How long safe to run still on old mash?

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TommyinaJar
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How long safe to run still on old mash?

Post by TommyinaJar »

Hi long explanation, short story= I mad two 12 gallons or so mashes, a simple sugar and a molassis, brown sugar rum mash. I got called away. How long is it "safe" to run it still. I know it's been asked but not about both. Also would like a 2021 answer. Thanks!!?!
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Re: How long safe to run still on old mash?

Post by NormandieStill »

You made two *washes* not mashes, there were no grains involved!

Assuming that you are asking how long you can leave them before running them, it is "safe" to run it for as long as you want. Ideally you want to keep the fermenters closed with an airlock to prevent beasties from entering. If you leave them alone they should maintain a decent cover of CO2 which will prevent infections. If you've futzed with them, racked them off into new containers, stirred them lots, taken some out to drink, you may lose the CO2 and so you run the risk of an infection. That risk increases in proportion to how unsanitary your setup was in the first place. If you didn't clean anything and were relying on a rapid progress from fermenter to still then you might have problems. In short... only you can answer this question. But use your senses. When you come to run the wash have a look, smell, taste. And then if that raises any red flags, search the forum to find out what you might be dealing with.

If you've already searched the forum you may note how strangely similar this answer is to previous ones. That being because despite it being 2021, microbiology hasn't really changed a great deal in the last few hundred years! :wink:
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jonnys_spirit
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Re: How long safe to run still on old mash?

Post by jonnys_spirit »

I just ran some wines that I had bulk aging for about 18 months... Turned out great! I guess it probably depends on how long it was stored, pH, ABV, exposure to O2, and perhaps exposure to acetobacter or other bacterial infections that may have depleted ETOH or otherwise spoiled it..

Run it for a strip!

Cheers,
j
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i prefer my mash shaken, not stirred
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zed255
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Re: How long safe to run still on old mash?

Post by zed255 »

A finished mash, wash, must, beer, cider or wine if left sealed up and was prepared in a reasonably sanitary manner can sit potentially for years prior to running, especially off the lees / trub. I've left things sit several months in the past and in my case the product actually improved. If you strip the ferment into low wines then its shelf life becomes indefinite (read as a loooog time), low wines have sat over a year to no ill effect and perhaps have improved the end result.

The only real limits are infection, oxidation and maybe becoming light struck, likely in that order.
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Jstroke
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Re: How long safe to run still on old mash?

Post by Jstroke »

I guess I'll answer it a slightly different way. "Safe" is the question you asked. That is either related to the question of making you sick.

Bacteria has a hard time living in the environment of a hot still and consequently surviving the vapor path.

Run it, you never know what might come out. You might make something you spend a lifetime trying to duplicate. On the other hand you might make something nasty and in which case you learned something. It's a win either way.
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Re: How long safe to run still on old mash?

Post by Hambone »

If you kept the vinegar flies out you’re fine…
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Experience is usually the result of bad judgement..
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Re: How long safe to run still on old mash?

Post by still_stirrin »

Bacteria can and will consume alcohol even after the yeast has stopped producing it. And bacteria will survive in temperatures beyond what yeast can tolerate. But, bacteria will not thrive in an acidic environment. So, just as your yeast will produce acids during the reduction of sugars in your wash, the lower pH will retard bacterial infections. It is unlikely, therefore that a bacterial infection will ruin your sugar wash during a long post-fermentation pause unless you raise the pH too high, ie - addition of a strong base or possibly a long exposure of calcium carbonate after the yeast has attenuated.

Typically, a fermenter if not exposed to air or contaminated (by dirty fingers) will wait a long time (ask Cranky … a year or more) for you to distill it without going bad. But keep in mind the “conditions” I outlined above.
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Re: How long safe to run still on old mash?

Post by Yummyrum »

I just ran 100 liters of Rum wash I put down in February . It was just fine .
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Re: How long safe to run still on old mash?

Post by DieBoer »

I had a similar question and stumbled upon this thread. I ran a sugar wash in January this year. The wash was slow and stopped 4 weeks later. The Last gravity reading showed it still had about 20% to go. Tried a few 'tricks' to get it going again, but eventually just gave up on it. About 2 weeks later, one of the fermenters had some movement, but it was only for a few days, and then stopped again. Was a bit upset about it, and just ignored it...until today, 4 months later.

The missus gave me some flack..." when are you cleaning up your mess" - guess many of you know the drill. So I opened them up today planning to just dump it, but what I found inside was intriguing. A clear wash, with a nice 'wine-like' smell. Gravity reading nicely under .998. Couldn't resist, so gave it a taste, and it tastes pretty good. So I racked it. Left a good 5l at the bottom to wash away with the yeast cake. It's neat and clear. I think I may just go through with it and run it. No harm in it right?

Probably run a usual fast strip run, and then do a few really slow ones. (I have a good old copper pot still) Need to get as much of a clean neutral spirit out of this one as I can get, given the limitations of a pot still.
TommyinaJar
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Re: How long safe to run still on old mash?

Post by TommyinaJar »

Hey thanks, guys very useful.

It's pretty overwhelming, the booze smell. I feel buzzed every time I'm in the room. I'm running it FINALLY this weekend. I can use it as cleaner if it's shit- I kinda figured it'd be ok if I don't pass out doing it. :)
If more family "emergencies" don't occur. (sister-in-law getting evicted w 3 kids, in another state...)


oh brother......
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jonnys_spirit
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Re: How long safe to run still on old mash?

Post by jonnys_spirit »

I saw someone mention adding a slight bit of sugar (or other fermentable) every week or three to keep the CO2 in the headspace without significantly increasing ABV - I thought that was a pretty good idea - In case this ever happens again and there is concern..

Cheers!
-j
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i prefer my mash shaken, not stirred
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