Sulfite “SO2” effect on distillate

[BrewinBrian44]

Something piqued my interest in another thread that Jonnyspirit brought up.

There were comments about sulfites “potassium metabisulfite” being added to fruit must and the effect they have on the final distillate. He mentioned something I was unaware of. Unlike hydrogen sulfide, which can be removed by reacting with copper, Sulfur Dioxide cannot and will remain in the spirit. This got me down a little research rabbit hole.

Indeed, he is correct! This is a problem that emerges when distillers run failed wines that have high amounts of sulfites added to them. Their presence in the distillate creates an intense burning sensation on the nose. From a thread I read in the ADI forum, this seems to be most concentrated in the heads and possibly early hearts as brandy cuts lean in this direction. It levels off the closer you get to tails. It can be removed with a few different techniques, one being adding a measured amount hydrogen peroxide to the low wines, which will also remove any remaining sulfides as well. Doing more HD reading about the addition of hydrogen peroxide to sulfited low wines revealed a very heated discussions about how unsafe it is as it can create a dangerous exothermic reaction in the presence of SO2 and other compounds commonly found in our distillate.

This got me thinking about a recent apple brandy I just made. In total, I used about 30 gallons of fermented cider to make it. Part of it was donated from a buddy. He gave me 10 gallons of old cider he never got around to bottling. It was about 2 years old and part of it looked to be a little oxidized from a rubber bung that fell off the carboy. His cider was treated with metabisulfite in two steps. The first as a pretreatment to the raw cider must to kill any wild microbes that may be present, the second time as a preservative, post fermentation with potassium sorbate as well to prevent re-fermentation upon back sweetening. The sulfite additions were done to the exact dosage suggested on the back of the vial, no more, no less. The other 20 gallons that I fermented had no sulfites added.

Here’s the rub. When I performed my spirit run from combining all these low wines, I was shocked at how pungent the heads jars were. They didn’t really smell bad, but rather burned the shit out of my nostrils, unlike typical heads or high proof ethanol. I couldn’t explain why this would happen and thought it came from an infection that took hold it my 20gal ferment. The intensity of this burn faded as the jars progressed, exactly how it was described in the ADI forums. I believe I found my answer

I let these jars air out for a day and this burn on the nose greatly subsided. Most of my hearts jars had none of this on the nose, but I did dip into early heads in small 20ml quantities to pop over some extra apple flavor and aroma. My final blend that went into jars with oak does not burn my nose and I feel like I nailed the cuts. Now, with all that said, am I safe with this spirit? Will I cause health problems to myself or others by consuming it? Doing more reading about SO2 shows that in high doses, it’s pretty bad for people. Distillation definitely concentrates it, but I have no idea how much is in my spirit as it shows up more early in the run.

Final note: If this thread does nothing but provide caution to any novice distillers wishing to add sulfites to their products, I’ll be happy about that. Don’t use it! Thanks Jonnyspirit for enlightening me!

https://mdpi-res.com/d_attachment/foods ... 1667964486
Here’s an interesting read on sensory analysis results of sulfited and non-sulfited wines that were distilled into brandy with gas chromatograph data on the total chemical makeup of the sprits. Some of the data is not related to my topic, but also very interesting. Backs up the mantra that double distilling brandy with a potstill is the superior method.

[Steve Broady]

I don't have an answer for you, but I'm definitely interested in learning more. Early on in my hobby, I distilled a whole bunch of commercial wine that was otherwise going to be thrown out. It had that same burning sensation, which I assumed was just heads and my lack of skill and experience. Over a year later, it has a lot less of that, but it's still not an especially amazing brandy. Hopefully we'll learn something together.

[NZChris]

I'm not an expert on removing it because my research told me not to use it and I haven't accepted the challenge.

[Dougmatt]

Funny how topics come in waves. Having similar conversation in another thread led me to look into this as well. There is a Chinese CN on removal of so2 I found here: https://onlinelibrary.wiley.com/doi/ful ... 02/jib.100

Which suggested distilling and using activated carbon in the hot distillate to remove. They tested three ways including h2o2.

[Steve Broady]

That’s really interesting. So it seems like there might be a good reason to carbon filter brandy made from wine which has been treated with sulfites. I may have to try this.

