Rum wash infection management

[JustinNZ]

G’day. I make SBB’s in 45L fermenters at 33deg C. I normally distil twice but sometimes do a 1.5.

Anyway, I fermented on a 3-week old rum trub and got an infection of some kind. It produced a delicious, tangy ferment and for me that’s a desirable thing. And the flavour came through strongly in the low wines. I feel that once aged on oak for a year or two it will make for the tasty rum I’m after.

But, only 40% of the unusual alcohols were produced (6L at 33% abv instead of 15L) meaning it had stalled or the infection ate at least half the sugars, or a combination of both - or something else. Not a desirable thing. I didn’t take an FG, D’oh! I’m a sour finger run it guy - but that would have been useful info.

I kept 10L of the Dunder for future purposes - ferment or spirit run.

I started a new wash on top of the infected trub but without the usual Dunder because I was concerned the combo of Dunder and infection might have stalled the ferment (and it’s alive and well).

I also kept 1.5L of the infected trub in a jar in my fridge.

And… mixed 15L of the tasty Dunder with water and 3L of molasses and some yeast. Nothing happened there. Not a surprise - just got a bit stupid. So I removed 20L of the currently infected and active ferment (was at 1.045) for a big 1.5 I’m doing and replaced it with the dead Dunder-water-mix to see if I can get some life out of it.

It’s been fun. From your experience, what’s the best way to keep decent levels of alcohol production WITH the infection? My reading here suggests adding infected wash to an almost finished wash is a winner. Will mean having dedicated infected fermenters though and serious-arsed cleaning between ferments. Thoughts?

[tombombadil]

I had a similar experience a while back.

I threw some funky dunder in to a big fermentation.

Smelled strongly of vinegar after a few days, still sweet though, like a really funky sweet and sour sauce.

I started checking the ph, could not keep it up.

My suspicion is the acetobacter infection was producing vinegar as fast as the yeast was producing alcohol.

Everytime I added chalk or whatever to get the ph up, fermentation would temporarily resume and the ph would crash again.

I did eventually get it pretty dry and distill it. It turned out nasty. I dumped all but one quart, kept it as a reminder.

Now, after learning my lesson by wasting 10 gallons of black strap molly, I do a large clean ferment and a smaller dirty ferment.
I ferment them separately and distill them together.

If I remember correctly, in one of the cousins interviews, they mentioned adding muck at the end of the clean fermentation to get higher ester content.

They probably have a reason for doing that...

[JustinNZ]

Thanks for your thoughts. Fermenting separately in different proportions then distilling together makes a lot of sense. Cheers. I’ll just have a permanently sick fermenter, which is fine. Adding the muck late in the fermentation is also cool, but will require good cleaning to reset the fermenter for the first stage.

I’ll see what this lot tastes like tomorrow off the still. Got 28L of clean low wines, 6L of ‘tasty’ low wines, and the 20L of infected ferment to run.

I like my rum a lot, but I just want a little bit more flavour through the middle. I run a simple all copper pot still, by the way.

[SaltyStaves]

My reading here suggests adding infected wash to an almost finished wash is a winner. Will mean having dedicated infected fermenters though and serious-arsed cleaning between ferments. Thoughts?

As I see it, using infected wash/dunder in a live fermentation will eventually lead to a stall or total failure that can't be restarted. Infected wash with lots of unfermented sugar is a pain to deal with.
Also, I'd rather have dedicated muck pit/dunder storage that I don't have to sanitize.

I too have a pot still and my preferred protocol is to make a clean fermentation, strip to low wines and add those to infected dunder/muck/skimmings, actively aerate for at least 30mins, then strip again or spirit run (depending on whether I want a double distilled or a two and a half).

[JustinNZ]

I like that. Cheers. Perhaps I should use this infection to get a quality pit going. I’ve got a bit of a half-arsed one going at the moment - just 20L of Dunder given a bit of Parmesan and yoghurt sitting around with a loose lid out in the garden. Which I haven’t used. I think I’ll go bigger.

2.5 eh? Kudos. Rum and Coke time down here.

[SaltyStaves]

2.5 eh? Kudos. Rum and Coke time down here.

Well stripped twice before the spirit run.

Dark and Stormy for me.

