Sudzie

Rum fermentation got strange

11 posts in this topic

Everything was going normal as in the past two years of making rum and then BAM!  Two days ago I noticed a couple of small dime size spots and today there is a full blown something going on???  Any ideas?

Ty

Dave

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You've got yourself a nice infection going there, maybe lacto?

Probably something in your process was less than sanitary, your ferment was taking too long, pH too high, or all of the above?  I'd run it and see how it turns out, but I'd be absolutely sure to give everything a proper clean/sanitize before starting the next batch.

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Hi Sudzie,

Yes, looks like a lacto infection. Open top fermentation? Sanitation procedures? Feedstok molasses that didn't get cleaned? Running malted barley in your distillery? Just asking, because these are common sources of lactobacterial infections. Another one is adding dunder to the ferment.

Regards, Odin. 

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It's very difficult to identify the specific bacterial strain from a pellicle photo, it could be a half dozen different bacteria.

Can you describe the smell?  Is it more acetic than usual?  Do you smell any rancid, butter, body odor, or vomit?  Any slime or ropiness if you stir closely below the surface?  Just keep an eye on it and see if it begins to appear to be a mold, in which case remove it.

I intentionally pitch specific strains of non-yeast bacteria in my rum fermentations to encourage specific ester formation, and I'm starting to work on mixed culture whiskey fermentations, with very good results.  There are a handful of lactobacillus strains that I absolutely adore in whiskey and rum.  Yes, I said that, and yes I intentionally "infect" fermentations.

Every whiskey fermentation that doesn't boil after mashing is "infected" with numerous strains of bacteria.  Grain is incredibly filthy from a microbiological perspective.  Even some strains of Streptococcus can survive lower-temperature cereal mashes.  Same for the rum distilleries, just a different set of bugs.  In addition, you'll develop your own mix of strains that define your house/colonial bacteria profile.  What I do is force a specific profile to match the outcome I am looking for.

Let it ferment out, run it, it may be the most interesting rum you've made.

Here are two of my favorite papers on the prevalence of specific bacterial strains in whiskey distilleries:  

http://www.microbiologyresearch.org/docserver/fulltext/micro/147/4/1471007a.pdf?expires=1483011394&id=id&accname=guest&checksum=3F2159A77F8BCEB870E570C224754586

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC126549/

And Rum:

http://onlinelibrary.wiley.com/store/10.1046/j.1365-2672.1998.00380.x/asset/j.1365-2672.1998.00380.x.pdf?v=1&t=ixabpopp&s=5841ec634998983c0b050add5b2dbeba52bd555c

 

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Odin,

Open top fermentation?  Yes we do..

Sanitation procedures?  Hot water rinse (185*), mist and wait of brew-z to dissolve residue, Birk-Ox (peracetic acid)

Feedstok molasses that didn't get cleaned? Same lot as 3 batched prior with no issues

Running malted barley in your distillery? Yes, for our bourbon

Just asking, because these are common sources of lactobacterial infections.

Another one is adding dunder to the ferment. Been using Dunder with our fermentation for the past 2 years never an issue but results are awsome.  Rich, buttery, dry rum and it ages out fantastic. 

 

Silk

Can you describe the smell?  Molasses, normal

Is it more acetic than usual?  Finishing out at normal 3.2ish

Do you smell any rancid, butter, body odor, or vomit?  None

Any slime or ropiness if you stir closely below the surface?  No, 

Just keep an eye on it and see if it begins to appear to be a mold, in which case remove it.  Will do, I'm running it on Saturday and will post.  

 

And thank you you all for your replys on this.  I'm going to take a lot of more pictures of it along with a good sized sample.

Dave

 

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Yeah definitely sterilize a few containers and keep samples, if the result is great you are going to kick yourself for not attempting to culture it.

I think there are lots of clues on the specific bacteria in the late heads.  Typical acetic strains will just result in a larger than usual heads cut, nothing particularly interesting.

But strains that generate higher amounts of butyric and propionic acid esters are where it's at - you'll get these in the late heads.  

Propionic and butyric esters - tropical fruit, bubble gum, rummy, pineapple, strawberry, apple, etc. 

Low acetic lacto strains are harder to pick out, slightly pineapple in the late heads, but without the juicy-fruit gum, slightly buttery early tails - but broadly contribute to the buttery/rich descriptor, absolutely - creamy, caramel, buttery, nutty.

 

 

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Brett is easy to pick out - phenolic and band-aids.  Almost tastes/smells like you are running a peated malt wash.  Absolutely ruins rum, IMHO.  Significantly more obvious on grain than sugar.  Also known as Dekkera in the rum literature.

 

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1 hour ago, Silk City Distillers said:

Brett is easy to pick out - phenolic and band-aids.  Almost tastes/smells like you are running a peated malt wash.  Absolutely ruins rum, IMHO.  Significantly more obvious on grain than sugar.  Also known as Dekkera in the rum literature.

 

I can vouch for that statement. Early on we had a small batch which got a slight infection and the end result was rum that had a gross plastic/band-aid odor.  Now that all our vessels are stainless and have CIP it hasn't occured again *knocks on wood*.

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... if you mill your malt on location, bacteria easily lift with the dust that's formed into open fermenting. Not saying that's the cause, but it is something you might want to look into.

Regards, Odin.

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On 12/29/2016 at 6:43 AM, Silk City Distillers said:

But strains that generate higher amounts of butyric and propionic acid esters are where it's at - you'll get these in the late heads.  

Propionic and butyric esters - tropical fruit, bubble gum, rummy, pineapple, strawberry, apple, etc.

Trick with butyric and propionic is a little goes a LONG ways. The lingering stench of vomit and BO is tough to get out of the distillery (and a real tasting room clearer).

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Agree.  Funny story.  I've got a little lab setup with a number of different alcohols, esters, aldehydes, and other chemicals, and often times run two-component distillations to understand the esterification that takes place during distillation (Fischer esterification takes place in spades during refluxed distillation, even with no inorganic acids present).  So anyway, I spilled a tiny bit of butyric acid on my pants, no more than a few drops.  It smelled awful, but after an hour or two, I didn't notice it anymore.  When I got home, I just threw the pants in the wash.

The laundry room smelled like vomit for a month.  My wife was not impressed.

Interesting anecdote about butyric acid - if you've ever watched the show Whale Wars - it's what the anti-whaling protesters throw onto the decks of foreign whaling ships.  I can't imagine how awful an entire glass vial of that, smashed onto a deck, would smell.

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