A CHEMICAL ELEMENT WITH THE SYMBOL AI, WHICH IS VERY ABUNDANT IN THE EARTH’S CRUST, CONSTITUTING 7.3% OF ITS MASS.

IT IS A VERY SOFT, MALLEABLE, NON-MAGNETIC METAL WITH A VERY GOOD THERMAL CONDUCTIVITY. IT IS THE CHEAPEST AND THE LIGHTEST OF THE METALS USED FOR THE MANUFACTURE OF KITCHEN UTENSILS. IN CONTACT WITH AIR, A THIN LAYER OF OXIDE FORMS, WHICH ADHERES VERY WELL TO THE METAL AND IS EQUIPPED WITH EXCELLENT ANTI-STICK PROPERTIES. THE DOWNSIDE IS THAT THIS PATINA IS VERY THIN AND CAN BE EASILY SCRATCHED. TO OBTAIN A THICKER OXIDE LAYER, SOMETIMES ALUMINIUM IS SUBJECT TO THE ANODIZATION PROCESS.

Did you know that?

Due to its low density, its specific heat capacity is lower than that of other metals, so a thicker base is required to maintain stable cooking temperatures. In addition, aluminium, especially where it is thin, can easily harden.

Al

MATERIAL: EXTREMELY LIGHT AND VERY MALLEABLE. THESE FEATURES MEAN IT IS NOT VERY RESISTANT TO KNOCKS AS IT DEFORMS VERY EASILY. IT IS A POROUS MATERIAL THAT CAN MAKE CLEANING DIFFICULT.

THERMAL CONDUCTIVITY: AFTER COPPER, ALUMINIUM IS THE MATERIAL WITH THE HIGHEST HEAT CONDUCTIVITY USED FOR THE MANUFACTURE OF COOKWARE. THIS MEANS WE CAN GET A VERY UNIFORM HEAT DISTRIBUTION THROUGHOUT THE RECEPTACLE AND MAKES IT THE IDEAL MATERIAL FOR ENERGY SAVING.

USE: IDEAL FOR GAS OR ELECTRIC KITCHEN. NOT APPROVED FOR INDUCTION UNLESS IT HAS AN IRON BASE SOLDERED TO THE EXTERNAL PART OF THE BOTTOM. IT CAN BE USED IN THE OVEN WITHOUT PROBLEMS.

MAINTENANCE AND HYGIENE: BEING A POROUS MATERIAL MEANS THAT CLEANING IS MORE COMPLICATED BECAUSE, IF IT IS NOT DONE CORRECTLY, BACTERIA MAY REMAIN IN THE PORES AND CONTAMINATE THE FOOD.

Did you know that?

-Due to its porosity, food must not be stored in aluminium receptacles.

- It should be cleaned with neutral soaps and non-abrasive sponges.

- It is not recommended to use in the dishwasher, as it may soil the surface of the piece, causing it to adopt a whitish colour.

Ai

STAINLESS STEEL

THIS IS AN ALLOY OF IRON (FE) AND CARBON (C), WITH A PERCENTAGE OF CARBON LOWER THAN 2.06%. THE RESULTING METAL HAS BETTER MECHANICAL PROPERTIES THAN IRON, BUT IS STILL VULNERABLE TO OXIDATION.

THE ADDITION OF CHROMIUM (CR) TO THE STEEL, AT A PERCENTAGE OF BETWEEN 11 AND 18%, INHIBITS IRON OXIDATION, MAKING THE STEEL STAINLESS.

MARTENSITC FERRITIC

CORROSION RESISTANCE: LOW

MAGNETIC: YES

AISI - SERIES: 403-410-416-420-42-431-440

CHROME.: 10.5%-18%

CARBON: UP TO 1.2%

NICKEL: 0

AUSTENÍTICOS

CORROSION RESISTANCE: EXCELENTE

MAGNETIC: NO*

AISI - SERIES: 301-303-304-309-310-316-321

CHROME.:16%- 18%

CARBON: 0.03% - 0.08%

NICKEL: 8% - 12%

CORROSION RESISTANCE: MEDIA

MAGNETIC: YES

AISI - SERIES: 406-409-430-434-436

CHROME.: 10%-18%

CARBON: UP TO 0.08%

NICKEL: 0

AUSTENÍTICOS

CORROSION RESISTANCE: EXCELENTE

MAGNETIC: NO*

AISI - SERIES: 201

CHROME.: 16%- 17%

CARBON: 0.10%

NICKEL: 3.5% - 4.5%

*It acquires a certain magnetism once transformed.

% of the steel number in bold.

If we add nickel (Ni) to this alloy of iron, carbon and chromium at a percentage of between 8 and 10%, allowing this new alloy to become malleable, it can be moulded and consequently used to manufacture deep containers. The combination of these chemical elements (18% Cr + 10% Ni) to the iron and carbon alloy, gives us what is commonly referred to as 18/10 STAINLESS STEEL, surgical steel or, by the American Iron and Steel Institute, AISI 304, the most commonly used material currently used in the manufacture of kitchen furniture and cooking utensils at a professional level.

