What impurities does the sacrificial run get rid of?

[Stibnut]

I'm wondering - when we run a sacrificial run following a vinegar cleaning run on a new or re-soldered still, what toxic substance(s) are we actually getting rid of? And why must we sacrifice it rather than treating it as low wines and rerunning it?

I get that there may be metal salts, especially copper acetate, released during the vinegar run. Also, there may be other metals from the solder, especially tin, that might also leach in. But salts aren't volatile at all, so a redistillation would take care of them.

The only thing I can think of on the latter question is that perhaps there may be residual organics from soldering flux that would dissolve in ethanol but still have a high enough volatility when redistilled to contaminate the final product. Is this the reason for it?

Please don't think I'm advocating doing away with sacrificial runs. I am just curious about the details of how a sacrificial run improves the safety and purity of subsequent runs.

[CopperFiend]

You got it in one. It's the nasties from the solder that arent soluble in vinegar that are soluble in ethanol. Thus the distillate from a sac run contains these nasties that are bad for living things. These are therefore best thrown away. As they are soluble in ethanol, there is a decent chance they would come back over if redistilled. It's not worth taking the risk.

[NZChris]

They are nasties that cause the body to try to empty itself from both ends. If you try drinking it, take a barf bucket with you when you get the first urge for a crap.

I've seen a couple of posts by newbies that got caught out.

[Oldvine Zin]

I'm wondering - when we run a sacrificial run following a vinegar cleaning run on a new or re-soldered still, what toxic substance(s) are we actually getting rid of? And why must we sacrifice it rather than treating it as low wines and rerunning it?

So you are spot on about the residuals of the flux, in normal potable water it's not such an issue but add some ethanol to the mix and you have a potential safety risk. Another concern is what ever machining oils that are still in the still, remember distilling is all about separating and concentrating
compounds.

Stay safe and read
OVZ

[zapata]

Liquid water soluble fluxes like stay clean are a freaking dream to rinse out. I don't religiously vinegar and sacrifice every time I make small modifications. But I bench clean like a mofo.

[kiwi Bruce]

The real "baddie" is Zinc chloride, it's in most solid fluxes and is VERY toxic. Protect your liver and kidneys from this shit. It's carried in a petroleum jelly base which can be washed with any good solvent. An Ethanol sacrificial run is popular here on HD forums as it's cheap and easy to do.
The liquid fluxes are fluoride based and are easy to remove with steam or just boiling water. The vinegar run can just be a wash, it's use is to "passivate" the copper, not to strip the flux. so doing both IS advisable...Kiwi