# Surface finish and maintenance ### Introduction All our steel products are made from high-quality grade 304 stainless steel. Proper maintenance is essential; however, the required care will depend on the type of surface treatment applied during production. Our products come in three surface finishes: polished, electropolished, or our proprietary PureBlast™ finish. Products with electropolished or PureBlast™ surfaces do not require passivation, unlike polished surfaces, which do. Stainless steel naturally gains its corrosion resistance when the chromium content in the steel reacts with oxygen, forming a protective oxide layer on the surface. This oxidation process occurs gradually when exposed to air. However, the process can be accelerated within 15–30 minutes through passivation. You can learn more about passivating stainless steel in the section below. ### Electropolishing An increasing number of our smaller products now undergo electropolishing as part of the final manufacturing process. Electropolishing is an electrochemical process in which the product is submerged in an acid bath. Electrical wires are attached to the steel component, turning it into an anode. As electrical current flows from the product (anode) through the electrolyte (acid bath) to the cathode, a controlled material removal takes place. The process, which typically lasts between 2 and 20 minutes, effectively eliminates contaminants and opens micro-pores that are invisible to the naked eye. During electropolishing, a very thin layer of the steel surface (20–40 μm) is removed. As a result, the product becomes easier to clean, the risk of hidden contaminants is significantly reduced, and no additional passivation is required. {% hint style="info" %} Did you know that electropolished steel is considered to have 30 times better corrosion resistance compared to passivated steel? {% endhint %} ### How to passivate? Use Citric Acid or StarSan (phosphoric acid). We recommend passivating the steel before first-time use and 1-2 times a year. Use StarSan or similar acid-based chemicals. Fill the tank with lukewarm water. Use approximately 5ml StarSan per liter and leave it for 15-20 minutes. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.brewtools.com/learn-more/surface-finish-and-maintenance.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.