Stainless steel 304 and 316L
| ABNSABNS — Acid-Based No-Rinse Sanitiser The class of acid-based sanitisers used in homebrewing, combining phosphoric acid with an anionic alkylbenzenesulfonate surfactant. The acid creates a low-pH environment hostile to microorganisms; the surfactant disrupts cell membranes. Examples: Star San, Sanipro Rinse, StellarSan, Chemsan. Approved for use on food-contact surfaces without rinsing when used at the manufacturer's specified dilution. | DESDES — Disinfectant Ethanol Sanitiser ChemiPro DES. An ethanol-based (70–80%) sanitiser with no non-volatile residue. Evaporates completely, leaving no WDC risk. A-rated for all common homebrewing materials. | Cleaning | Beer/wortWort Liquid extracted from malted grain during mashing and boiling, before fermentation. The starting point for beer. | |
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| Rating | A | A | A | A |
Stainless steel is the reference construction material for commercial brewing equipment and appears in homebrewing as Cornelius kegs, mini kegs, NukaTap bodies, and pressure-rated vessels. Both 304 and 316L (the molybdenum-containing marine grade) are used; the difference matters primarily for chloride-containing environments. For homebrewing with standard ABNSABNS — Acid-Based No-Rinse Sanitiser The class of acid-based sanitisers used in homebrewing, combining phosphoric acid with an anionic alkylbenzenesulfonate surfactant. The acid creates a low-pH environment hostile to microorganisms; the surfactant disrupts cell membranes. Examples: Star San, Sanipro Rinse, StellarSan, Chemsan. Approved for use on food-contact surfaces without rinsing when used at the manufacturer's specified dilution., DESDES — Disinfectant Ethanol Sanitiser ChemiPro DES. An ethanol-based (70–80%) sanitiser with no non-volatile residue. Evaporates completely, leaving no WDC risk. A-rated for all common homebrewing materials., and PBWPBW — Powdered Brewery Wash A sodium metasilicate and percarbonate-based alkaline cleaner widely used in brewing. Removes organic soil through alkaline hydrolysis. A-rated for all common homebrewing plastic and elastomer materials at working concentrations. chemistry, 304 is entirely adequate.
How stainless steel resists corrosion
The corrosion resistance of stainless steel depends on a passive oxide layer — primarily chromium oxide (Cr₂O₃) — that forms spontaneously on the surface on air contact. This layer is thermodynamically stable at the pH ranges of all homebrewing chemicals and is self-healing if mechanically damaged: expose fresh metal to air, and the oxide layer reforms.
The principal threat to the passive layer is chloride ions. Chloride can penetrate the oxide layer at defect sites and initiate pitting corrosion — a localised, self-propagating form of attack that is difficult to reverse once established. 316L has better resistance to chloride-initiated pitting than 304, due to the molybdenum addition.
For homebrewing practice: ABNSABNS — Acid-Based No-Rinse Sanitiser The class of acid-based sanitisers used in homebrewing, combining phosphoric acid with an anionic alkylbenzenesulfonate surfactant. The acid creates a low-pH environment hostile to microorganisms; the surfactant disrupts cell membranes. Examples: Star San, Sanipro Rinse, StellarSan, Chemsan. Approved for use on food-contact surfaces without rinsing when used at the manufacturer's specified dilution. sanitisers (Star SanSAN — Styrene-Acrylonitrile copolymer A transparent plastic used in some airlocks and equipment. The acrylonitrile content gives better chemical resistance than GPPS, particularly against DDBSA in acid-based sanitisers. Rated A for ABNS, unlike GPPS which is rated B/D., Sanipro Rinse, StellarSan, Chemsan) contain no chloride — they are phosphoric acid and DDBSADDBSA — Dodecylbenzenesulfonic acid The active surfactant in acid-based no-rinse sanitisers (ABNS). A long-chain anionic surfactant that disrupts microbial cell membranes at low pH. Non-volatile — it concentrates on surfaces as water evaporates. based. PBWPBW — Powdered Brewery Wash A sodium metasilicate and percarbonate-based alkaline cleaner widely used in brewing. Removes organic soil through alkaline hydrolysis. A-rated for all common homebrewing plastic and elastomer materials at working concentrations. contains no chloride. Chloride risk in homebrewing comes from: bleach or chlorinated sanitisers used without thorough rinsing, and in some circumstances from high-chloride municipal tap water used for mixing cleaning solutions. Standard practice with the chemicals discussed in this guide presents no pitting corrosion risk to 304 stainless.
Passivation
Passivation — immersion in dilute citric or nitric acid to regenerate the oxide layer — is recommended for new stainless equipment and after any significant mechanical surface damage (grinding, welding, deep scratching). It is not required as a routine step in normal homebrewing cleaning cycles, where the oxide layer is maintained by normal air exposure between uses.
Compatibility — ABNS / DES / Cleaning / beer/wort: A
Stainless is one of the least chemically constrained materials in the register. No concern in any homebrewing chemical environment using the chemicals described in this guide.