Possible sulphur issues in an apple brandy

[NormandieStill]

Back story: Last year was not a great apple year around here, but we did manage to press 160 litres of apple juice into a wooden cider barrel to make calva. After a little experimenting the year before I had found that the ferment using the natural yeast on the apples, produced the most flavourful (albeit lowest yield) low wines. So this year we decided to run the whole batch on natural yeast. Fairly early into the ferment I could smell some sulphur, so (as I had the previous year), I fed the yeast some nutrients, and while the smell didn't go away, it stopped getting worse. The previous year I had dumped a copper tube into the bucket which seemed to clear up the smell, but this year it had already faded when I came to distill so I didn't think about it. My still is stainless, but I have a bunch of copper pieces in the boiler, a roll of copper mesh in the vapour path and a copper condenser, and I've not noticed any problems in the past.

The problem: While I was running the spirit run, I would take a few drops on my hand and rub them together. The residual smell when the alcohol had evaporated was not very pleasant, a little like the smell on your skin the day after you've been chopping onions or garlic. I wondered if it was just the alcohol bringing out a smell that was already on my skin.

I've now tried three times to blend my jars, and that damn smell is everywhere. It finally more or less peters out about 4 jars from the end (the last two jars came off very cloudy so I called it quits). The cuts are proving to be a nightmare. I can smell and taste differences between the jars, but the smell (and a harsh burn that I associate with it now) covers everything so I've no way of knowing what's going on.

As of yet, I've not touched the backset, so while it is depressing, the option remains to just dump everything back into the boiler and start again, but if this is a sulphur problem I don't see how a rerun will make anything different. I did see a reference in an old thread to using hydrogen peroxide on the low wines to clean up some more persistent sulphur compounds. Has anyone tried this?

Has anyone had a similar problem in the past? Will it age out if I can crib together a blend from abv and trying to find the flavours under the onion? This is the biggest run I've done yet, and I've got about 12 litres of distillate from which I was expecting to pull somewhere between 4 and 6 litres of hearts (based on prior efforts). Given the work involved, I don't really want to bin this if there's some way of salvaging it.

HELP!

[TwoSheds]

Don't know about it at your stage, but I've certainly encountered a strong sulphur smell when fermenting hard cider and cyzer. (Google 'cider rhino farts' for more info) It tends to pass and not be present in the final product, but that obviously wasn't the case for you.

I'll be curious what others say.

Good luck.

TwoSheds

[MooseMan]

It is possible that you could have liberated some metal salts while storing/fermenting/distilling the acidic cider?

I'm not saying you did, but this sentence:-
"I would take a few drops on my hand and rub them together. The residual smell when the alcohol had evaporated was not very pleasant, a little like the smell on your skin the day after you've been chopping onions or garlic"
Rings a bell somewhere in the back of my head from a past life in metallurgy, even though sulphur is non metallic.

If it's that persistent, I can't see how you'll be able to save it as a brandy, but you could try raising the pH and diluting with a ton of water to split the sulphate away, (I'm totally making an assumption here that ester Hydrolysis works on sulphite/sulphate) then running through a reflux for neutral?

[shadylane]

I'm almost a total newbie at making apple brandy.
It sounds like this years natural yeast and apple juice didn't get along.
Was this years apples lower in sugar and more tart than before? Was the weather different?
Was there more or less of a yeast blush on the apple skins? Was there something else different that didn't get noticed?

Sulfur character makes me think nutrient and pH levels lower than the yeast preferred.
According to a friend that makes brandy, whom I like to argue with.
"Wild yeast can be a crap shoot, for consistency, pitch a big dose of K1-V1116.
K1 and other killer strains of yeast are more forgiving of low nutrients, pH and will outperform, then cannibalize the remains of wild yeast"

[tommysb]

A thought about the *possible* source of sulphur notes in the ferment, Normandie - although not about why they got worse with distillation.

In winemaking, ageing on lees is considered 'reductive' and will lead to reductive notes - e.g. struck match, gunpowder, sulphur, cabbage.

I don't actually think this is the source of your highly sulphurous notes as you mention that they came in early in the ferment.

But looking into lees and its affect on sulphur notes at very least might make some interesting reading for those interested.

[Tedd squirrels]

Distill your spoiled distillate with the addition of refined, deodorized, frozen, tasteless and odorless vegetable oil. Create a film of oil over the surface of the distillate 0.5-1 cm and distill in simple distillation mode, you don’t even need to select the heads. You will be pleasantly surprised.
Using a similar method, I forced my colleague to correct his defective distillate. The cleaning was successful, the colleague is happy.

