Tinned copper pot still

[Revival Stillworks]

I have recently been working on a copper pot still that is over 100 years old and the interior of the still is coated with a layer of hand wiped tin. I didn't realize that this was a common practice on stills back in the 1800 and early 1900. I spoke to a distiller friend about this and apparently it was common on many stills back then. Does any one have any more information on this practice, when and why it was done, or have an old copper still that has been tinned on the inside. If you would share a picture or two that would be great. I am currently exploring ways to refurbish the still but the tin is an interesting challenge. 

 

[AnthonyM]

So stateside there are several companies that do tinning on copper pots and pans. https://eastcoasttinning.com/ might be able to answer some more specific questions. Proper PPE and not poisoning yourself from tin fumes would be top on the list.

As to why it is probably the same as it was for pots and pans. Wouldn't want to leech out copper into your food or have your still get eaten by acidic washes.

[bluestar]

Tinning should not be necessary for a still anywhere BEFORE the final path of vapor going into the condenser, since copper salts should not come across in the distillate. It could make sense to do so in the lyne arm and condenser, on the other hand. But if someone planned to distill relatively acidic materials, tinning might have been employed to reduce erosion of the copper. And inferior copper might be more affected by erosion. On the other hand, if the still was built from parts manufactured for other purposes, it might have been tinned for general food use. Did you verify it was tin? Thin layers of solder on the interior is not unlikely if solder joints were used. If soldered, check to be sure it was not lead solder.

[PeteB]

Way back when your still was built the builders probably didn't know copper contact with distillate vapour is very important to remove undesirable compounds, mainly sulphur. As mentioned above it might have been done to prevent erosion of the copper. Erosion of copper in a still shows the copper is working for you. I suggest you try to remove the tin from anywhere in the vapour path. In the pot it won't matter if left.

[Dan P.]

On 3/4/2020 at 3:11 AM, PeteB said:

Way back when your still was built the builders probably didn't know copper contact with distillate vapour is very important to remove undesirable compounds, mainly sulphur. As mentioned above it might have been done to prevent erosion of the copper. Erosion of copper in a still shows the copper is working for you. I suggest you try to remove the tin from anywhere in the vapour path. In the pot it won't matter if left.

Exactly, it was probably made by a bloke who was a pot and pan maker rather than a still maker, and he might have tinned it because it would have seemed odd not to.

It would definitely be worth checking it for lead, though. The used to put it everything!
 

[Southernhighlander]

On 2/16/2020 at 9:39 AM, bluestar said:

 But if someone planned to distill relatively acidic materials, tinning might have been employed to reduce erosion of the copper. And inferior copper might be more affected by erosion. On the other hand, if the still was built from parts manufactured for other purposes, it might have been tinned for general food use. Did you verify it was tin? Thin layers of solder on the interior is not unlikely if solder joints were used. If soldered, check to be sure it was not lead solder.

Bluestar,

 

I think that you may be right about the acidity.  i just had a customer the other day ask if we could line the inside of a stainless still with PTFE because they will have some highly corrosive chemicals in the pot.  They are not distilling beverage ethanol.

Also lead solder was used in still pots in the old days.  Normally they only used it in the pot or in the upside of the vapor path.  Only idiots used it in the condenser or down side of the vapor path, for obvious reasons.  They believed then that the lead could not climb the vapor path.  I can't say either way and I would certainly never use it on any part of a still or drink anything from any still where lead was used in any way.

[bluestar]

On 3/9/2020 at 2:57 PM, Southernhighlander said:

Also lead solder was used in still pots in the old days.  Normally they only used it in the pot or in the upside of the vapor path.  Only idiots used it in the condenser or down side of the vapor path, for obvious reasons.  They believed then that the lead could not climb the vapor path.  I can't say either way and I would certainly never use it on any part of a still or drink anything from any still where lead was used in any way.

Interesting point about the lead. Unfortunately, there are some lead-organic volatile compounds, that perhaps could be created during distillation (specifically tetraethyllead, what they used to add to gasoline). While the amount that might come across is very small, the toxicity of the lead is far worse than for any copper-organic compounds.