This alloy, with a high chemical stability against oxidation, has low thermal conductivity, half that of cast iron at best, which is too low to guarantee a uniform heating of a steel base over a heat source.

To compensate for this low thermal conductivity, stainless steel vessels designed for the preparation of food through heating are equipped with what is known as a thermal diffusing or sandwich base, in order to facilitate the transmission of heat throughout the body of the vessel.

MATERIAL: HIGH RESISTANCE TO IMPACT, MAINTAINING A PERFECT PHYSICAL APPEARANCE.

THERMAL CONDUCTIVITY: THIS MATERIAL DOES NOT BENEFIT FROM A HIGH DEGREE OF THERMAL CONDUCTIVITY, BUT WITH THE ADDITION OF A THERMAL DIFFUSING BASE, IT ALLOWS THE HEAT DISTRIBUTION THROUGHOUT THE BODY OF THE RECEPTACLE TO BE MUCH MORE EFFICIENT.

USE: SUITABLE FOR ANY HEAT SOURCE: GAS, VITROCERAMIC, OVEN (PROVIDED IT DOES NOT HAVE HANDLES MADE OF WOOD, PLASTIC OR OTHER MATERIALS NOT RESISTANT TO HIGH TEMPERATURES) AND INDUCTION (AS LONG AS THE RECEPTACLE HAS A THERMAL DIFFUSING BASE CONSTRUCTED WITH A FERROUS STEEL PLATE ON THE BOTTOM).

MAINTENANCE AND HYGIENE: NOT POROUS, WHICH AIDS CLEANLINESS. FOOD REMAINS MAY ADHERE TO THE BODY OF THE RECEPTACLE.

DO NOT USE BLEACH OR ALKALINE DETERGENTS, AS THESE CAN DAMAGE THE MATERIAL. IT IS ADVISABLE TO USE NEUTRAL SOAP.

Do you know that?

- In order to maintain the cookware’s appearance, especially if it has a non-stick coating, it is important not to use scouring pads or metal utensils as these will scratch the item. To keep the nonstick coating in good condition it is also advisable not to exceed temperatures above 220°C.

- They are not recommended for storing very acidic foods, such as tomato sauces or seafood. These can cause micro-perforations in the steel, making the receptacle irretrievably unusable.

- Suitable for dishwasher use, except for those that have a non-stick surface. Do not leave the empty item on a heat source and avoid thermal shocks.

Do not subject items to sudden cooling.

MULTI-METAL

THIS IS A MATERIAL THAT HAS ARISEN THROUGH TAKING THE BEST OF ALUMINIUM (THE RAPID AND EVEN DISTRIBUTION OF HEAT THAT COMES FROM THE INCREASE IN THERMAL CONDUCTIVITY) AND STAINLESS STEEL (ITS IMPACT RESISTANCE AND EASE OF MAINTENANCE).

THIS MATERIAL IS ALSO COMMONLY KNOWN AS A SANDWICH OR MULTI-LAYER MATERIAL, AS IT IS FORMED BY TWO STAINLESS STEEL LAYERS ON THE OUTSIDE AND A SPECIAL ALUMINIUM LAYER ON THE INSIDE.

NORMALLY THE OUTER LAYERS OF STEEL ARE MADE FROM TWO DIFFERENT ALLOYS. THE PART WHICH FORMS THE OUTER SURFACE OF THE RECEPTACLE AND WHICH WILL BE IN DIRECT CONTACT WITH THE HEAT SOURCE IS OF FERRITIC STAINLESS STEEL SO THAT IT CAN CREATE A SUFFICIENT MAGNETIC FIELD FOR THE RECEPTACLE TO WORK ON INDUCTION HOBS.

THE OTHER STAINLESS-STEEL LAYER, WHICH PROTECTS THE ALUMINIUM, AND WHICH WILL BE IN CONTACT WITH FOOD, IS FORMED FROM 18/10 STAINLESS STEEL.

ITEMS MANUFACTURED WITH THIS MATERIAL ARE USUALLY IDEAL FOR ENSURING AN EVEN DISTRIBUTION OF HEAT WHEN COOKING DELICATE PRODUCTS SUCH AS SAUCES, CREAM, CHOCOLATE, ETC., AND THEY ARE ALSO EXTREMELY ENERGY EFFICIENT WHEN COMPARED WITH OTHER MATERIALS.

MATERIAL: SOLID AND IMPACT RESISTANT.

THERMAL CONDUCTIVITY: HIGH, THANKS TO THE INTERNAL ALUMINIUM LAYER.

USE: SUITABLE FOR VITROCERAMIC, INDUCTION, GAS AND ELECTRICITY.

MAINTENANCE AND HYGIENE: MINIMUM NEED FOR MAINTENANCE. VERY HYGIENIC BECAUSE THE INTERIOR AND EXTERIOR ARE IN STAINLESS STEEL.

GENERALLY, ON THE TOP EDGE OF THE RECEPTACLE, THE ALUMINIUM LAYER IS EXPOSED. WHERE THIS IS THE CASE, THE USE OF A DISHWASHER IS NOT RECOMMENDED AS THE DETERGENTS USED MAY ERODE THE ALUMINIUM.

