Plastic Conical Tanks Question......

Can someone explain the specific gravity statement below and if this conical tank would work for a fermentor?

DRAGGER.....

15 Gallon Full Drain Mix Tank With 60° Angle Base
Selected as supply tanks for application systems and several allow for complete drainage. Require stands to support conical bottoms. Medium density polyethylene with U.V. inhibitors and designed for containment of liquids of up to 1.7 specific gravity. Walls are translucent for level viewing, and equipped with gallon indicators. Meets FDA standards. Max. temp. 120° F constant, can spike to 140°F. All tanks have a 12” screw on lid except #8696 which has a 16". All tanks have 2” polypropylene bulkhead outlet installed with EPDM gasket, exceptfull drain tanks which have a 2” polyethylene MPT. Distance from bottom of tanks to floor is approximately 11” on all tanks. Stands are polyester powder coated

$68.82

http://www.usplastic.com/catalog/variant.asp?catalog%5Fname=USPlastic&category%5Fname=20726&product%5Fid=3863&variant%5Fid=8784

The S.G. of anything you may brew/ferment will range between .9XX and 1.1XX(well within limits1.7XX). The conical you are looking at will definitely work for brewing. Don't forget though, the 2" ball valve will cost you about $30 for brass, a LOT more for SS.
They have good prices, Ive been looking at them for a while. I hope you're closer than me, shipping was about $100 to get it to PA.
Oh, yeah, make sure it comes with the stand. Dont assume that because it says "Stands are polyester powder coated" that it comes with a stand...
Please, let me know if you do follow through. I'm still very interested in one of these conicals from USPLASTIC.COM

The shipping is $26.51 to my zip code.... I was thinking about a PVC valve and reducing the size from 2" down to 3/4"..... They have an online chat to ask questions I will hit them up and ask about the stand..... During the week.....

EDIT: I have sent an e-mail to them questioning about hte stand being included with the tank.....

DRAGGER.....

Actually if you go to this page http://www.usplastic.com/catalog/product.asp?catalog%5Fname=USPlastic&category%5Fname=20726&product%5Fid=3863

it shows you mulitple sizes and the cost of the stands. When I get the money, this is the way I am going until I can afford the Stainless. I think as long as we are careful with the cleaning, these will work just fine.

John

Nwcw2001 said:

Actually if you go to this page http://www.usplastic.com/catalog/product.asp?catalog%5Fname=USPlastic&category%5Fname=20726&product%5Fid=3863

it shows you mulitple sizes and the cost of the stands. When I get the money, this is the way I am going until I can afford the Stainless. I think as long as we are careful with the cleaning, these will work just fine.

John

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Thanks,
I am looking at $186 and some change to get the tank and stand to me.... might be worth the extra money to just go stainless OR build my own stand as 78 bucks for that little bit of metal is HIGH.... I have all the metal working tools to build a motorcycle to include the frame I think I can handle this stand.....

DRAGGER.....

I have said this before on pages, I would look for a Norwesco distributer near you and order a induction tank (conical) from them...their lids seal significantly better and I have heard better results from them...

RockfordWhite said:

I have said this before on pages, I would look for a Norwesco distributer near you and order a induction tank (conical) from them...their lids seal significantly better and I have heard better results from them...

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Better results? Please explain.

I think the lid thing is negligible because of the thick layer of CO2 that protects the wort.

DRAGGER said:

Medium density polyethylene with U.V. inhibitors and designed for containment of liquids of up to 1.7 specific gravity.

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I am guessing that they simply have not tested the product with any alcohol levels higher than that.

PE is pretty tough stuff. It can take straight 100% ethanol and lots of other VOCs. IT's a common material to use when manufacturing laboratory bench top squirt bottles which get filled with all sorts of things.

What the material will do is leach polyethylene molecules from the surface into any fluid inside, which will produce off flavors. You'll smell most strongly when you first open the vessel up.

You can get the majority of it out by filling it with hot water & vinegar and letting it soak. After that, it'll only impart a slight flavor component.

It is a fact of materials sciences that all material have a vapor pressure. Diamond, gold, quartz, steels, the neighbor's cat, all polymers, - all materials have a vapor pressure. Material such as zinc, cadmium and plastics have enormous vapor pressure. Zinc and cadmium have vapor pressure so high that when plated on steel they can protect the base metal even when it's scratched because the atomic particles of the plating floating in the air (desorbed from the surface) a few molecule's distance high, tend to sublime back to the surface filling the scratches in the plating before ozidation can set in.

So you will always have polymer in your brew when using plastic.
I ain't saying that's a bad thing. It's just a fact.
Lots of people have good experiences using plastic fermenters.

If I were looking at a polymer solution I'd get those clear plastic PET fermenting carboys. They are cheap and tend to impart zero off flavor - at least none that the human can detect. PET is the material that soda bottles are made from. It's used exactly because it is so utterly flavor neutral and tough. Polyethylene is not flavor neutral.
http://www.homebrewit.com/aisle/1041
If I were not planning to go SST I'd probably junk my glass carboys and get a few of those. Safer, way far safer than glass.

And for those who absolutely friggin HAVE TO HAVE a conical.
Those PET carboys can be inverted and fitted with a valve ( or a long hose with a plug).
And you can have more than one happily fermenting at a time 'cause they are so cheap.

http://brewery.org/brewery/library/BrewCapKB.html

Cliff897 said:

You can get the majority of it out by filling it with hot water & vinegar and letting it soak. After that, it'll only impart a slight flavor component.

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So slight that it's negligible, esp. with the money saved.

DRAGGER said:

Can someone explain the specific gravity statement below and if this conical tank would work for a fermentor?

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The specific gravity statement relates to the strenghth of the tank. As it is plastic, it can only handle a given amount of weight. Not a problem at all w/ wort type gravities.