Video without translation. But the point is that the defective Rumbon (Rum + Corn) was saved by distillation with oil:
https://dzen.ru/video/watch/65bc8ece44aac560d29053a2

[NormandieStill]

I'm almost a total newbie at making apple brandy.
It sounds like this years natural yeast and apple juice didn't get along.
Was this years apples lower in sugar and more tart than before? Was the weather different?
Was there more or less of a yeast blush on the apple skins? Was there something else different that didn't get noticed?

Sulfur character makes me think nutrient and pH levels lower than the yeast preferred.
According to a friend that makes brandy, whom I like to argue with.
"Wild yeast can be a crap shoot, for consistency, pitch a big dose of K1-V1116.
K1 and other killer strains of yeast are more forgiving of low nutrients, pH and will outperform, then cannibalize the remains of wild yeast"

I'm thinking the same. Last years naturally fermented batch was about 1/4 of the total low wines that went into the spirit run. It's possible that the resulting bad stuff was just dilute enough to not be noticeable. I didn't notice the juice to be more tart (the kids were drinking it off the spout of the press!), but I had a hell of a time sterilising some of it for juice. Despite a solid pasteurisation (75-80C for 5 mins and maintained at that temperature while filling), and sterilised bottles, I had about 8 bottles (of around 20) start fermenting and at least 4 developed mould. I should perhaps have taken that as a warning sign!

A thought about the *possible* source of sulphur notes in the ferment, Normandie - although not about why they got worse with distillation.

In winemaking, ageing on lees is considered 'reductive' and will lead to reductive notes - e.g. struck match, gunpowder, sulphur, cabbage.

I don't actually think this is the source of your highly sulphurous notes as you mention that they came in early in the ferment.

But looking into lees and its affect on sulphur notes at very least might make some interesting reading for those interested.

Interestingly, the standard practice for making Calvados is to leave the cider on the lees for up to 6 months. In hindsight I should have dumped some copper into the barrel with the nutrients to eliminate the sulphurous stuff early on. I'll do some reading up though.

It is possible that you could have liberated some metal salts while storing/fermenting/distilling the acidic cider?

I'm not saying you did, but this sentence:-
"I would take a few drops on my hand and rub them together. The residual smell when the alcohol had evaporated was not very pleasant, a little like the smell on your skin the day after you've been chopping onions or garlic"
Rings a bell somewhere in the back of my head from a past life in metallurgy, even though sulphur is non metallic.

If it's that persistent, I can't see how you'll be able to save it as a brandy, but you could try raising the pH and diluting with a ton of water to split the sulphate away, (I'm totally making an assumption here that ester Hydrolysis works on sulphite/sulphate) then running through a reflux for neutral?

The cider fermented in a wooden barrel and went straight from the barrel to the still. But the barrel was not new, and despite a fairly rigorous cleaning protocol (took one head off, pressure-washed the inside and steamed the hell out of it several times for up to a couple of hours - until the outside was hot to the touch!), it's possible that there was also sulphur trapped in the wood. Normal practice here is to rinse the barrel out, clean it as well as possible. Dry it out. And then burn a sulphur wick in it before sealing it up until the next season.

Distill your spoiled distillate with the addition of refined, deodorized, frozen, tasteless and odorless vegetable oil. Create a film of oil over the surface of the distillate 0.5-1 cm and distill in simple distillation mode, you don’t even need to select the heads. You will be pleasantly surprised.
Using a similar method, I forced my colleague to correct his defective distillate. The cleaning was successful, the colleague is happy.

Video without translation. But the point is that the defective Rumbon (Rum + Corn) was saved by distillation with oil:
https://dzen.ru/video/watch/65bc8ece44aac560d29053a2

My gut feeling is that while that may be quite effective, it's going to strip out quite a lot of flavour (I'm guessing the oil acts a solvent for fat-soluble congeners). The apple flavour in apple brandies is subtle enough at the best of times!

After a fair bit of reading on the ADI forum, it seems that the H2O2 treatment is considered the standard solution. I've read and re-read croweater's somewhat stressful warnings on the subject, but the people advocated it's use appear to have done so multiple times without blowing themselves up. I've got 250ml of 3% H2O2 solution and I've tested adding 4ml to a 400ml jar of what are most likely heads, with a sample taken before and after treatment. I feel I can smell a difference (I'm not drinking it!) but I'm waiting for my other half to see if she can tell the difference (Ideally I'd do a triangle test, but I'm not sure I can get her to play along with that after a full day at work!). No noticeable temperature change, or exciting bubbling happened (which was almost disappointing). The plan is then to dump everything back into the boiler, add the H2O2 and let it sit for a few days. Then I'll repeat the run and pray to the distilling gods. I'll update this post with the results. Or I'll watch my boiler fly off into a near-earth orbit... either way I'll keep you posted.