CLAY

DIT DERIVES FROM A METAMORPHIC ROCK KNOWN AS SANDSTONE OR BRIANÇON PLASTER.

CLAY IS THE MATERIAL USED TO MAKE POTTERY, EASY TO MOULD AND PROCESS, IT CAN BE SMOOTHED, WITH THE POSSIBILITY OF ACHIEVING EXCELLENT ANTI-STICK SURFACES. ITS THERMAL PROPERTIES ARE SIMILAR TO THOSE OF OTHER NON-METAL MATERIALS, OFFERING A VERY LOW THERMAL CONDUCTIVITY THAT ALLOWS YOU TO KEEP FOOD INSIDE AT A HIGH TEMPERATURE EVEN AFTER REMOVAL FROM THE HEAT SOURCE.

ALL THESE PROPERTIES MAKE CERAMIC THE PERFECT MATERIAL FOR SLOW COOKING AT HIGH TEMPERATURES.

CERAMIC

Here we will talk about a whole series of ceramic materials, stoneware, porcelain, etc. obtained by the sintering process, which consists of thermally sealing grains of mineral material through a firing process that reaches a maximum temperature of 600°C, transforming the item into a rigid form that allows us to use it as a receptacle for cooking.

Despite this firing process, kitchen ceramics are generally quite fragile. They have a very low thermal conductivity, inferior to glass. This is why they are often used as insulators.

In the world of cooking, ceramic containers are used to keep food warm inside the receptacle: such as cups of coffee or tea.

Ceramic materials are naturally porous and, if not enamelled, tend to absorb liquids. This absorption profoundly modifies its behaviour during cooking, increasing its thermal conductivity and specific heat capacity.

There are traditional cooking techniques in which the unglazed clay vessel is immersed in water for hours before being used, which then not only ensures better thermal conductivity, but also constant and balanced humidification of the food. For some years, ceramic material has also been used for the production of thin non-stick coatings on cookware.

MATERIAL: VERY MALLEABLE WHICH, AFTER A FIRING PROCESS, BECOMES RIGID BUT FRAGILE. LOW RESISTANCE TO IMPACT.

THERMAL CONDUCTIVITY: LOW HEAT CONDUCTIVITY, HOWEVER IT MAINTAINS THAT HEAT VERY WELL, MAKING IT SUITABLE FOR SLOW COOKING.

USE: SUITABLE ONLY FOR GAS, ELECTRICAL AND OVEN COOKING. (CAUTION: DO NOT APPLY DIRECT HEAT OF A HIGH INTENSITY! THIS MAY CAUSE THE ITEM TO BREAK).

MAINTENANCE AND HYGIENE: FOR OPTIMAL CLEANING, THE USE OF HOT WATER AND NEUTRAL SOAP IS RECOMMENDED

Did you know that?

- It is not dishwasher-safe due to its porosity.

- It is not advisable to store ceramic containers in humid environments or where they can absorb odours.

V

GLASS

GLASS IS A MATERIAL KNOWN SINCE ANCIENT TIMES AND, UNTIL A CENTURY AGO, WAS UNUSABLE FOR COOKING BECAUSE OF ITS LACK OF RESISTANCE TO THERMAL GRADIENTS. THE EXPANSION DIFFERENCE BETWEEN HOT AND COLD PARTS OF THE GLASS CAN EASILY CAUSE IT TO FRACTURE.

UTENSILS USING THIS MATERIAL ARE PRODUCED BY QUICKLY COOLING A MOLTEN MASS FORMED OF MAINLY SILICEOUS MATERIALS.

Did you know that?

In 1915, Jesse Littleton discovered that the addition of boron oxide to crystalline silica drastically reduces the effects of thermal expansion and increases resistance to temperature variations. Thus, borosilicate glass was born, better known under the trade name Pyrex.

Borosilicate glass is used in the kitchen for cooking in receptacles that do not come into direct contact with the flame. Nor can they be subjected to sudden warming or cooling, otherwise they would break.

The thermal conductivity is a great deal less than that of steel, but higher than that of ceramic. These characteristics, together with its transparency that allows food being cooked to be checked, make borosilicate glass a particularly suitable material for slow cooking in the oven.

MATERIAL: TRANSPARENT, WHICH ALLOWS THE FOOD TO BE CHECKED AS IT COOKS. THIS MAKES BOROSILICATE GLASS PARTICULARLY SUITABLE FOR SLOW BAKING IN THE OVEN. DELICATE AND LIGHT, IT IS NOT RESISTANT TO THERMAL SHOCK. HOWEVER, BECAUSE IT IS NON-POROUS, IT IS RESISTANT TO CORROSION AND CHEMICALS.

THERMAL CONDUCTIVITY: VERY LOW, ONLY A LITTLE HIGHER THAN CLAY.

USE: IDEAL FOR OVEN COOKING. IT CAN ASLO BE USED IN MICROWAVE OVENS. DIRECT HEAT MUST NOT BE APPLIED TO THE RECEPTACLE.

MAINTENANCE AND HYGIENE: EASY CLEANING, PREFERABLY WITH HOT WATER AND NEUTRAL SOAP. SUITABLE FOR DISHWASHERS.

