Why Does Steel Used in Beer Equipment Need To Be Polished?

Polishing stainless steel is a process that creates a mirror-like finish through friction and polishing. Polished stainless steel is easier to clean and disinfect. Because the polished surface lacks pits or grooves, it can be cleaned with high-pressure cleaning sprays or other disinfectants, such as bleach. Polishing stainless steel helps prevent bacteria and other microorganisms from adhering to surfaces like barrels, tanks, and pipes, thereby preventing their growth.

Polished Stainless Steel

Polished stainless steel is more corrosion-resistant, helping you get the most out of your equipment. For example, polished stainless steel is more hygienic because it's easier to clean and doesn't accumulate dirt and bacteria like unpolished stainless steel.

Another advantage of polished stainless steel is its appearance. The mirror finish gives any piece a more modern and attractive look than unpolished pieces.

Welding and Heat Treatment

Welding and heat treatment are two important factors to consider when selecting steel for brewing equipment. Welding is a joining process in which two pieces of metal are heated until molten and then cooled together. The resulting weld typically creates a seamless joint that is stronger than the original metal.

Heat treatment involves heating the steel to high temperatures (approximately 1500°F) to increase its strength and durability, improve its corrosion resistance, and eliminate internal stresses caused by cooling from the high temperature after welding.

Food Hygiene Requirements

Food hygiene is crucial and is regulated by both laws and health authorities. In fact, there are multiple levels of food hygiene standards that must be met. This not only impacts customer safety but also their perception of your brand.

The Beer Equipment Institute points out that polished stainless steel, due to its smooth surface, does not inhibit the growth of bacteria or mold; however, if water containing harmful bacteria comes into contact with this metal (and subsequently food), it can cause serious problems.

The Impact of Mechanical Polishing on Brewing Equipment

To polish a surface, you need to understand its true color. When the oxide layer on steel is removed, the pure metal beneath is exposed. This helps determine if your equipment is rusted or if any contaminants are present during the beer production process. Polishing also removes any dirt or oil that may have accumulated on the equipment during use, potentially affecting the taste of your subsequent drinks!

Beer Equipment Production and Polishing Process

• Stainless steel plates are seam-welded to form the cylinder and conical bottom.

• Pit plates are welded to the cylinder and conical bottom.

• The interior of the cylinder is polished. First, workers polish to remove any visible weld slag. Further polishing is performed using specialized machines with different abrasive belts: 80-grit abrasive belt (RA = 0.2mm) → 120-grit abrasive belt (RA = 0.12mm) → 240-grit abrasive belt (RA = 0.6µm) → 400-grit abrasive belt (RA = 0.2µm). When the 240-grit belt is used, the RA inside the tank is 0.4-0.6µm, ensuring the tank is sanitary and suitable for brewing beer. For some demanding breweries requiring an RA below 0.4µm, we use a 400-grit abrasive belt to improve polishing accuracy. The interior of the conical bottom is polished in the same manner as the cylinder. The top of the disc is polished in the same manner as the cylinder and conical bottom.

• The top, cylinder, and bottom are assembled and welded together.

Beer Brewing Equipment

Interior: No pickling or passivation treatment is required, and the interior is polished to a precision of 0.2-0.4μm with no dead corners.

Exterior: The surface is protected with oil-coated brushed steel, and the welds are polished.