[tommysb]

Interestingly, the standard practice for making Calvados is to leave the cider on the lees for up to 6 months. In hindsight I should have dumped some copper into the barrel with the nutrients to eliminate the sulphurous stuff early on. I'll do some reading up though.

There's a folklorical advice that the cider from last year's harvest is ready when the apple blossoms appear for the next one - so about 6 months sounds about right! What's actually probably going on, is that the fermentation is pretty much dormant over cold winter months, and then as the weather warms up, the yeast gets active again and convert that sharp malic acid.

I was just thinking out loud with the reductive stuff but I am pretty sure it wouldn't be the source of your problem bringing in sulphur notes. I came across this idea of lees, cider and sulphur i when I first tasted a friend's natural wine and my first thought was 'this has a lot in common with lees-aged cider'. When I mentioned that, he said that his wine in that case had had an extended ageing on the lees. So there is a slightly reductive lees-y quality that can be obtained, but it;s a GOOD thing, typically! I digress...

[Tedd squirrels]

Distill your spoiled distillate with the addition of refined, deodorized, frozen, tasteless and odorless vegetable oil. Create a film of oil over the surface of the distillate 0.5-1 cm and distill in simple distillation mode, you don’t even need to select the heads. You will be pleasantly surprised.
Using a similar method, I forced my colleague to correct his defective distillate. The cleaning was successful, the colleague is happy.
Video without translation. But the point is that the defective Rumbon (Rum + Corn) was saved by distillation with oil:
https://dzen.ru/video/watch/65bc8ece44aac560d29053a2

My gut feeling is that while that may be quite effective, it's going to strip out quite a lot of flavour (I'm guessing the oil acts a solvent for fat-soluble congeners). The apple flavour in apple brandies is subtle enough at the best of times!

Yes, some of the taste goes away, but it is the most coarse, bad and not tasty. Another part of the taste of the original is subtle and very aromatic remains. When mixed with animal fats, there is an additional fifth taste of deliciousness (umami). When distilled with refined sunflower oil, the finest shades of creamy baked goods are observed. Thus, this method claims to be called gastronomic (culinary) aromatic distillates. This purification of vodka is of a different type; it is not as radical as rectification.

[NormandieStill]

So... I survived!

I dumped everything back into the boiler which was still full of the backset from that run, and added 250ml of 3% H2O2. This then sat untouched for just under 2 weeks. I then ran the whole lot again, as if nothing had happened. I had already ditched the fores from the first run, but I took a fores cut anyway, and then started collecting slowly (possibly a smidge faster than on the first run). Ran it out to 3 or 4 cloudy jars which took me down to <40% off the spout and clearly into tails, and stopped. This evening I put together a test blend.

So first and foremost. The onion smell has gone. As has the harsh burn that I was getting throughout the run. I was quite surprised by how far towards the start of the run I got before the heads got too obviously chemical. I do feel that the apple flavour has been a little muted, but that could easily have been a result of the wild yeast and their sulphur farting party! Anyway, I've got what seems to be a good blend which I'll test again tomorrow night before committing it to glass and oak!

So two lessons learnt.

1) Wild yeast are fickle. Next year I might experiment with the Torulaspora delbrueckii yeast that was mentioned in the Might be of interest to the Wine and Brandy guys thread. White Labs sell a version of it targeting cider production which claims to push the esters and bring out the apple flavour. I'll then follow up with a champagne yeast to eat all the sugars and out-compete any wild yeasts that are hanging around.
2) If you do bugger it up and end up with some noxious sulphurous compounds that copper doesn't take care of, a 2€ bottle of H2O2 from the pharmacy will clean it up nicely... I didn't even need to add any chicken broth!

[MooseMan]

So... I survived!
I didn't even need to add any chicken broth!

Hahahaha!!!

That comment not lost on me there Norm!

[Bradster68]

. I didn't even need to add any chicken broth!

Hmmm that's a whole other story

[bilgriss]

I had a really similar experience a couple of years ago with my cider. I too decided to ferment with the natural yeasts. The fresh cider itself was a pleasure, nice balance of sweet and acid, flavorful. When it was done fermenting, it was chemical, band-aid, funk - and none in a good way. I took careful cuts and ended up with a minimal amount for aging of the best. My hope is after some significant time aging on wood it will turn into something interesting. I haven't even sampled or smelled it since then. Just tucked it into a corner in the basement.

Last year I had an awesome pile of apples, but because my knee was damaged, I was unable to do anything with them. I'm thinking the next round I will probably use campden tablets and a wine yeast, and forego the risk of natural yeasts.

Sorry to hijack your thread, but this feels really familiar!