Distillation of sulfur dioxide containing ingredients

[Brewstilla 0]

We are starting some R&D on a product that involves the redistillation of a base spirit with other ingredients, including some fruit. For ease, consistency, and fruits not available in our locale, I would like to use dried fruits. After some research, it seems the vast majority are packaged with SO2. 

So my question is, will the SO2 come over in the spirit like many other sulfur compounds? I am guessing that this will be the case, and is easy enough for me to trial on the benchtop still, but figured I would throw it out here first to see if anyone had any experience or input before doing that.

Thanks! 

[Silk City Distillers 233]

Sulfur dioxide will come over, you will need to treat.

https://onlinelibrary.wiley.com/doi/full/10.1002/jib.100

[PeteB 57]

I did some very interesting distillation of sulfured wine a couple of months ago.

Some bulk wine was double distilled at another distillery using simple pot still. The sulfur fumes on the first run were very strong. Calculated additions of H2O2 were made during the run to help knock it out. More H2O2 was added during the spirit run.

I did the stripping run of my share of the wine through my continuous copper stripping column. No H2O2 added. Very surprisingly there was no sulfur smell and a test of the sulfur level in the low wines was low. We did add some H2O2 during the spirit run to clean it up a bit more.

The hot feed wine splashes down over copper plates, and vapors move up over the plates in the stripping column. Maybe the sulfur in the hot liquid feed wine reacts much better with the copper. In a regular pot still the sulfur/copper contact would mainly be vapor.

 

 

[meerkat 21]

I think @PeteB is correct regarding the reactions being faster in the liquid phase.  I have seen large continuous vodka columns which were made of stainless steel, but the reflux was passed through a bed of copper raschig rings before returning to the column.

Edited November 17, 2020 by meerkat
typo

[PeteB 57]

I did read somewhere, possibly on this forum many years ago, that silicon based antifoam will coat the copper surface and reduce interaction with sulfur !!

Does anyone know if this is true?

[JustAndy 22]

My experience with antifoam is that it fouls the still much easier than normal; the coagulated muck it creates cooks onto the hot copper and it makes sense that this forms a physical barrier which reduces copper interaction.  

The level of so2 allowed in dried fruit is something like an order of magnitude greater than is typical in wine, but I think whether it's a problem in redistillation will really depend on how much you use.