304 Stainless

[JohninWV]

We are looking to get a couple of bulk tanks for alcohol storage. Is 304 stainless the right stainless or do I need 316?

I'm not sure I know the difference. I seem to remember there being a post about this but I can't find it in my searching.

[MusicJunkie]

Finally, after lurking here for months and months, I finally might be able to contribute!

304 will be cheaper, but 316 might be better, as it is more corrosion resistant, and 2205 (think thats the #, dont quote me) would be best, and definitely most expensive.. I didnt emphasize the "might" in that last sentence-- it comes down to cost and life expectancy of the equipment.

The real key is to properly passivate the stainless, creating a protective oxidation coating on the material. Without the oxide layer, the stainless will be vulnerable to attack and eventual degradation and pitting, and ultimately, failure. That would take years, maybe decades, but the pitting would be an issue for possible contamination during storage.

Another possibility would be to go with the cheaper 304, and have it nickle plated, which would eliminate any corrosion or pitting problems.... but the cost of that would probably be prohibitive. So in short-- 304 or 316 will both work, but both would need to be properly passivated and properly maintained. Check out a product called CitriSurf-- its a citric acid passivation solution.

And while not a distiller (yet).... I do know metals, having been a machinist and metallurgist in a previous occupation, and I worked with SS quite a bit. Used the CitriSurf gels to passivate laser etched stainless, and it worked great. So, hope this helps!

[Denver Distiller]

304 is all you need.

[pressure9pa]

304 is generally considered sufficient for food/beverage needs.

[Mike Fiore]

We have a 12,000 case winery and a small distillery, all my ss tanks are 304. Some of the tanks are almost 30 years old but still in great shape. A couple of years ago while talking to a Canadian tank company they sounded like they were running a campaign against 304 ss. Because I need some temp tanks for storage of brandy,I asked the question to people all over the world and the answer was that 304 ss was fine.

[Denver Distiller]

......all my ss tanks are 304. Some of the tanks are almost 30 years old but still in great shape.

Tough to beat 25+ years of experience w/ equipment, thanks for that.

[JohninWV]

Thanks y'all.

[doggman007]

I've worked in the distribution of stainless steel and non ferrous metals in the past and found that 316 is mainly used as a high grade marine resistant S/S

[smaug]

An estimated 90% of all ethanol plants in the US use 304

[Roger]

One caveat to this discussion: there appears to be a difference in SS, depending on what country it comes from. I was in Canada talking to a distiller last week about his tanks that the ordered from China. He told me that he went to China and picked the supplier himself, because he wanted to guarantee the quality.

In his process he was made aware that Chinese 304 is not the same as US 304. He was told this by the Chinese manufacturers, not somebody in the US trying to trash the Chinese products. The firm he ended up going with produced his tanks out of 316, because they said it was much closer to US 304.

Food for thought

[pressure9pa]

ASTM A666 is the most common standard for chemistry and temper for flat rolled stainless steel. If you are questioning the manufacturer's interpretation, you should ask if the chemistry conforms to this standard. 7-9 percent nickel and 16-20 percent chromium is what you're after.