Building up the alcohol?

[bobbo]

OK, so keep in mind that this question originated in a thread about making hooch with Kool-Aid and bread yeast. So EACs please understand that this is for entertainment purposes only. It just got me curious on how the fermentation process works, and I wanted to move my question so that I didn't hijack the thread.

Just a thought.... So lets say the attennuation of bread yeast is 70% (no idea if this is true, but let's assume for the sake of my question). A hooch concoction with an OG of 1.100 would get down to 1.030 before the yeasties are done. I think that's around 9% alcohol. Now what if you pitched more yeast? Would they get started on the remaining 1.030 sugars and bring the gravity down to 1.009 (again assuming 70% attenuation)? That would get the ABV up to almost 12%. Better yet, before re-pitching the yeast into the 1.030 solution, dissolve a bunch more sugar into a minimal amount of water or kool-aid and add that in. Doing this, it would seem like you could bump the gravity of the hooch way back up before the new batch of yeast gets started. I don't know the exact math but it seems like you could build up a lot of alcohol this way. Repeat it several times, and you could get % into the 20s or 30s, it seems. What do you think? Would it work? Or would the amount of alcohol in the solution prevent the new yeast from doing their thing on the new sugars?

Someone said it wouldn't work to re-pitch fresh yeast in the already fermented 1.030 solution. Why not? Is it because of the pre-existing alcohol? I mean, if you started fresh with an OG of 1.030, it would work fine. Again, I'm not trying to be difficult, I'm just curious.
And what about adding a concentrated sugar solution to the already fermented mix before pitching fresh yeast? Would that work to begin the fermentation again?
Geez, I almost feel like I'm doing something wrong asking questions like this. Please don't kick me out of the forums!

Bob

 

[Beerrific]

The specific gravity (measure of the sugar content) has nothing to do with the yeast working. If there is sugar they will metabolize it and make ethanol+CO2. At the same time, ethanol is toxic to yeast (just like it is to humans). Too much alcohol will kill the yeast. Adding a concentrated sugar solution will add sugar but tha alcohol is still there and will kill the yeast. This is true even if you introduce fresh yeast. Now, the amount of alcohol yeast can tolerate depends on the strain. The highest I have heard of is champagne yeast at 15%.

To go higher than that you have to distill.

 

[bobbo]

The specific gravity (measure of the sugar content) has nothing to do with the yeast working. If there is sugar they will metabolize it and make ethanol+CO2. At the same time, ethanol is toxic to yeast (just like it is to humans). Too much alcohol will kill the yeast. Adding a concentrated sugar solution will add sugar but tha alcohol is still there and will kill the yeast. This is true even if you introduce fresh yeast. Now, the amount of alcohol yeast can tolerate depends on the strain. The highest I have heard of is champagne yeast at 15%.

To go higher than that you have to distill.

Ah, now I see. Thanks for the great explanation!

 

[FlyingHorse]

The highest I have heard of is champagne yeast at 15%.

To go higher than that you have to distill.

White Labs claims the WLP099 High Grav will go to 25%

 

[Beerrific]

White Labs claims the WLP099 High Grav will go to 25%

Wow.

Is this what DFH uses for their 120 min IPA?

 

[_Edge]

Wow.

Is this what DFH uses for their 120 min IPA?

I know sam adams utopias uses champagne yeast (it has 20% abv)

 

[Brewing Clamper]

Sometimes the sugars still left in the brew are unfermentable by the yeast without further modification. If the fermentation from 1.100 to 1.030 stopped because of exhausted yeasties, repitching a new batch would allow the fermentation to continue, as long as the yeast is tolerant to the high level alcohol and the remaining sugar is fermentable.

 

[the_bird]

I know sam adams utopias uses champagne yeast (it has 20% abv)

They have their own "ninja yeast" that they have developed, I'm pretty sure in-house. I suspect it's a lot closer to the WLP099 than a champagne yeast.

Distiller's yeast will get you to 25%, as well - but there's a reason that yeast is designed for distillers. Not going to give you a very drinkable product.

 

[CBBaron]

Sometimes the sugars still left in the brew are unfermentable by the yeast without further modification. If the fermentation from 1.100 to 1.030 stopped because of exhausted yeasties, repitching a new batch would allow the fermentation to continue, as long as the yeast is tolerant to the high level alcohol and the remaining sugar is fermentable.

If a beer fermented from 1.100 to 1.030 in moderate temperatures, most likely it stopped due to unfermentable sugars. Adding more yeast is not going to help. Adding a concentrated sugar solution solution will cause more fermentation but will still stop somewhere above 1.030.

Most beer yeast will tolerate 12%-15% alcohol. Champagne yeast may tolerate a little higher but is also more efficient in sugar conversion, therefore making a dryer beer (sometimes desirable). White labs has a highly tolerant yeast that is good to well over 20% but you have to treat it nice. You have to add concentrated wort to the fermentation at regular intervals to get that high. Trying to ferment a wort approaching 1.2 OG is probably not going to work.

Making a big beer that tastes good is an activity that is quite commonly discussed on HBT, but trying to make your hooch stronger will get alot of backlash. Look at threads on IIPA, Barley Wines and Belgian Strong Ales. Even BYO had an article on someone who produced an AG beer with 22% ABV. (Search their site for the article as it probably answers most of your questions)

Craig

 

[bobbo]

Making a big beer that tastes good is an activity that is quite commonly discussed on HBT, but trying to make your hooch stronger will get alot of backlash.

Don't worry, I have no intentions of actually trying this - I was just reading the recently started hooch thread (which isn't meant to be taken too seriously, btw) and since one of the goals is high ABV, it got me curious as to whether something like that would work.

Cheers!
Bob

 

[Orfy]

Don't worry, I have no intentions of actually trying this - I was just reading the recently started hooch thread (which isn't meant to be taken too seriously, btw) and since one of the goals is high ABV, it got me curious as to whether something like that would work.

Cheers!
Bob

It wasn't meant to be a hooch thread I was suggesting a dumping ground for all the hooch threads.