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Bacterial Infection affecting odd medicinal Taste

So I had been having issues with off flavors in my neutral. I've been experimenting with different recipes but the taste would always creep back in.

what we tried:

  • reducing pitching temps. I was pitching the wash at 104F to suspend the temps and give the yeast a good enviro to start per directions on packages. Forget this crap for me. my water is 82F out of the ground and it suspends the raw sugar nicely. further a large dose of instant bread yeast (100g/5-6gal mash) does the trick nicely. Reducing the temps seemed to help quite a bit but the flavor would still come back

  • different recipies. tried beans, cucumber, boiled yeast nutrient, Turbo yeast at full and partial strength, but the flavoralsway came back.

  • cleaned out still really really good. this helped some but flavor came back again last batch.

what worked:

  • after discussing this with a chemist lab guy with years of experience, he says" you know that sounds like a bacterial infection"

I'm like "dude, we are pulling off 92% alcohol here it should kill everything right?"

He's like "there are some pretty extreme bacteria out there and you may have bred one or something!"

So, I decided to just bleach and re-clean everything. all bottles, fermenters, lids, still, tools everything. then sterilized lids and bottles really good (recycling wine bottles for now).

well, as of right now, I'm pulling off the cleanest neutral i've ever gotten with NO hint of the medicinal smell!

Last run we were all sterilized really good as well, but the stripped product was contaminated apparently, so when we ran it, the infection came over again (not as bad mind you) and gradually changed to the medicinal smell again. weird that it could survive the still and alcohol huh?

I was going crazy trying to figure this out. filtering water, using spring water, changing yeast and recipies etc. Not sure where this started,but I think it started with the turbo and high pitching/fermenting temps.. Something must have been just right and I created a monster. I'm still trying to eliminate any possibility of return, but maybe this will be a cautionary tale for those of us in remote tropical areas.

Wish I could get potassium metabisulfite huh?



  • edited March 2014

    Infection, yep had one in a fermentation once, but it was easy to spot, wash stinks and the grain bed... 2 barrels exactly the same, roughly 4th or 5th gen





    2nd barrel was normal


    It was also in summer peak, hot weather, but I know I opened the lid during fermentation, my fault. Tossed the lot, wash, sanitize, air dry in sun, sanitize, then made another batch using 1/2 the good barrel.

    I'm glad you seem to have nailed your issue, its rewarding to produce a nice drop that can be enjoyed whatever you choose to make out of it. Reckon you have had a trying time so far by your posts.


    800 x 600 - 41K
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  • Yeah didnt have any obvious signs like that. smelled OK coming off still, but then once in the bottle and cut to strength it would develop from 1-14 days later. got progressively worse.

    Sneaky little buggers these are!

    I'm still paranoid it might be in there actually. we'll see in a few days if it comes back.

  • Are you saying that you think that there is a bateria that is carried over from the wash to the spirit through the distilling process, is growing in the bottles at 40% ABV and producing some nasty tasting compounds over time?

    I do not like to say impossible but I would say this is extremely unlikely to be the correct explanation to what you are observing. It would seem more likely that, if this originates from baterial contaminaton, that it would be bacteria in your wash creating compounds that are carried over in the distillate and, through ageing-oxidation, generates some nasty tasting things. Are you certain that your bottles and caps are not degrading in the presence of spitits?

  • If any bacterial infection has happened during fermentation, it is hopeless to get rid of the smell or taste in the product later on. This is, what we learned in our distillers school. It is not the case, that the bacteria are still in the booze, its just the smell. If you want to sanitase, please do never use chlorene, only citric acid. Again, this is, what our teachers told us. I hope, you can use this information!

    StillDragon Europe - Your StillDragon® Distributor for Europe & the surrounding area

  • I'm with Ben, 70% abv ethanol is one of the best sanitisers in the world and is good enough for microbiological work (of course flame works better B-) ). It could be any number of compounds from those that are produced during fermentation to those that are produced via distillation. Unlikely to be a living agent.

    I'd be looking at that bakers yeast myself.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • The medicinal taste (at least in beer) is generally caused by eiher i) presence of chlorine in the wash from improperly rinced bleach used for sanitation or from city water that has high chlorine levels. Fermentation in presence of chlorine produce chlorophenols that have a strong medicinal taste. ii) some bacterial contamination can produce medicinal tastes as well.

    The chlorine levels in the city water can vary during the year yeilding an alternating problem if it is the source.

