Stuck fermentation--beyond frustrated

Could it be related to 17% of the malt bill isn't fermentable?

 

Are you rehydrating the yeast? If not, you are killing a portion of the yeast when you pitch. I don't know the solution but it seems like it is a fermentation issue, which usually boils down to having enough healthy yeast.

 

Use less 02 next time. You are using more than enough for a 5 gallon high gravity batch in a 1 gallon batch. Don't go full blast either. Open it up just enough to see bubbles. Do 10 seconds the first day and 15 seconds the second day using low pressure.

If that and rehydrating the yeast doesn't work, then you are cursed and should try brewing something that isn't 12%.

 

no...you mean higher FG, right?

If I were the OP, I'd just pour the wort back and forth vigorously (easy for a 1 gal batch) and use the lightest dme available and possibly replace 10% with sugar. I don't like brewing imperial anything with extract.

 

More unfermentables (roast/caramels) will usually result in a higher FG..unless I'm misunderstanding you

If you are talking about OG, then the OP steeped the roast/caramel so there would only be a slight increase in OG, but not as much as if he had mashed them (slightly more)...if I'm not mistaken

 

Yes, but they will add to the OG nevertheless...sugar is sugar...whether it is being extracted , or is already converted (caramel)...the roast, not so much,.

 

This is not consistent with tmy understanding of the literature put out by Briess and utilized in brewing software, e.g., extract potentials listed by BeerSmith as follows:
Roasted Barley -- 1.033
Chocolate -- 1.035
C90 -- 1.033

 

I would never have guessed the chocolate had the highest ppg

edit: slightly lower #s here:
Cheers http://www.beersmith.com/Grains/Grains/grain_33.htm

(although Briess not specified)
My wife's out of town...can you tell? : )

 

Oh...it wouldn't be the first time we were outside the standard deviation : $
Yes, I would take Briess' #s before Beersmith, but Briess' # aren't all that accurate either (probably)
Bottom line: color and flavor are not the only things you get out of most dark malts...however miniscule the contribution may seem..or not ; )

 

Perhaps @VikeMan can chime in, as he's been assimilating data on malts (and other stuff) for his brewcipher program. My guess is he has sources for extract potential of roasted malts that he uses in the program.

 

Isn't the explanation as simple as unfermentable grains don't produce unfermentable sugars? Unfermentable sugars which add to the gravity points come from other sources.

 

Let me just start by saying, " I'm drinking"...specific gravity is about density...and sugar has more density than water...but other things are more dense than water also (please, no puns) : )

 

Let me just start by saying, hops are magical ingredients : ) ....yes, "appreciably" is kind of like "significant"...but different...I can "appreciate" coffee or tea (or hops) for their flavor components...but do they contribute "significantly" to the OG of their respective beverages?...no...but they are "much" appreciated. : )...and besides even carmelized or roasted malts have much more sugar than coffee or tea : )

Eh, what was the question again?
If you are also mind altered, you will understand this. : )

 

Even burnt sugar soaked in water has a higher OG than water...or tea, or coffee ...I am wrong...my bad...I have had terrible coffee that would put a high FG Imperial Stout to shame : )

 

Caramel/Crystal Malts have potentials in the low to mid 30s PPGs. Roasted Barley, Black Patent, and Chocolate malts are typically in the mid 20s. Remember, that's potential. Mash (or steep) efficiency will result in lower yields.

There are a couple things happening here. First, Crystal/Caramel (especially non-Crystal caramel malts) do have a bit of unconverted starches. (So mashing (with adequate enzymes) results in higher yields than steeping.) Second, and more importantly, some of the non-sugar caramelized/roasted compounds are soluble. So they contribute gravity. For convenience, we typically think of gravity as only dissolved sugars, but it's more than that. The gravity from caramel/crystal/roasted malts (some fermentable sugars, some non-fermentable compounds) is partially fermentable. The darkly roasted grains contribute mostly non-fermentable (but still some gravity increasing) stuff. But a fairly significant portion of Caramel/Crystal malts' gravity contribution is fermentable.

Off the top of my head, I'd say look at Greg Doss' grain fermentability data for a quantitative lesson. I drew on it pretty heavily for BrewCipher. But Greg wasn't the first one to notice this. I think it goes back at least as far as Palmer's early "How to Brew" version. IIRC, Palmer showed yield tables for specialty malts.

 

Yeast starter doesn't seem to of been mentioned, unless I missed it. Although 1/2 pack seems reasonable of a pitch rate for a 1 gallon batch, you've got much more control ensuring good healthy yeast with a starter.