⚡ Quick Answer
'Surgical grade' steel (Grade 316) and 'food grade' steel (Grade 304 / 18/8) are both safe for food contact, but Grade 304 is the correct and standard grade for water bottles. Grade 316 has higher molybdenum content for industrial/saline environments — no meaningful improvement for water. BIS IS 17526:2021 mandates food-grade (Grade 304) steel; all HYV bottles use it.
Steel Grade Facts
What 18/8 Actually Means
18/8 is shorthand for the alloy composition of Grade 304 stainless steel: 18% chromium and 8% nickel. The chromium creates the passive oxide layer that makes the steel corrosion-resistant and non-reactive. The nickel stabilises the austenitic structure. This composition has been used in food processing, catering, and commercial kitchens for decades because of its non-reactivity with food and liquids.
Grade 316 — What It Actually Is
Grade 316 (often called 'surgical grade' or 'marine grade') adds approximately 2% molybdenum to the Grade 304 composition. This molybdenum significantly improves resistance to chloride corrosion — which is relevant for marine environments, surgical instruments in saline solutions, and industrial chemical processing. For a water bottle containing fresh water, coffee, or tea, there is no meaningful difference in performance or safety between Grade 304 and Grade 316.
The 'Surgical Grade' Marketing Problem
Some water bottle brands market their products as 'surgical grade stainless steel' to imply superior safety. This is misleading for two reasons. First, Grade 316 is not meaningfully safer than Grade 304 for fresh water contact. Second, if a brand claims Grade 316 without independent certification, there's no way to verify the steel grade. BIS IS 17526:2021 certification tests the actual steel interior — regardless of what grade the brand claims.
LuxeFlow — Grade 304, no interior coating
CoreFlow — BIS certified Grade 304
💡 The Only Verification That Matters
The only independent verification that a water bottle's interior is food-grade stainless steel is BIS IS 17526:2021 certification. This standard includes heavy metal migration testing from the steel interior. A brand claiming 'surgical grade' or '316 steel' without BIS IS 17526:2021 certification provides no independently verified safety assurance.
Frequently Asked Questions
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