  • I agree with Ben, chlorophenals are detectable in the ppb level. Chlorine is highly reactive with organic compounds and will generate chlorophenals almost instantly. Once made they are very stable. I would suggest never using bleach and using a good sanitizer like starsan instead. It's also good to filter all your water through carbon. Finally, if it is an infection, probably time to replace all your non metal items that come in contact with your beer/wash...hoses, fermenters, hose line and clean and sanitize everything else, breaking down fittings and valves to get into all the nooks.

  • why would it get better after sanitizing with bleach, steam and heat? (and rinsing like crazy after bleaching)

    same vessels, same yeast, same sugar, same still (but cleaned), . Lower brew temps have helped for sure.

    for the record, I dont have access to sanitizers typical of a brewery or distillery. I have to make what I need from raw materials or locally available things. I have lots of sunlight and heat and rainwater available in any event.

  • what are you rinsing with?

  • spring water usually. just lots of water.

    It's possible the water might be the culprit. we filtered it in the wash this time too. but I did cut the spirit run with unfiltered water this time and it seems fine.

  • edited March 2014

    In any case, I too would be using 70% abv ethanol over bleach. Bleach may not be working as well as you think sometimes. It has a shelf life and has a really short shelf life when mixed with water. And it is corrosive

  • what about levels of iron in the water?

    that is the other thing we did different this last batch was to filter the water in the wash for fermentation.

    pain in the ass filtering 25 gallons of water thru a backpackers filter tho!

  • I use a KD85 iron filter works great and flow rate is very fast.

  • OK, so an update on this and what we think is the problem. Its back!!

    Started filtering the water and did a bottled water VS filtered water comparo (filter is an absolute .1 micron sawyer water filter so it's free from bacteria). slight advantage to bottled water but it didnt eliminate the smell.

    did our cleaning with mild bleach and copious water to rinse after. cleaned still well. all this seemed to help but did not eliminate the smell. I still have not been able to obtain any sanitizer to play with.

    Gave it to a 30 year master brewer here in Fiji last night. he commented that he thought it was cleaner than the neutral he was producing, but that it did have a mild smell of butyric acid. I'm not sure I agree but it is mild and he knows a hell of a lot more than I do, so I'll proceed based on that evaluation.

    This smell have been consistent with all our ferments, but was less pronounced with the bottled water.

    So QUESTION: what causes butyric acid production and how can I deal with this?

    From what I can gather I still think it's a bacterial or microbial infection (maybe from the air) creating this somehow. We pulled off this wonderful world class vodka with the bottled water ferment/distillation then a week later the smell starts back in. this from sterilized bottles and caps and cut with bottled water.

  • If it is butyric acid you'd be looking at a bacterial infection such as clostridium. What is your process? Are you boiling your wash or just mixing your ingredients and hoping the yeast take over? If the latter perhaps try boiling first and then pitching clean yeast. If using plastic fermenters you may consider replacing them

  • Currently my process is to clean fermenter with soap and sanitize it lightly with bleach then rinse well with water to get bleach out. then filtered water is added and sugar, nutrient are added and mixed into suspension (at 82F) yeast is then added and vigorously stirred in. top with airlock is affixed and left til done. a stripping run is performed, then spirit is cut with filtered water and redistilled again. product is placed in heat sterilized bottles and caps and stored till use.

    I am not boiling right now. I used to heat it up (not to boiling) and then pitch at 102F but that was worse than what I'm doing now.

    I am using plastic. is that bad? I dont have much option here really so understanding the whys of a problem can help me solve them in other ways.

  • edited April 2014

    Couple of issues.

    If you are using plastics to ferment - bacterial infections are a challenge, once you get scratches in the plastic, they harbor the bacteria. If all you have is bleach, fill them with water and bleach and let them SIT, and SCRUB.

    You need better sanitizers, and depending on the sterility of your source water, you might opt to go with a no-rinse sanitizer, since rinsing can re-introduce bacteria.

    .1 micron filtration is only moderately effective at eliminating bacteria, depending on your source water. You'd likely need to move up to UF .01 micron, or add UV treatment to your source water.

    Boil, boil - it's some toil but you'll save yourself the trouble. Bringing it up to 102F will make it a great place for bacteria if you don't boil.

    Really think given your constraints, boiling in the same vessel that you will ferment in is the simplest way to eliminate potential infection concerns, since after a 15-20m of boil, both the container and wash should be realistically sterile. Whether or not you can do it, another matter. At that point, the only other concern is clean yeast.

  • edited April 2014

    You should give the above a good try. As a minimum I think you should ditch the bleach and rinse method and spray 70% ethanol in your fermenter and Don't rinse.

