What the hell did I make? (troubleshooting)

[Uncle B]

Greetings all:

Apologies for a long post, but I’m hoping a few of you can help me troubleshoot what should have been a simple sugar wash...

Up to this point, I’d made several successful batches of a simple sugar wash – generally, 2lbs sugar to 1 gallon water (then diluted a bit to an SG of around 1.070), pH adjusted to the 5.0-6.0 range, using a “vodka yeast” (turbo-esque, low-congener, nutrients included in the yeast), and fermented at around 72° F. The end product (admittedly distilling more than once in a 5-plate flute), was actually very clean and drinkable.

This time, however, I tried a few things different:
• For the hell of it, I tried inverting my sugar a bit, by adding sugar to near boiling water with a pH of 5.0 (I used citric acid to lower the pH).
• I went with a lower gravity, this time about 1.060.
• Instead of the expensive vodka yeast, I used RedStar DADY.
• Added Fermax Yeast Nutrient, on the low end of the recommended pitch amount range.

The only other derivation was during the creation of my wash I overshot my pH range a bit, and adjusted upward with calcium carbonate. After adjusting, the two fermenters had pHs of 5.3 and 5.8. (Figured a range would give me some insight when looking at the result.)

Now, almost immediately the fermentation took off – and it smelled horrible, like nothing I'd seen before. Sulphury, but with something else I couldn’t put my finger on. This forced me to move the fermenters to my basement, where the temperature was pretty low (~68° F), especially for a DADY. I compensated by periodically running a space heater on the fermenters, and other than one point where the temp spiked to about 90° F, it generally stayed in the low 80s.

Two weeks later, I distilled both batches and noticed an odd but subtle smell from the distillate, almost like tails throughout. (Again, using a 5-plate flute.) I also noticed that the bottom two copper plates turned black during both distilling runs. (I chalked this up to heavy sulfur content.) I jarred my batches and allowed to air out for several days. When a long work trip popped up, I tightened the lids on my jars and let them sit.

Two months later, I open my lids and discovered the two jars with foreshots had completely eaten through the coating on the underside of the lid, leaving a blistered surface with orange streaks and blackened metal underneath. (Note, I’ve left a distillation sit in these jars before, and never saw anything like this. I also made a batch of rum around this time, left the foreshots in the jars, with no corrosion.) All other lids after those two 8-oz fores looked perfectly fine.

So while I was slightly concerned about the scents I was noticing, I’m now a bit alarmed that I created something in my foreshots that would eat through a plastic just by vapor alone. I realize this can happen if they're left to sit, but the combination of the terrible smells and lid corrosion (when I've never had the issue before) have me really wondering what I did.

Any thoughts or observations?

Thanks!!

Uncle B

[Yummyrum]

I’m now a bit alarmed that I created something in my foreshots that would eat through a plastic just by vapor alone.

This is why we have a rule about not using plastics or synthetics in a still or for storing alcohol in .

[Uncle B]

Yep. Already picked up some PTFE lid liners... lesson learned.

But that's not really addressing the question. Let's ignore the lid corrosion, what would cause such a drastic change in fermentation scent, even in the distillate?

[NZChris]

You did so many things different that I doubt you'll find out. If you really want to know, you might have to repeat your original recipe, changing one thing at a time. I suggest you start with the yeast.

[Boozewaves]

. i'm no means as experienced as many on here but this is what I have gathered based on my past m̶i̶s̶t̶a̶k̶e̶s̶ learning experiences

I have had smelly ferments that turned out fine after stripping and then a spirit or reflux run depending on what i'm making . the smell usually goes away after a few days .

red star dady is what I use , seems good but quite sensitive to inconsistent or wrong temperatures , well worth a bit of trial and error to keep the ferment at 28c or it can be a slow ferment or not start at all . my last dady yeast was less fussy but the ebay store I got it from has stopped selling it . making a good yeast starter is best rather than just sprinkling . I use a water bath to heat the fermenter from the bottom . keeping the yeast happy makes the best booze

a tried and true recipe is best especially if you are starting . this keeps the yeast happy too

never ran a flute but I know running a reflux still wrong can smear tails through the run

acetone which is in the fores/heads dissolves some plastics , I know this from spray painting when my gloves melted . acetone is a thinner for cellulose paint

[Uncle B]

You did so many things different that I doubt you'll find out. If you really want to know, you might have to repeat your original recipe, changing one thing at a time. I suggest you start with the yeast.

I was hoping someone had already come across this issue (or saw a glaring mistake), but you're right... I have some 1-gallon carboys; might be best to scale down and isolate the issue.

[Uncle B]

red star dady is what I use , seems good but quite sensitive to inconsistent or wrong temperatures , well worth a bit of trial and error to keep the ferment at 28c or it can be a slow ferment or not start at all .

Thanks for this. I suspect it's one (or both) of two culprits: either inverting sugars with a yeast that doesn't react well to that glucose/fructose form of sugar, or excessive temperature fluctuation.

On the later issue, since this batch i invested in some Inkbird temp controllers and aquarium heaters that have kept my current batch of rum at a steady 80°F, so at least going forward that won't be an issue.

But as Chris pointed out, a trial isolating factors might be in order....

[The Baker]

this is what I have gathered based on my past m̶i̶s̶t̶a̶k̶e̶s̶ learning experiences

Love that.

Geoff

[The Baker]

I use Birdwatchers sugar wash recipe from the Tried and True recipes.

Bakers yeast only, not anything like Turbo.
(I used to run a bakery so that's obvious anyway.)
Though I have used the dregs from my brother-in-law's home brew beer and that worked fine too and was free too.

I always invert all the sugar, with lemon juice.
Simple to do, saves trying to mix the sugar into the wash.
Put some cold water into the fermenter first, then add the hot invert sugar, don't have to heat water for the wash.

I never stuff about, checking and adjusting pH, it's fine if I follow the recipe;
some shells in a cotton mesh bag take care of any problems anyway.

Keep the wash warm with an aquarium heater.

Don't overthink it, follow the tried and true recipe.

Geoff

[shadylane]

Added Fermax Yeast Nutrient, on the low end of the recommended pitch amount range

Try adding some boiled yeast and recommended amount of Fermax.
The wash smelled sulfury because the yeast didn't have enough nutrients.

[subbrew]

the sulfury smell could be from fermenting too cold for the yeast. Although if you heat it up to the proper temperature at the end of the ferment the yeast will usually clean that up. It is a common issue in Lager beers which are fermented cold (55 F.). Other stressors such as lack of nutrients as Shady pointed out will also cause yeast to produce sulfur compounds. So the solution is keep your yeast happy with nutrients, temp and a lot of O2 at the start.

[Uncle B]

Thanks all. I'll play around with it, and see if I can pinpoint the issue. Hopefully it is just a fermentation temperature issue.