STRUCTURES AND FORMS IN COOKING

COOKWARE, IN THE MOST GENERAL SENSE OF THE TERM, COMPRISES RECEPTACLES SUITABLE FOR COOKING FOOD. THEREFORE, THEY MUST HAVE TWO FUNDAMENTAL CHARACTERISTICS:

• MATERIALS SUITABLE FOR REMAINING IN CONTACT WITH THE FOOD WITHOUT IT BECOMING CONTAMINATED

• A STRUCTURE AND FORM SUITABLE FOR TRANSMITTING HEAT TO THE FOODSTUFF

Firstly, we must bear in mind that materials that come into contact with food should not react chemically with food.

This is an essential condition which generally excludes most plastics and also many types of metal. But it also should be noted that whether or not a material will contaminate the food depends on the temperature: some plastics are not suitable for cooking, but they are perfect for the microwave or the water bath.

The second condition is much more complex and varied. Materials must withstand cooking temperatures without significant structural changes. This means that they should not melt and must be resistant to thermal shocks.

As for heat transfer, we need to be more specific. There are different ways to transmit heat (as we explained above) and there are suitable cooking vessels for each of these methods.

The fundamental distinction depends on whether or not there is direct contact between the vessel and the heat source. In the first case, we talk about transmission by conduction (in the case of fluids, if they are in motion, we talk about convection), in the second case, transmission by radiation

TRANSMISSION BY CONDUCTION

Heat transfer through empty space is known as radiation. With radiation, heat is transferred in the form of radiant energy, or wave movement, from one body to another body. That is, it does not require matter to heat. Modern technology has introduced two new kitchen tools which work through radiation but which have peculiar characteristics and therefore have to be treated as examples of their properties: the microwave oven and the magnetic induction hob.

CONVECTION CONDUCTION RADIATION

TRANSMISSION BY RADIATION

STRUCTURES AND FORMS IN THE KITCHEN

We will look further at these aspects. At the moment, what we are interested in highlighting is the difference in structure between those cooking vessels designed for direct contact with the heat source and the others. In fact, the part of the container that comes into contact with the heat source inevitably takes on a different function from the other parts and often requires a specific structure, because it is also the part that comes into contact with food. There are two important exceptions, which are cooking by total immersion in liquid (water or oil) and some types of steaming.

BUT APART FROM THESE, WE CAN SAY THAT THE TYPICAL STRUCTURE OF RECEPTACLES FOR COOKING IN DIRECT CONTACT IS COMPRISED OF THREE OR FOUR FUNCTIONALLY AND STRUCTURALLY DIFFERENT PARTS:

LID

HANDLES

WALLS

BASE

BASE

The base is primarily responsible for the heat exchange between the heat source and food. To cook at a stable temperature, it is best if this is able to store large amounts of heat, while the opposite is true if it is necessary to cool food rapidly (e.g. in the cooking of sugar).

As we have seen above, the materials used for the manufacture of cookware have very different reactions to heat. Copper and aluminium offer great thermal conductivity properties, providing a fast and even distribution of heat throughout the receptacle, but with the disadvantage of maintaining that heat for a short time. We have already mentioned that stainless steel has low thermal conductivity. Therefore, the containers made with this material have a base known as a “thermal diffuser”, colloquially known as the “sandwich” base, which is intended to compensate for the low conductivity of steel.

IT IS A SUPPLEMENTARY BASE FORMED BY A THICK ALUMINIUM LAMINATE. WE SHOULD ENSURE THAT THIS BASE IS OF THE CORRECT THICKNESS IN ORDER TO OFFER LASTING RESULTS (BETWEEN 2.5 AND 5 MM FOR DOMESTIC COOKWARE, AND BETWEEN 5 AND 10 MM FOR PROFESSIONAL USE RECEPTACLES). THIS BASE IS ALSO PROTECTED BY A THIN STAINLESS-STEEL SHEET, CREATING, TOGETHER WITH THE MATERIAL OF THE BASE OF THE RECEPTACLE, A “SANDWICH” OF MATERIALS (STAINLESS STEEL + ALUMINIUM + STAINLESS STEEL), HENCE ITS NAME.

This marriage between aluminium and stainless steel is no easy task, as we are joining two materials that react differently to heat. This implies that, on occasions, the thermal diffusing base can come apart. This is why the welding process of the different materials is very important in order to prevent them separating.

The most reliable process for making this bond is what is called friction or impact welding. This technique involves preheating the components that form the thermal diffusing base (stainless steel + aluminium + stainless steel) and subjecting them to high pressure. The aluminium part expands and is welded to the other materials, making them practically impossible to separate.

Returning to the composition of the “sandwich” base, usually the stainless-steel sheet that protects the aluminium layer is of a different alloy than that used in the manufacture of the cookware body (18/10 stainless steel). It is a stainless steel with a higher iron content and with a low percentage of nickel or none at all, which gives it magnetic properties that make it suitable for induction cookers. This alloy is known as ferritic stainless steel, 18/0 or AISI 430.