[JustinNZ]

Well I did my 1.5-ish spirit run with 28L clean low wines, 6L of ‘infected’ low wines and 20L of infected fermented wash and it tasted… interesting. The late heads and safe hearts were great, but the late hearts early tails were where the tangy came through most noticeably, but it had changed from what I was tasting in the ferment to borderline hint of egg-fart. Now egg-fart isn’t on any rum label, but this was at the ok end of the spectrum. If that’s possible. More like an acidic fart a dog might do when visitors arrive. I’m not doing this well. It was subtle, mind you. I’m just thinking it will transition over time. Maybe.

Anyway, the change to full tails was vicious and I stopped there cos it was late.

Anyway, 10L is now aging on new and used (bourbon) us oak for a year.

Didn’t realise the infection was feeding on alcohol. That’s out of it. I need to read slower. Have a possibly very low abv 45L infected ferment to strip now with some feints today. Could be an expensive folly, but the Dunder should be nice at least. Hopefully. Gonna stick to adding Dunder and or muck to distillations in future - but keep my jar of infected wash just in case.

Thanks for your ideas. Any more most welcome.

[MooseMan]

Well I did my 1.5-ish spirit run with 28L clean low wines, 6L of ‘infected’ low wines and 20L of infected fermented wash and it tasted… interesting. The late heads and safe hearts were great, but the late hearts early tails were where the tangy came through most noticeably, but it had changed from what I was tasting in the ferment to borderline hint of egg-fart. Now egg-fart isn’t on any rum label, but this was at the ok end of the spectrum. If that’s possible. More like an acidic fart a dog might do when visitors arrive. I’m not doing this well. It was subtle, mind you. I’m just thinking it will transition over time. Maybe.

Anyway, the change to full tails was vicious and I stopped there cos it was late.

Anyway, 10L is now aging on new and used (bourbon) us oak for a year.

Didn’t realise the infection was feeding on alcohol. That’s out of it. I need to read slower. Have a possibly very low abv 45L infected ferment to strip now with some feints today. Could be an expensive folly, but the Dunder should be nice at least. Hopefully. Gonna stick to adding Dunder and or muck to distillations in future - but keep my jar of infected wash just in case.

Thanks for your ideas. Any more most welcome.

Thanks for detailing Justin.

All this is interesting stuff for me at the moment.
I'm on my 3rd Rum ferment and have the first 2 stripped and ready to run with the currently fermenting 3rd batch once it's done and settled out.

Not got any infected stuff yet but maybe I'll start a small pit...

[JustinNZ]

That’s cool, Mooseman.

I’ve never been a risk-taker and doing weird shit with rum requires a bit of risk-taking - or at least a leap of faith. I’m building up a nice little army of rums to one day blend. Bloody good fun this hobby.

[howie]

Well I did my 1.5-ish spirit run with 28L clean low wines, 6L of ‘infected’ low wines and 20L of infected fermented wash and it tasted… interesting. The late heads and safe hearts were great, but the late hearts early tails were where the tangy came through most noticeably, but it had changed from what I was tasting in the ferment to borderline hint of egg-fart. Now egg-fart isn’t on any rum label, but this was at the ok end of the spectrum. If that’s possible. More like an acidic fart a dog might do when visitors arrive. I’m not doing this well. It was subtle, mind you. I’m just thinking it will transition over time. Maybe.

Anyway, the change to full tails was vicious and I stopped there cos it was late.

Anyway, 10L is now aging on new and used (bourbon) us oak for a year.

Didn’t realise the infection was feeding on alcohol. That’s out of it. I need to read slower. Have a possibly very low abv 45L infected ferment to strip now with some feints today. Could be an expensive folly, but the Dunder should be nice at least. Hopefully. Gonna stick to adding Dunder and or muck to distillations in future - but keep my jar of infected wash just in case.

Thanks for your ideas. Any more most welcome.

i didn't think the bacteria can feed on alcohol, more likely feeding on sugar, in competition with the yeast.
i don't know at what stage your 'vicious tails' started, but they might have been the rum oils, which should be kept for the next run.
a good read is Pugirums thoughts and methods on rum oils, which are also mentioned in some old rum studies.
rum oils are very 'stinky', but if added to the next spirit run, add a certain taste to the hearts.
i use dunder and muck in distillation, but only dunder in fermentation (so far)

[NZChris]

i didn't think the bacteria can feed on alcohol, more likely feeding on sugar, in competition with the yeast.

Look up acetobacter.