Brass dip tube on stainless kettle

[Newts]

Hey guys,

This seems to be a common setup but I'm getting confused when people say they have to buy certain types of brass to be food safe and considering I'm going to be using it for boiling my wort I'm wondering what I'm looking for in terms of brass.

Can i just go to Bunnings and get one of their compression fittings? The ones I seen in there have black specs throughout that didn't look like they should be going into a boil and didn't have any paperwork attached to them to say what standard or type of metal they are. I've got two big stainless steel rigs setup and I just need the dip tubes on them to finish them off.

Any thoughts?

Cheers,

Newts

 

[Cocko]

Thoughts?

Get stainless PU's.

2c.

 

[pk.sax]

Those fittings are stamped with an Australian standard and are potable water safe. I've used them, will do again. No side side side side side side side effffects. Can always pick the chrome plated ones if you want.

If ur really paranoid, read up on how to brew's brass pickling.

 

[Online Brewing Supplies]

I think the point people push is at lower pH levels (mashing/boiling etc) Brass can leach out none desirable metals.
I dont have an hard evidence to present but I would look into it if you really need to use brass.
BTW I have SS pick ups on the site .
Nev

 

[QldKev]

I've used brass on my original system for a few years, even on my current system I have a couple of brass fittings left that I need to change over. Also hot water systems have been plumbed with brass for many years. But if you want stainless, which is nice and a lot better for cleaning, ebay is a lot cheaper.

 

[adryargument]

Mmm,
As Nev said, stainless is inert at all PH levels. I am under the impression that copper and brass tend to leech more in certain situations. Water is quite friendly, however wort is a totally different beast.
Also, the maintenance on brass and copper is so much more cleany.

Buy stainless just for the ease of cleaning and you can throw anything at it. Edit: even the cat!

 

[Feldon]

My understanding is that the "black specs" on brass fittings is lead. You don't see it where the fitting has been machined (eg. to form threads). Machined surfaces show that beautiful buttery golden colour.

Brass is an alloy of copper and zinc. In manufacture lead is added to molten brass because it melts at a lower temp than the copper and zinc.

When the molten metal mixture is injected into the die (or mold) to form a cast of the fitting, the copper and zinc solidify first and their atoms arrange themselves in a repeating matrix with no space between the atoms for the lead, which is still in a liquid state. So the lead is forced to the outside of the casting. This where it fufils the reason why it was added in the first place. It acts as a mold release agent ensuring that the fitting does not stick to the tool steel of the die. The casting is easily ejected as the lead finally cools and soldifies on the external surface of the casting, leaving a black discolouration. (spray on mold release compounds are used too and may contribute to the discolouration)

What this means in brewing is that exposing your hot wort to machined surfaces of a brass fitting (where the lead contamination has been cut or drilled away) is probably OK. But exposing wort to extenal blackened surfaces (eg. a brass hose barb on a false bottom) risks getting the lead on the surface into the wort.

It is often said that there is only a tiny percentage of lead used in the brass casting, but be aware that this small amount can end up concentrated on the external surfaces. As has been said, Palmer's book How to Brew (free online) details how to remove the lead from the surface by a pickling process.

 

[Fat Bastard]

We might be playing metallurgical semantics here, but lead is commonly added to brass to make it easy to machine rather than for casting purposes. It's easy to tell which brass has lead in it because the chips from machining are short, rather than long and curly. Most brass fittings will be of the high speed machining type (i.e containing lead) because they pretty much have all had some sort of machining operation performed on some sort of automatic or CNC machine in volumes where speed is of the essence.

Pickling as per Feldon's reference to Palmer will remove it from the surface, and I believe there's some positive effect to be had from having some copper in your system.

 

[thebeemann]

For $6.95 for a stainless one from Gryphon brewing why would you take the chance on other metals ?

 

[Newts]

Yeah, I think everyone would use stainless if they could. I tried everywhere in town to get stainless compression fittings and no luck. I can't even find these on your site Nev, found the pickup tube though.

Hmm, I think I'll get this brass rig going then upgrade to stainless at some stage. Otherwise it'll never happen. Had the brass soaking in vinegar overnight which cleaned it up fairly well. Inside still doesn't look quite right yet. I'll "pickle" the compression fittings and go from there.

 

[Online Brewing Supplies]

Yeah, I think everyone would use stainless if they could. I tried everywhere in town to get stainless compression fittings and no luck. I can't even find these on your site Nev, found the pickup tube though.

Hmm, I think I'll get this brass rig going then upgrade to stainless at some stage. Otherwise it'll never happen. Had the brass soaking in vinegar overnight which cleaned it up fairly well. Inside still doesn't look quite right yet. I'll "pickle" the compression fittings and go from there.

PM sent re: compression fittings.
Nev