The protective sheet on the base, known as encapsulation, can cover the entire surface of aluminium including the sides or it can protect only the base of the aluminium disc, in this case we will talk about a “technical” base.

We talk about an encapsulated diffusing base when the ferritic stainless-steel sheet covers the entire aluminium section, including the sides. It is a cap or capsule that protects the entire diffuser bottom.

With an encapsulated base, we cannot see the aluminium inner part, which means that we cannot see if it covers the entire cavity.

Where the aluminium inner part does not cover the entire inside of the capsule or simply does not exist inside, it creates an effect contrary to the idea of the sandwich base, as with the absence of all or part of the aluminium, an air space is created inside which acts as an insulator and which makes it even more difficult to transmit heat throughout the vessel.

This malpractice is not usual, but in some cases it is done in order to lower manufacturing costs which, as we mentioned above, can lead to problems of efficiency.

ENCAPSULATED BASE

It is characterized by the fact that the material does not cover the whole of the thermal-diffusing base. The aluminium section is protected by a ferritic stainless-steel sheet at its base, but it does not cover the sides of the aluminium. This feature allows the thicknesses of the different materials that make up the sandwich bottom to be observed by the naked eye.

TECHNICAL BASE

INCORRECTLY ENCAPSULATED BASE

THE ALUMINIUM SECTION DOES NOT FILL THE ENTIRE CAVITY OF THE ITEM

A poor fixation of the capsule to the body of the pot creates gaps in the item that allow water and detergents to get inside, causing an erosion of the aluminium layer and a very noticeable loss of efficiency.

As illustrated in the example image, an incorrectly encapsulated base is also one where the aluminium layer is virtually non-existent.

CORRECTLY ENCAPSULATED BASE

THE ALUMINIUM SECTION DOES FILL THE ENTIRE CAVITY OF THE ITEM

It is very important that the aluminium protective layer is properly attached to the bottom of the container. That is, there should be no holes in the welding as these would allow water and detergent to get inside the aluminium layer, causing erosion without us realizing it, making it disappear and consequently making the receptacle very inefficient when it is being heated.

Another very obvious aspect for improving the energy efficiency of cookware, but no less important and easier to control, is to make sure that the diameter of the thermal diffusing base is similar to the diameter of the heat source we are using. If there is a big difference between them (either larger or smaller) it will significantly reduce efficiency and consequently we will waste more energy and time.

WALLS

THE WALLS OR SIDES OF THE COOKWARE ARE RESPONSIBLE FOR KEEPING BOTH FOOD AND HEAT INSIDE. THEREFORE, AS WITH THE BASE, WE HAVE TO TAKE INTO ACCOUNT THE IDEAL THICKNESS FOR EACH ITEM.

HEAT FLOWS ALMOST EXCLUSIVELY FROM THE LOWER PART (BASE), SO IT IS PREFERABLE THAT THE BODY OF THE RECEPTACLE DOES NOT HAVE A HIGH THERMAL CONDUCTIVITY IN ORDER TO PREVENT UNNECESSARY HEAT DISPERSION. WHAT WE WANT IS TO MINIMIZE THE TEMPERATURE DIFFERENCE BETWEEN THE LOWER PART AND THE TOP OF THE COOKING RECIPIENT.

STRUCTURES AND FORMS IN THE

HANDLES

Handles affixed to the sides of cookware are used to manipulate cooking receptacles safely.

It is clear that the material from which the handles are manufactured is very important, since their function is to prevent burns. For this reason, they are commonly manufactured using materials that have low thermal conductivity in order to prevent rapid overheating. Here we discuss those made out of plastic, wood or stainless-steel materials. The first two materials are mainly used for the manufacture of handles for household utensils. The third material, stainless steel, is most used in the production of cookware for professional use.

RECEPTACLES FITTED WITH TWO SIDE HANDLES ARE GENERALLY THOSE THAT CAN HOLD A LARGE AMOUNT OF LIQUID OR FOOD, AND WHICH REQUIRE TWO HANDS TO MANIPULATE OR TO MOVE. THESE RECIPIENTS ARE IDEAL FOR STATIC COOKING WHICH IS REQUIRED TO STAY IN CONTACT WITH THE HEAT SOURCE FOR A CONSIDERABLE TIME. AMONG THESE WE WOULD MAINLY INCLUDE STOCKPOTS AND COOKING POTS.

STRUCTURES AND FORMS IN THE KITCHEN

In contrast, single handles are joined to those containers that have a lower capacity, usually in shorter receptacles and which are very close to the flame. Here we mean frying pans and saucepans.

These are used in those gastronomic preparations where the food needs to be moved around continuously, such as when sautéing. The handle provides good support for the pan while performing this task.

We have previously mentioned that handles are usually manufactured from materials with a low thermal conductivity, such as stainless steel, however there is an exception. In the professional market we can find ranges of pans where the handles are made from flat iron sheet, a material that can reach high temperatures.

ERGOS HANDLES

WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF USING RECEPTACLES WITH STAINLESS STEEL OR IRON HANDLES?

Generally stainless-steel handles, Ergos handles for example, are manufactured from a hollow tube creating an internal air chamber that acts as a heat insulator.