[BrewinBrian44]

I'm not an expert on removing it because my research told me not to use it and I haven't accepted the challenge.

The topic should really be geared towards people that acquire wine or cider they did not ferment that has sulfites added. Like in my case. Again, don’t use it is the best recommendation.

One of the guys in the ADI forum said his heads cut almost knocked him on his ass from taking a whiff.

[Dougmatt]

Not positing this to be argumentative rather to clarify my own thoughts. I have removed all chemicals from my wine making process over the years except kmeta so I’m trying to get a real sense of what this means.

I agree on don’t use it if the intent is to make brandy, but its generally accepted process that wine intended to be aged for any length of time should have it. Also many of the “things”people on this board ferment washes out of already have it in there. (Commercial cider, purchased grapes / juice shipped from the farm etc) so it is already there.

Too many people of the “I don’t use sulfites” crowd are all over the wine making forums asking why their wine tastes flabby or flat after a few years…. The prevailing opinion and the industry is that’s caused by a lack of sulfites….

I age my red wines at least 1 year in barrel and 1-2 years in bottle before starting to open them. In some cases, I may decide to Brandy them as I just don’t like drinking them so this is a good thing to know about. Basically I make my wine with the intent for it to be good wine and plan to only make brandy with wines I’m not enjoying so I personally will continue to use it as I’ve always done. I’ve made brandy 3 times now from wines that had kmeta added at bottling and have detected none of these issues in the heads. The last brandy I made won a blind taste test amongst some wine drinking friends versus commercials so either they all like bad smells or it wasn’t an issue for me.

Also as I seem to understand it, SO2 is created when there is free O2 to scavenge and react with.. I’ve read on the ADI board where people are saying this “situation” is often in oxidized wine as well which seems to indicate that’s the source of the “biggest” problems.

I’m still researching and open to change but for now will continue to use it when I am making wine to age and enjoy as wine as any change I make now won’t be felt for a few years.

Edit: research also seems to indicate most of it comes off very early so it’s generally in the heads which of course is where a lot of the brandy flavor is….

[BrewinBrian44]

Funny how topics come in waves. Having similar conversation in another thread led me to look into this as well. There is a Chinese CN on removal of so2 I found here: https://onlinelibrary.wiley.com/doi/ful ... 02/jib.100

Which suggested distilling and using activated carbon in the hot distillate to remove. They tested three ways including h2o2.

Fantastic read! Thank you. Nice to have some quantitative data to back up the treatment methods.

After reading though, it seems clear the best course of action for one who intends to ferment a wine to be distilled, again, is to simply not use sulfites. This paper confirms what it does do a spirit. I didn’t get the matchstick aroma, rather just the burn. Almost like the sensation of smelling what’s coming off the still from a vinegar cleaning run. Like you’re literally breathing in acid.

Also, the treatment methods other than activated charcoal look like they destroy a lot of desirable acids that we need as precursors to react with oak to create a complex spirit. There is also a huge reduction in esters.

[Bitter_Brew]

Wine here is an order of magnitude cheaper than I can buy grapes or grape concentrate, and I like brandy and other distilled grape spirits.

Here is the results of my research:

If you put sulfites in wine, it's not removed by copper. This is clear.

Most bulk white wines here probably have 100-200ppm of sulfites. This can be removed (theoretically, at least) by the application of 4-8mL of 30% food grade H2O2 to 25L of wine (according to this calculator: https://www.winebusiness.com/calculator ... g/calc/22/). The result could be tested with sulfite testing strips. This article (https://www.agrar.steiermark.at/cms/dok ... 011-03.pdf - German) says that this method adversely affects the flavour.

I read on a forum post (https://adiforums.com/topic/3329-sulfites/) that raising the pH to 5.8 before distilling will reduce the sulfites. This is backed up in the same German article linked earlier, with reasoning. So I could do the sums and dump some CaOH (or NaOH) in to raise the pH, which would drop out the sulfites as calcium or sodium sulfite. Overdosing will lead to an alkaline or soapy taste, unsurprisingly.

I might try the second option because I already have food grade CaOH. I will try to remember to report back when I get a chance to do it.