Zinc is a common alloy material used in cookware. It is relatively inexpensive and has good thermal conductivity, but it is also reactive to acidic foods, causing them to discolour or develop a metallic taste, so brass cookware must be lined with another metal (usually tin) to prevent this. This process is called kalai or tinning, and how frequently brass cookware needs to be tinned depends on how often it is used. Brass is also not as durable as copper and can tarnish or corrode with time, making it less suitable for long-term use.
Copper is a superior heat conductor than brass, and it distributes heat evenly so that food can be cooked more quickly and to a consistent temperature. It has natural anti-microbial properties, and it can preserve the nutrients in foods like vegetables. However, it is prone to scratching and can tarnish and corrode easily if not properly cared for. Copper cookware requires regular cleaning and tinning, and it may need to be replaced more frequently than other types of cookware.
Aluminium is soft and cheap, and it conducts heat well but doesn’t retain it very well. It is reactive to acid, and that’s why it is never sold in its bare form; it’s always coated. The coating itself is usually made from tin, which is safe to use, but it can contain trace amounts of lead and cadmium.
Some manufacturers produce cast aluminium cookware by combining it with steel, which increases its strength and makes it more resistant to corrosion, but this reduces the heat conductivity. It is important to choose cookware made from materials that are safe to use and easy to clean, such as stainless steel or nonstick coatings.