backset fermenting

[zharleydave]

Ok I kept a gallon of backset to use in my next run but i didnt seal it up just put a paper towel in the gallon jug now its fermenting like crazy im guessing its making vinegar and should not be used ??

[still_stirrin]

I’ve seen backset get a moldy layer.

But I have not seen it ferment. Usually the backset is very acidic, sour enough to kill yeast and keep it from fermenting. Also, I would have thought that your wash would have fermented out any of the sugars before your distilled it. So, I am surprised backset would, or could ferment.

You’re not mistaking trub for backset, are you? Trub is what is left behind in the fermenter when you rack off the beer into the boiler. Backset is the liquid left behind in the boiler after distillation. Yeast would definitely be sterilized in the boiler during distillation.
ss

[Demy]

It is very strange that it ferments "like crazy" ..... the fermentation yeast ( in the boiler) will surely be dead so let's rule it out anyway. Did you add any ingredients? Perhaps as still stirrin says you confuse the fermenter yeast bottom? I'm just trying to understand ...

[Bushman]

My thoughts are with still_stirrin:

Backset The liquid left in the still after distillation has completed. Essentially a weak, acidic beer which has been boiled for a number of hours. Used in the creation of sour mash whiskey.

Trub Term used for the lees, or layer of sediment, left at the bottom of the fermenter after the yeast has completed the bulk of the fermentation.

[NZChris]

What is the SG?

[zharleydave]

I’ve seen backset get a moldy layer.

But I have not seen it ferment. Usually the backset is very acidic, sour enough to kill yeast and keep it from fermenting. Also, I would have thought that your wash would have fermented out any of the sugars before your distilled it. So, I am surprised backset would, or could ferment.

You’re not mistaking trub for backset, are you? Trub is what is left behind in the fermenter when you rack off the beer into the boiler. Backset is the liquid left behind in the boiler after distillation. Yeast would definitely be sterilized in the boiler during distillation.
ss

Its technically dunder i guess from a sweet feed mash but it had finished out close to 1 so there was little sugar in it maybe the unconverted sugars are being converted by something other than yeast! Im not sure how to post a vid or i could show you .
Thanks for the reply Zharleydave

[zharleydave]

It is very strange that it ferments "like crazy" ..... the fermentation yeast ( in the boiler) will surely be dead so let's rule it out anyway. Did you add any ingredients? Perhaps as still stirrin says you confuse the fermenter yeast bottom? I'm just trying to understand ...

No i saved a gallon of dunder/backset to put in with my next fermentation and it was setting on the counter and i noticed it started working on its own!!

[NZChris]

The SG will tell you more about what's happening than any guesses we can make.

[still_stirrin]

Its technically dunder i guess from a sweet feed mash but it had finished out close to 1 so there was little sugar in it...

Nope...dunder is “backset” from a rum run. It’s the liquid from the bottom of your boiler after the distillation is done.

“Lees”, or trub (from a sweet feed ferment), is the sediment left behind in your fermenter. It most certainly could restart bubbling when your beer is racked off due to the concentration of yeast population and aerobic activity of racking the beer off. But, without more fermentable material, it won’t bubble long.
ss

[jonnys_spirit]

Interested if OP is referring to actual backset from the still run or lees/trub from the ferment. You might add either into next generation ferment depending on what you do but backset has been cooked/boiled for a while and shouldn't spontaneously referment. I guess it's conceivable that the original ferment didn't finish and the backset may have sugars left in it which could be exposed to wild yeast and start fermenting again but depending on the acidity of the backset it may also prevent yeast activity... Still interested in what happened here....

Cheers!
-jonny

[zharleydave]

Its technically dunder i guess from a sweet feed mash but it had finished out close to 1 so there was little sugar in it...

Nope...dunder is “backset” from a rum run. It’s the liquid from the bottom of your boiler after the distillation is done.

“Lees”, or trub (from a sweet feed ferment), is the sediment left behind in your fermenter. It most certainly could restart bubbling when your beer is racked off due to the concentration of yeast population and aerobic activity of racking the beer off. But, without more fermentable material, it won’t bubble long.
ss

well rum is a molasses produced product and sweetfeed has molasses in it so backset or dunder same thing different product I get that !! just was inquiring if the strong fermentation in a gallon of back set was normal or not but im guessing from responses its not. It has a pleasent odor so i will use it and see what it produces ! Thanks for the reply !!!

[zharleydave]

Interested if OP is referring to actual backset from the still run or lees/trub from the ferment. You might add either into next generation ferment depending on what you do but backset has been cooked/boiled for a while and shouldn't spontaneously referment. I guess it's conceivable that the original ferment didn't finish and the backset may have sugars left in it which could be exposed to wild yeast and start fermenting again but depending on the acidity of the backset it may also prevent yeast activity... Still interested in what happened here....

Cheers!
-jonny

Its backset for sure thanks for the reply its bubbling away like a yeast ferment still , smells good so im going to use it

[zed255]

I'm sure having stillage, spent beer, dunder, backset or whatever left over from a distillation start fermenting is possible, just needs to have some residual sugar and exposure to a little yeast. A brandy I just did had a mix of wines, some quite sweet. The stillage from that run still tasted sweet and had a gravity of 1.035; I was tempted to see if it would ferment out but decided against it.

Of course, it could be something bacterial too chomping away at what is left behind.

[richard1]

Not sure what you are making but I would not advise using backset in fermentation. Basically you will potentially lose fermentation control with all sots of infections coming into play.

Rather use the backset in a mash and you will get better PH control as well as creating the basis for yeast nutrients.