It is very important that the ends of the handle are well sealed to prevent water getting in, as when heated, it will cause steam to escape which can cause injury to the cook. In many cases, we find open handles with two holes at the lower end, so that the water can easily come out once it has been washed, preventing it from accumulating inside.

WATER DRAINAGE HOLES THAT ALSO FACILITATE AIR CIRCULATION THROUGH THE INTERIOR OF THE HANDLE

MORE ERGONOMIC ERGOS HANDLES

The ergonomics of the stainless-steel handle are also important, as we start from a cylindrically tube, which must be flattened slightly to achieve greater grip.

Handles on which this “flattening” process is not performed can slip and rotate with the weight of the receptacle.

INTERIOR CHANNEL

POLISHED EDGES

HERCULES HANDLES STRONGER ATTACHMENT

As for handles made from flat iron sheet, the Hercules handles for example, they must be coated with a protective paint, resistant to high temperatures, in order to avoid rapid oxidation. This handle has polished edges and a slight channel in the middle for better support

These types of handles have the disadvantage in that they retain a lot of heat and can reach high temperatures. That is why, when using this type of handle, it is essential to protect your hands with an oven-glove or cloth to avoid injury.

Another aspect is the length of the handles which is very much related to what you want to use the receptacle for. However, as a rule, we would say that the ideal length should be equal to or greater than the diameter of the receptacle.

STRUCTURES AND FORMS IN THE KITCHEN

ATTACHING THE HANDLES TO THE COOKWARE ITEM IS A PROCESS THAT MUST BE CARRIED OUT WITH GREAT CARE IN ORDER THAT THEY DO NOT COME AWAY FROM THE BODY OF THE RECEPTACLE.

THIS PROCESS CAN BE DONE WITH RIVETS OR BY WELDING.

DIRECTLY WELDED JOINTS

Directly to the body of the receptacle.

When we talk about fixing handles by welding, it is very important to identify the number of welding points that have been applied, as these are directly proportional to the strength of the handle. The more welding points, the more securely it is affixed to the body of the vessel and, thus, the safer it is.

In any case, there are two separate techniques. In one, the handle is welded directly to the body of the receptacle.

INDIRECTLY WELDED JOINTS

(plate + bar + container)

Here, the handle consists of two parts. A stainless-steel base (plate) and a rod (handle) which are joined together. The resulting assembly is then attached to the body of the item. This type of handle is more secure, as many more welding points can be applied and this allows the entire force that passes through the handle to be spread across the entire surface of the plate.

RIVETED JOINTS

If the rivets are of the same material as the receptacle, they will behave in the same way when they are heated or cooled. Where this is not the case (rivets and body of different materials) we may encounter different expansion and contraction behaviours which can cause them to become loose and move.

INDIRECTLY WELDED JOINTS

(plate + bar + container)

PLATE

The join between plate and rod has to be very secure because, if this process is not done with care, the rod can separate and cause significant injury. It is for this reason that it has to be welded completely, as illustrated in the next image.

Where the welding points are applied in order to join the assembly to the receptacle.

The bar allows the receptacle to be supported and manipulated by hand.

If attaching the handles is already a delicate task, it is even more so when we are joining three parts (plate + bar + receptacle). Here we must not only take into account the bonding between the plate and the bar, but also when this assembly is attached to the body of the receptacle.

STRUCTURES AND FORMS IN THE KITCHEN

LIDS ARE THOSE COOKWARE ITEMS THAT ALWAYS END UP BECOMING A NUISANCE THROUGH NOT KNOWING WHERE TO STORE THEM, AND WHEN THEY ARE NEEDED, ONE CAN NEVER TO FIND THE RIGHT DIAMETER. A VERY COMMON OCCURRENCE IS USING THE FIRST LID WE FIND, EVEN IF IT IS A LARGER SIZE THAN THE RECEPTACLE BEING USED But without a doubt, lids have a very important role: keeping both the food and the heat inside the receptacle. That is why it is preferable that they are made of a material that does not conduct heat, such as glass or stainless steel.

LIDS

To achieve maximum efficiency of a lid, it is important that it fits the diameter of the cookware. Otherwise we will waste energy unnecessarily.

The ergonomics of the lid are also important in improving its efficiency. We can find lids that rest on the top of the container, others that fit on the inside and others that, in addition to resting on the top, have a small lips that also cover the outer edge and which allows for a more effective seal without being airtight.

We can also find lids with silicone gaskets to make sure they are airtight. In these cases, it is essential that the lid has a valve that regulates the outlet of steam.

All lids are equipped with knobs or handles that facilitate their use. Like the handles of cookware, they must be made of materials with low thermal conductivity in order to avoid injury when handling. We usually find them in synthetic resins, plastics resistant to high-temperatures (such as Bakelite) or even stainless steel.

Often, and especially on household utensils, the knobs and handles of lids made of metallic materials are coated with silicone to increase their heat insulation.

COOKWARE:

AS WE’VE SEEN, THERE ARE DIFFERENT MATERIALS USED FOR THE MANUFACTURE OF COOKWARE, EACH OF THEM WITH DIFFERENT BEHAVIOURS AND PROPERTIES.

