Unexpected high loss of alcohol in wash ?

[Homesweethome]

I am puzzled with a situation. I made a sugar wash with 20 kg sugar mixed into about 120 liter water + baker’s yeast and nutrients added. The fermentation went o.k.
After one week of fermenting the density of the wash was well below 1 and the wash was starting to clear up. I waited for about 10 days after that. Then, just out of curiosity, I measured the alcohol content of the wash and it was only 4% while it should have been about 8% with the amount of sugar and water that I had used.

I am fermenting in a stainless steel barrel that was covered with a loose, but quite well fitting lid. The only explanation that I can imagine now is that the missing alcohol must have escaped via the loose fitting lid. But that much ? Did some of you experience such an high alcohol loss via a loose fitting lid ?

[howie]

how are you measuring the alcohol?
don't think you can measure the alcohol content in a wash accurately.
most folk use the original gravity and final gravity readings to work it out,
ie if OG is 1.080 and FG is 0.990
alcohol is (OG - FG) x 131.25
1.080 - 0.990 = 0.09
0.09 x 131.25 = 11.81%

[Homesweethome]

I measured the alcohol percentage with a glass hydrometer for alcohol (measures between 0 and 35%) and also with an EasyDens, made by Anton Paar, an accurate digital densitometer for alcohol content (measures with an an accuracy of 0.1% and has built in temperature correction).
Both measurements gave the same result of about 4%

[BlackStrap]

Use this one when creating to finishing a Wash
A hydrometer (often called a brewing hydrometer) is calibrated to measure specific gravity (density) based on sugar content in fermented liquids like wine, beer, and cider, requiring two readings—Original Gravity (OG) and Final Gravity (FG)—to calculate Alcohol By Volume (ABV) via a formula.

Use this one after you've run the wash through the still.
An ABV hydrometer, technically known as an alcoholmeter, is calibrated specifically to measure the ratio of ethanol to water in distilled spirits, providing a direct percentage reading without needing a calculation or a starting gravity measurement.

[CuriousRay]

I use a vinometer as it will measure as low as 1-2% and a max of about 25%.

[Homesweethome]

I have a vinometer but didn’t think about using it. No longer possible now because I added more sugar and the wash is fermenting again.

Concerning the proposed method comparing the original gravity with the final gravity: that just gives a calculated abv, isn’t it ? That is basically the same as what I did: I used the HD calculator and fermented until all sugar was used up.
Calculated abv showed more than 8% but when measured the real abv it was 4%. I don’t doubt the calculation method but I also don’t see any reason to doubt my measurements. It is very possible that I just lost a lot of alcohol.

[PalCabral]

An alcohol hydrometer measures gravity in the density of spirits, not fermented wash. There's only one way to accurately measure ABV of a beer/wash and that's by measuring original gravity (OG) before pitching yeast and final gravity (FG) when fermentation is clearly over, then calculating the difference. The EasyDens only figures out if the liquid is a beer/wash or a spirit, then it presents you what gravity your beer is or what ABV your spirit is. It can't calculate the ABV of a beer without knowing OG and FG.

My guess is that you were alright and fully fermented out.

[Salt Must Flow]

I have a vinometer but didn’t think about using it. No longer possible now because I added more sugar and the wash is fermenting again.

Concerning the proposed method comparing the original gravity with the final gravity: that just gives a calculated abv, isn’t it ? That is basically the same as what I did: I used the HD calculator and fermented until all sugar was used up.
Calculated abv showed more than 8% but when measured the real abv it was 4%. I don’t doubt the calculation method but I also don’t see any reason to doubt my measurements. It is very possible that I just lost a lot of alcohol.

Your original water and sugar ratio was adequate. IF it did not fully ferment, it is likely that the PH crashed so it stopped fermenting. You could have adjusted the PH, pitched more yeast and it normally continues fermenting. Often it can continue fermenting without adding more yeast. To keep the PH from crashing is why people add Calcium Carbonate, to buffer the PH as it ferments.

No need to have added more sugar. If the PH did crash, fermentation will likely stop again due to the PH being 3. Now you apparently have too much sugar. It probably needs diluted with water (enough for the amount of sugar you added along with nutrients), raise the PH to 5.2 - 5.6 using Calcium Hydroxide (Pickling Lime), add Calcium Carbonate to buffer the PH and it should continue fermenting. The yeast was stressed so it likely won't be the cleanest wash.

[Homebrewer11777]

If you measured the sugar and water somewhat accurately when you made your wash you should have seen a predictable SG when (if) you measured gravity before pitching the yeast. If gravity was not close to expected you may have needed to stir it some more to dissolve all the sugar.

If it fermented to below 1.000 on that same (or same type of) hydrometer and showed no further activity you were done and should have put it into the still then. Trying to measure ABV in a fermented wort/wash without knowing the starting gravity can be done by distillation...

[Saltbush Bill]

No mention of what exact recipe was used, As SMF suggested above, did it even get to ferment dry.

[SW_Shiner]

No mention of what exact recipe was used, As SMF suggested above, did it even get to ferment dry.

OP did mention that it fermented to below 1.00 gravity.


My guess would be that nothing is wrong. Just OP used the wrong tool for the job.

[Yummyrum]

My guess would be that nothing is wrong. Just OP used the wrong tool for the job.

100% agree SW_Shiner .
You can’t use an alcometer to test wash . It’s not calibrated for that .

It is calibrated for use on distillate only .

[shadylane]

The only explanation that I can imagine now is that the missing alcohol must have escaped via the loose fitting lid. But that much ? Did some of you experience such an high alcohol loss via a loose fitting lid ?

I've never had alcohol evaporate from a wash due to a loose fitting lid. At least not a measurable amount.
My advice is to strip the wash and see how much alcohol you have.
I'd bet good money the problem is due to a faulty measurement.

[Bee]

Run it and let us know what you get.
You can back out a pretty good wash% from the yield of your product.