    Some bacteria will survive a boil as well, for a while anyway. A split second of open unfiltered air can introduce a dozen or more types of infection. Anyone who has ever grown mushrooms will attest to this. The only true way to sterilise, is to get temps up to 120C for some time. Think auto claves and pressure cookers. I know this is not much help when it comes to distilling but its a good way of understanding how persistant and hard to kill some bacteria and mold can be. Knowing how the mushroom growers and also canners deal with and treat infections may help,

  • From what I can gather the nasties are not attacking the finished product but are, instead, a part of them from the ferment. (As strange as that sounds that it carries over in the distillation process).
    Can you try "over-proofing" your product to, say, 45% ABV to see if it stops the nasties?

    That does not resolve the root of the problem which is obviously the ferment. I have never, not once, had this particular problem so I'm wont to offer advice and, more than anything, trying to understand the problem. From what I can glean from the great and powerful internet, everything points to the ferment so we should start there.
    I know you can't get starsan type cleaners there easily but the many members here should be able to help. I know I can ship a kilo or two of it to you (a little goes a long way) but I'd need to source it from Shanghai to send to you. Maybe some other member could supply it cheaper to you?
    Guys... chime in here if you can help.

  • edited April 2014

    I could ship starsan to fiji if Fiji_Spirits ships me back some of fijis finest kava:)

  • Grim really drives at the gist of what I was trying to figure out. If you are not running a sterile ferment via something like boiling and also using plastic fermenters you are running the risk of infection. Further, using bleach as a sanitizer keeps the potential of your issue being chlorophenals. It would really help to sanitize with something other than bleach to eliminate that variable from the equation.

    Take this from what it's worth as I have no practical experience with distilling, just a very experienced and educated home brewer that has read up on some distilling for enjoyment sake. What if you had a bacterial infection in the ferment and the compounds from that infection that are causing the off flavor also happen to ride along through distillation? Perhaps they seem to intensify as the spirit ages as the spirit off gasses components that cover them up initially? Or perhaps chlorophenals are riding through the distillation? Either way, from what you have said I'm guessing the issue is in the ferment side of things and that is carrying through to the end product.

  • This is the only possibility as nothing will live in the alcohol.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • Unless it's phenols coming from the water being used, then it could be a chemical reaction occurring at any point. Agreed that it couldn't be biological post distillation.

  • I really think the possibility of this being bleach centered is minimal. we didnt even use bleach until after this had become an issue.

    My feeling is that the plastic ferment buckets may be harboring bacteria and creating butyric acid at that level. it then comes over in the distillations. this would seem to answer the questions: -why it survives distillation twice and high alcohol levels -why it persists in spite of sanitizing with low levels of bleach (staying in the scratches) -why it got better after bleach (sanitizing killed off lots of the problem but not all)

    what I'm not sure of is" -why it gets worse as it ages in the bottle?

    lemme keep trying on the main island for a source of a sanitizer. it has to be here somewhere.

  • Look for a restaurant supplier first, janitorial supplier second - or if you can't find either, head straight to the biggest and best drinking establishment you can find. I would be surprised if you couldn't find a Quaternary Ammonium type product (Steramine) - which is common if bartenders are washing glasses behind the bar in a typical 3 sink setup - soap - rinse - sterilize). Careful with this stuff though, get the test strips and study the instructions, it is less forgiving than something like Starsan.

  • @Fiji_Spirits said: -why it gets worse as it ages in the bottle?

    Some ideas on this:

    • The concentration of the nasty tasting stuff is not changing but as your product ages and smoothes out you can perceive it better, giving you the impression that it increases over time

    • What the bacteria produces is a precursor for the nasty tasting stuff which is produced slowly by aging type reactions in your product (oxidation, etc..).

  • Perhaps time to scrounge up some stainless drums for your fermenters or adjustable wine fermenters also work great for fermenting quantity on a budget.

  • Ferment with drum liners in place and throw them everytime if your worried...

  • edited April 2014

    @FullySilenced said: Ferment with drum liners in place and throw them everytime if your worried...

    That's a damn good idea. If you can unscented bin liners the right size you may have the solution right there.

    No sanitizing required, they'd be near enough to sterile straight off the roll.

    StillDragon Australia & New Zealand - Your StillDragon® Distributor for Australia & New Zealand

  • I have heavy 55 gallon drum liners think they are 8 mil think.. some heavier some lighter depending on the need but plenty different styles on the market...

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