IN THIS REGARD, IT IS ESSENTIAL TO SPECIFY WHAT TYPE OF FOOD WE WANT TO COOK AND WHAT TYPE OF COOKING WE WISH TO PERFORM. THUS, WE CAN CHOOSE NOT ONLY THE COOKING VESSEL THAT WE WILL USE, BUT ALSO WHAT MATERIAL IT SHOULD BE MADE OUT OF IN ORDER TO ACHIEVE THE BEST RESULT.

IN FACT, THE GREAT VARIETY OF COOKING VESSELS THAT A CHEF WILL FIND AVAILABLE IN THE MARKET HAS ARISEN THROUGH THE DEFINITION OF THESE SPECIFIC FEATURES.

AS AN INITIAL APPROACH TO THE SUBJECT, IT IS USEFUL TO START ANALYSING IN DETAIL THE MAIN TYPES OF COOKING VESSEL USED IN THE KITCHEN IN ORDER TO TRANSFORM FOOD THROUGH HEAT.

FOR THIS REASON, WE’LL MAKE AN INITIAL CLASSIFICATION: THOSE RECIPIENTS THAT HAVE TWO SIDE HANDLES AND THOSE THAT HAVE ONE HANDLE.

COOKWARE: FORM AND FUNCTION

IN THE FIRST GROUP WE FIND THE STOCKPOTS, COOKING POTS AND PAELLA PANS. IN THE SECOND GROUP, MAINLY SAUCEPANS, FRYING PANS, SAUTÉ PANS. IN THE TWO CLASSIFICATIONS, WE WILL FIND RECEPTACLES OF DIFFERENT SHAPES WHERE THE HEAT TRANSFER MECHANISMS MAY VARY DRASTICALLY. FOR THIS REASON, HAVING A RANGE OF COOKWARE OF VARYING SIZES AND SHAPES IS RECOMMENDED. IN THIS WAY WE CAN GET THE MOST OUT OF EACH ITEM WHICH WILL ALLOW US TO ACHIEVE THE BEST RESULTS.

STOCKPOTS

These are the tallest vessels that form part of the cookware range. We could consider them as being those receptacles whose sides are at least as high as the diameter of the uppermost part

Regarding stockpots, it is worth noting the low ratio between their volume and the evaporation surface (the surface of the liquid in contact with the air). Their proportions between the diameter of the base and the height of the vessel make them ideal for containing a lot of liquid with lower evaporation in relation to saucepans. For this reason, stockpots are limited to immersion cooking and are ideal for making broths, stews, soups and cooking legumes in quantity. Aqueous liquids (these would exclude oils, for example) evaporate much more slowly. Inside these vessels, liquids circulate very efficiently due to convection movements. The flow in contact with the base of the receptacle is heated, expanded and, due to the decrease in density, begins to rise. Meanwhile, the liquids on the upper part move downwards. This rotational movement allows heat to be efficiently transported throughout the contents of the receptacle, but sometimes, such as when boiling over a high heat, this movement can become too violent and spoil solid food. Therefore, when cooking particularly delicate fish, the use of a low and wide receptacle minimizes this convection effect. To optimize the boiling process and minimize evaporation, it is highly recommended to use a lid which gives the item greater caloric efficiency.

As opposed to stockpots, we identify as cooking pans all those vessels where height of the side walls is less than their diameter. This is why they have a volume / evaporation surface ratio higher than that of the stockpots, making them more efficient receptacles when it comes to heating the contents.

With cooking pans, we can differentiate two types according to their height: tall pans and low pans. The first are identified through the height of the walls usually being about 2/3 of their diameter, and are ideal for pastas, boiled rice, and vegetables.

Low cooking pans have sides of a height approximately one third of the diameter. Thanks to their low height and wide opening, they can be used for rapidly evaporating liquids. They are also very useful for sweating onions and vegetables (mirepoix) or for slow cooking and to concentrate and reduce liquids. In both cases, they allow a greater evaporation of fluids than the stockpots, but more so for low cooking pans.

COOKING PANS PAELLA PANS

These are the cooking receptacles with a very low ratio between the diameter of the base and the low height of the sides. Their extra low design gives them a large evaporation surface.

They are therefore ideal for cooking rice among other items. Sometimes they include a lid and are always equipped with handles on each side. We must choose the diameter of the paella dish depending on the number of diners for whom we are going to cook.

COOKWARE: FORM AND FUNCTION

COOKWARE: FORM AND FUNCTION

WE HAVE BEEN SPEAKING ABOUT COOKWARE WITH SIDE HANDLES. AS FOR COOKWARE WITH A SINGLE HANDLE, WE FIND THE FOLLOWING KITCHEN TOOLS: FRYING PANS, SAUTÉ PANS, SAUCEPANS AND WOKS.

Frying pans are those receptacles that have a round shape with higher or lower walls (depending on the cooking function for which they will be used) and are slightly convex.

The materials used for their manufacture can vary between iron, copper, stainless steel, aluminium and multi-metal.

