Dunder potential

[realtree71]

So i had a hard time getting my alcohol potential down near 1.00.
I ran 13 gal low and slow and got about 2gal 155-110 proof.

Be cause of time i pushed the 110 and under out.

This morning for the hell of it i checked sp grav. The dunder has a potential of about 10%.

Should i just repitch with yeast and see what happens?

Im currently reboiling yesterdays dunder to squeeze out any remaining alcohol.



Thoughts

[realtree71]

Original wash for 13 gal had about 4 gal of grade A fancy molasses.

[bilgriss]

I suspect that the pH of that mess is so low you won't have much luck restarting it.

An alternative would be to use a portion of it in a subsequent ferment.

[MooseMan]

Yeah keep a gallon back and add to next rum ferment, for sure.

[jonnys_spirit]

Non-fermentables will keep the gravity above 1.000 even when all the fermentables are converted to ETOH.

Cheers!
-j

[Bolverk]

10% is a lot... Was your wash done fermenting?

What was your starting and ending gravity?

Molasses has a lot of unfermentables. Using golden barrel blackstrap it's not uncommon for me to still have a gravity of 1.030 +/- in an all molasses batches dunder.

[realtree71]

I suspect that the pH of that mess is so low you won't have much luck restarting it.

An alternative would be to use a portion of it in a subsequent ferment.

I checked ph this morning on 4 -5gal pales. Lowest was 4.96 highest was 5.03.

[still_stirrin]

… This morning for the hell of it i checked sp grav. The dunder has a potential of about 10%…

Thoughts?

You (tried to) measure the “dunder”, ie - what’s left in the boiler AFTER a run. What tool did you use?

A brewing hydrometer measures density relative to water (SG = 1.000), so if you measure the dunder and it yields a gravity greater than 1.000, it is because what was in the original boiler charge has concentrated what DID NOT boil over to the product condenser. The density will go up! And it is NOT because of “alcohol potential”.

And you can’t use a Proof & Traille hydrometer (alcometer) either because it measures the density of an alcohol/water mixture where the alcohol density is LESS than water. Therefore, as the density is greater (approaching water) indicates less alcohol in the solution. If there is other stuff, like sugars or acids in the dunder, the density would be greater than water, so the P&T hydrometer would not sink into the liquid.

Bottomline, I question if you even know what you’re doing here (with your question). And as already noted, dunder from a wash is usually way too acidic to support any additional fermentation. It is exactly what is used to “sour” a subsequent mash, and you need to be mindful of how much of it you use to sour the mash, as dunder (or backset) is typically very acidic.

I also wonder why you stopped collecting off the still when the “proof at the spout” was still at 50-55%ABV. It certainly indicates you left alcohol in the boiler.

I usually collect down to where the “proof at the spout” is 10%ABV, or less. Sure, it may be wholly (holy?) tails, but I collect in separate jars just to squeeze as much alcohol out of the wash. I can make appropriate cuts after the wash has been run, so I go as far as I can. I don’t make cuts when I run, but I do collect into a posse of separate jars for this reason.

So, how do you know the dunder has a “potential alcohol” remaining of 10%ABV?
ss

[Setsumi]

+1 on SS, you measure density of all the junk that could not ferment.

[kennstminet]

Alcohol has a lower density than water.
Dunder has a higher density than water.
The alcohol produced by fermentation will lower the combined density.
However the effect of the alcohol is not strong enough to overcome the high density of the dunder. The SG will stay higher than the SG of plain water.
There is a difference between plain sugar/water washes and washes with appreciable content of high density ingredients like dunder.

[Yummyrum]

Should i just repitch with yeast and see what happens?

Im currently reboiling yesterdays dunder to squeeze out any remaining alcohol.

No point adding more yeast . It had already fermented .
If you stopped stripping run at 110proof (55% ABV) then yes you left a fare amount of alcohol in the boiler.

So your decision to reboil was the correct one .
Just add it to the first collected and then do your spirit run .
Keep enough dunder so you have around 10% of your next wash volume .

And as others have said , you can’t measure alcohol leftbin dunder .
Rum washes made from all molasses will never measure less than 1.030 as Bolverk mentioned and as you keep adding Dunder to subsequent batches , your start and finish gravity’s get higher and higher . I have typical start gravity around 1.120 and finish around 1.060
All molasses washes will always have a start pH close to 5.5 and a finish pH close to 5 .

[realtree71]

Is there a way to post a video in here. All 4 buckets are bubbling away. So there is potential in this. I felt the original batch left to much unconverted sugar.

I videod the airlocks bubbling away

[still_stirrin]

… I felt the original batch left too much unconverted sugar…

Huh???

Sugar does NOT need to be “converted” because it is already SUGAR. What RU thinking?
ss

[jonnys_spirit]

You’d need to check the sugar content in the original molasses and use that to estimate total potential etoh. Then use what you stripped to figure out total etoh you got if you stripped all of it out. Compare those two. The sg readings won’t help much due to unfermentables as mentioned.

-j

EDIT: there is some math involved

[realtree71]

Just ran 10 gal of above mentioned. There did seem to be unfermented sugar left in the molasses run

[Bolverk]

I always run the numbers on my wash so I know if it's stalled or done as well as tasting the wash to see if its bitter tasting.

Take the gravity of your dunder and your starting gravity and you should be able to work out a rough potential and you can confirm it with your final gravity.

Simple example:
Say you're going to make a 4g wash. Blackstrap molasses weighs about 12lb per gallon and is 50% +/- sugar so that's 6lbs of sugar.

You know that a 6lbs of sugar in 3g water is 1.069
https://homedistiller.org/wiki/htm/calc ... gar_sg.htm

Mix your 2.5g water and .5g dunder, take your gravity it should be about 1.015.

The gravity from 1g of blackstrap molasses is going to account for about 1.030.

So you add those and end up with 1.114 +/- as your starting gravity.

So your final gravity should be approx 1.045. (.030 from the new molasses + .015 from the dunder)

This is a gross over simplification but it'll get you close.

[STILL WORKIN]

WOW. Great conversation for a beginner to read. I just switched to rum. It will take a couple weeks to sp run. I have read my ass off for the past 6 months and I think I'm starting to get it.
By far one of the best threads for me .
still_stirin 8:36 explanation was very understandable and important for me.
Thanks HD
STILL WORKIN

[JustinNZ]

Rum’s fun, man! Good luck. The best lesson I’ve learnt is baker’s yeast loves a nice warm wash.

[realtree71]

I wrote above “unconverted sugar” and got flamed. What i ment was i felt there was a potential for alot of sugar went unfermented in the original wash.

I used grade A molasses, 2 gal for a 10gal wash. I used yeast i happened to have which was a white wine yeast. I felt it may have stopped before reaching its potential. I ran it anyway. Got pretty good run from 20 gal total.

I felt the remaining spent wash or dunder tasted pretty sweet still so i threw some bakers yeast in it. Running the 2nd 10gal today. I threw in yesturday run back in and running slow. Getting good product today.