SUS304 vs 316 vs 18/8 Stainless Steel: Which for a Water Bottle?
The alloys decoded — and the one grade you should refuse.
The short answer: 304 stainless (also written 18/8) is the food-grade standard for water bottles and is the right choice for water, coffee and tea. 316 adds molybdenum for extra corrosion resistance and is worth it for salty or acidic drinks or a premium line. Avoid 201 stainless — it cuts cost by cutting corrosion resistance.
We salt-spray test both, so this isn't a guess: across roughly 300 batches, 316 resisted rust about 32% better than food-grade 304. For everyday water bottles 304 is plenty; if you're building a premium line — or shipping to coastal, high-salt markets — 316 earns its upcharge.
What the numbers mean
The grade describes the alloy mix. The two numbers in "18/8" are the percentages of the two key metals:
304 / 18/8: about 18% chromium and 8% nickel. Chromium resists corrosion; nickel adds strength and a clean finish. This is the food-grade workhorse.
18/10: same family, about 10% nickel — a touch more corrosion resistance and a premium feel, common in flatware.
316: 304 plus roughly 2% molybdenum, which sharply improves resistance to salt and acid (it is sometimes called "marine grade").
201: replaces much of the nickel with manganese to cut cost — and corrodes more easily. Not a grade you want touching drinks.
Forming food-grade stainless bottle bodies in our metalworking workshop
Which should you specify?
Use case
Recommended grade
Why
Water, coffee, tea (most bottles)
304 (18/8)
Food-grade, durable, cost-effective
Salty electrolyte / acidic drinks
316
Molybdenum resists salt & acid pitting
Premium flatware-style finish
18/10
Slightly higher nickel, premium look
Lowest price at any cost
— avoid 201 —
Poor corrosion resistance for food use
How to verify what you're actually getting
The catch is that 304 and 201 look identical. Some suppliers quote 304 and ship 201 to hit a target price. Protect yourself by asking for the mill grade certificate with your order, and request a sample. We build to 304 food-grade as standard, offer 316 on request, and never substitute 201.
Bottom line: 304 for everyday drinks, 316 when salt or acid is involved, and always get the grade in writing. The difference is real corrosion resistance, not marketing.
What is the difference between SUS304 and 316 stainless steel?▾
304 (18/8) is the food-grade standard — about 18% chromium and 8% nickel. 316 adds around 2% molybdenum, giving much better resistance to salt and acid. Use 304 for water and coffee; choose 316 for salty/acidic drinks or premium lines.
Does 18/8 mean the same as 304 stainless steel?▾
Yes. 18/8 refers to about 18% chromium and 8% nickel, which is the composition of 304 stainless steel. 18/10 is the same family with slightly more nickel.
Is 201 stainless steel safe for water bottles?▾
201 replaces nickel with manganese to lower cost and has weaker corrosion resistance, so it is not a good choice for food contact. Insist on 304 food-grade and ask for the mill certificate.
How can I confirm a bottle is really 304?▾
304 and 201 look the same, so request the mill grade certificate with your order and a physical sample. A reputable factory builds to 304 as standard and will provide documentation.
Sourcing drinkware? Talk to Beyond at Jupeng — a real factory since 1998, factory-direct pricing, FDA/LFGB/EU/Prop 65 certs ready, MOQ from 500 pcs, 30-day production. We usually reply within 24 hours.
Written by the Jupeng Drinkware team — Yongkang, Zhejiang, China. Manufacturing drinkware since 1998. Contact Beyond: [email protected] | WhatsApp +86 156 5791 8881