Greenish/Yellow Heads in brandy from Red wine

[JustAndy]

We are having a problem which has left me scratching my head a bit. 

The fores, heads, and early parts of the heart are coming over with a pale greenish/yellow tint. It starts most intense at the heads and generally lessens as the run goes on. It looks different than the copper contamination I've seen from other stills, there isn't any blueish and shades more towards yellow. We've done 6 distillations of wine and it has happened the same way each time. 

We are distilling a 14% abv red wine made from Syrah, the wine has no added SO2 and doesn't present as flawed (no obvious VA,brett, infections). Wine pH is ~3.8 

We are running a 4 plate Kothe still; it has a copper boiler, stainless column with copper plates and dephleg, and a stainless steel condenser. The lyne arm to condenser is stainless and has an upward J, so liquid generally drains back to dephleg and not condenser. It is heated very slowly via bain marie and no wine generally boils/foams into the plates. 

We generally distill brandy in a single pass, using the plates and dephleg with a heads cut from 182 to 175, adjust dephleg down and a hearts cut 165-145. The still is cleaned with 80C water after every distillation and receives a citric acid rinse generally when we switch between products or the copper is looking tired. We've distilled probably 300+ runs of wine on this still without encountering this.

I've tried degassing the wine to remove co2, which didn't change anything. I gave the still a through cleaning & citric acid treatment, as well as dissembling the lyne arm to look for corrosion or debris but it looked clean. Adding baking soda to the diluted greenish fraction doesn't alter the color, but after a period of time it appears some of the green drops out and the fraction is clearer when decanted. Today I am going to redistill the greenish portion as well as try filtering it through a .25 micron filter to see what happens but I would appreciate some theories on what's going on.   

[JustAndy]

Redistilling the green fraction without any wine in the still didn't produce a different result. It seems unlikely it is copper related, so we are investigating it possibly being diacetyl. There isn't an aroma or flavor component to it that I can detect, but the aroma of heads might just make it hard to seperate out. 

[Silk City Distillers]

Diacetyl has a very obvious/unmistakeable aroma and flavor, and the thresholds are very low.  If there was enough diacetyl to impact the color, I would imagine you'd be swimming in cheap buttered popcorn.

 

[JustAndy]

That was what I thought as well, but it was suggested by our local pHD in whiskey at Oregon State so we are exploring it. It was also mentioned by Meerkat in another thread who said "The closest I have seen to your experiece was a yellow-green heads stream in a continuous neutral spirit plant. The plant wisdom was that this was diacetyl (butanedione). In this plant the fermenters were steel, the stripper column mostly copper and the rectifier fully stainless steel." 

We didn't ferment this wine, but the winery mentioned the grapes were not in good shape compared to their usual material so perhaps it is a fermentation byproduct issue? 

[SlickFloss]

Can you show pic of your distillate? Are your dephlegs guts copper? How big is your boiler and can you fit inside of it? We had some similar issues a while back during our commissioning process we got all types of wild colored distillates if you wanna talk through some of our solutions

[SlickFloss]

Also, if you go deep into tails, it sounds like you're not doing stripping runs but it would also happen very late in a strip if you go low, are you getting black fatty/waxy/ashy residue coming through? Do you run a parrot/spirit safe? 

[JustAndy]

The dephleg I believe is all copper. The boiler is about 300L, so too small to get inside but you can reach everypart of it from the manway. 

I will try to post a picture, the color tint is light enough that it is very hard to photograph. 

When running out the tails eventually the spirit is very waxy/oily, but nothing black, ashy, flecky. It looks just like tails from other washes, there is no color in the late hearts or tails. We have a parrot, which actually designed with a sort of phlegm separator which holds back wax and etc which floats at the top.   

I distilled a different wine (chardonnay) and the distillate has no color tint, which leads me to suspect some kind of fermentation/nutrient byproduct from the syrah wine rather than something from the still.   

[SLCDBD]

Just a hunch but what did you distill prior to the runs with the greenish-yellow tint?

Sometimes I notice that wacky colors come out in the heads when I'm doing a run immediately following a stripping run where I went to 0% ABV. My hunch is that the weird colors may be fores/heads dissolving the fats that deposited in the condenser at the very end of the previous run.

I can make this go away by doing a quick steam run to clear out the condenser most of the time. Maybe try steaming out your condenser before your run and see if that helps?

[MDH]

If it were that, he'd be getting it from every run.

What was the vinification method? Do you make the wine or does someone else? Ask them about maceration times. It could be a volatile component from maceration with grape seed.

[JustAndy]

In between various distillations of the syrah we distilled pear mash, rye mash, and chardonnay wine none of which had any color tint. The syrah had a tint regardless of the product run before it, and steam cleaning/flushing/citric rinsing prior to distilling the syrah had no impact on the tint. 

We didn't make the wine, I am going to follow up with the winery to get some more details about the process. We've distilled a lot of other wine for them, and they are an extremely well-regarded winery but it seems like it must be some artifact of the wine making process. If it was something related to grapeseed/maceration, it seems like it would also be a problem when distilling grappa as the pomace is rarely deseeded before distillation but we've never had a tint to the grappa from red wine. 

We sent the tinted fraction in for copper testing, which showed only a normal/nominal amount of copper so that is ruled out. With time, there was some sediment that started to form and settle out, which seemed to reduce the color of the tinted fraction. Based on that, we ran it through the fine depth-filter pads we use pre-bottling and that removed all of the color. Mysterious.. 
 

[MDH]

Let me know how it goes, Andy.

[SLCDBD]

Depth filter pads are sometimes packed with activated carbon...

 

if your pads are carbon-free, then that would be very strange for the color to be filtered out...

 

weird.

 

[Donbroadbranch]

Did anyone ever get to the bottom of the tint? I have a similar problem with a rum run. We will be sending sample in for testing. We do have buttered popcorn aroma, so diacetyl could be the culprit. Light green/yellow tint.

[JustAndy]

I never really got a satisfactory answer about what it was, a sample left to settle eventually has the color fall out though and we were able to filter out the color with a pad filter. Once the color was removed it was difficult to note any difference between a typical, non-colored run. We've had it happen a few other times (maybe 20 times out of the 6000+ runs on this still), it is hard to come up with a commonality as it's happened with apricots, pears, and red wine. A winery client thought it might be a byproduct from incomplete malo-lactic fermentation which made some sense in a few of these contexts.