Frying pans are often used intensively, starting with sudden, repetitive movements made by the chef with his arms. This is where weight plays an important role, because the lower the weight, the easier they are to use and injury to wrists, elbows and shoulders, very frequent in the professional world, is greatly reduced. Therefore, chefs prefer to use frying pans made of lightweight materials.

Many frying pans are presented on the market with an inner layer, usually black, which prevents the adhesion of food to the receptacle. This non-stick inner coating may be composed of plastic polymers derived from polytetrafluoroethylene (PTFE), but they may also be made of stone or ceramic. The type of material chosen, of course, involves different behaviours during cooking.

It is important that the non-stick layer applied to an item for cooking is sufficiently resistant in order to prevent it from being easily detached from the container. It must be abrasion resistant. For this reason, when using non-stick cookware, it is always recommended to use utensils made of soft materials (plastics, wood, silicone) and to avoid the use of metallic and/or sharp utensils so that the non-stick properties of the vessel last longer.

FRYING PANS SAUTÉ PANS

Their name derives from the French “sauter” (to jump) and we could consider them a hybrid between a saucepan and a frying pan. They are characterized by having straight walls and a height of between 6 and 7 cm. Thanks to their design, in which the surface in contact with the heat source is large compared to the height of its walls, they allow food to be distributed around the base of the container in a single layer and consequently heated evenly.

The straight structure of their walls prevents food from being tossed out of the pan when sautéing, while allowing liquids, wines or sauces to be introduced, making them ideal for stews and for deglazing.

SAUCEPANS

Saucepans, like sauté pans, are receptacles with a single handle. They usually have a small diameter and come in different shapes and heights. If we classify them by their shape, we can find:

STRAIGHT-SIDED SAUCEPANS

They have straight walls, as indicated by their definition. Their height may vary, thus we talk of short or tall saucepans, but in all cases, they are lower than their diameter.

They are ideal for making sauces, creams, emulsions and auxiliary cooking.

ROUNDED SAUCEPANS

Their main feature is the rounded walls which do not form a right angle with the base. This makes mixing food easy, leaving no corners where the spatula cannot reach.

They are ideal for making more solid creams or chocolate, where the food requires constant stirring.

CONICAL SAUCEPANS BAIN MARIE

This type of saucepan is characterized by convex walls, where the diameter of the bottom is less than the diameter of the upper parts (conical shape) which allows a rapid evaporation of liquids.

We can also include the Bain Marie in this category, containers very similar to a stockpot (usually the height of the walls is the same as the diameter of the container), but of much smaller dimensions, ideal for boiling small quantities of food (mainly liquids that require minimal evaporation).

WOKS

Woks are oriental-style frying pans. They are used for rapid cooking and for moving food quickly around the pan. Usually they have a concave shape, with a smaller diameter on the bottom than they do at the top.

This design, where there is a large surface area in contact with the heat source compared to the height of the walls, allows food to be distributed throughout the base of the container in a single layer and, consequently, to be heated evenly.

COOKWARE: FORM AND FUNCTION

COOKING, HEAT AND TEMPERATURE

HEAT IS THE FORM OF THERMAL ENERGY THAT PENETRATES THE MATERIAL. THE HIGHER THE TEMPERATURE OF AN OVEN FOR EXAMPLE, OR A POT FILLED WITH WATER, A FRYING PAN ETC., THE MORE THERMAL ENERGY WILL BE TRANSMITTED TO THE FOOD AND THEREFORE THE GREATER THE CHANGE IT WILL CAUSE.

TEMPERATURES BETWEEN

This causes enough change to kill the majority of microbes and to cook eggs, delicate meats and fish without drying them out too much or making them hard.

TEMPERATURES AROUND THE BOILING POINT OF WATER

This provides enough energy to kill most microbes, blanch vegetables, cook potatoes, legumes and cereals. But they dry out and harden eggs, fish and some meats.

TEMPERATURES OF

NORMALLY CHEFS WORK WITH THREE TEMPERATURE RANGES: 55º - 70ºC 100ºC 150ºC AND ABOVE

This makes the surfaces of food crunchy and cause the development of brown colours and rich flavours.

Accurate measurement and temperature control are very important for the culinary process, sometimes 1 or 2 degrees can mean a noticeable difference in the final product. For this reason, more and more temperatures are specified accurately, sometimes to decimal places. Heat is transferred to food by contact or radiation.

Direct contact can be with a hot surface or with water, oil, steam or hot air. The air heats the food slowly because it is much less dense than the other elements. This is why we can leave our hand in a hot oven for a few seconds but not in boiling water or oil.

Radiated heat transfers energy to food remotely through so-called infrared radiation. All objects, even those that are cold, radiate at least some heat energy. It’s the heat we feel, for example, when we move our hand towards a hot frying pan or when we’re in the sun. The metal walls of ovens transfer heat by radiation, while warm air inside does so by contact. Hot coals can have a temperature of around 1650°C, as do gas flames. An electric stove on the other hand can reach 1100°C and for this reason it is very important to have cookware that ensures efficient thermal distribution. It is recommended not to use a burner or flame larger than the pot or pan because up to a third of the energy is lost and the items can be damaged.

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