Fermentation Issues

[JCasey1992]

Hi guys,

I have had a Belgian dubbel in the primary for about a week now. The recipe has a target abv of 7.8%. I probably shouldn't have but out of sheer boredom, I checked the gravity with my refractometer and if my calculations are correct, I am way off the mark on this one. Target OG was 1.078 and I reached a 1.074 which seems good but nine days in the brix reading is down from 18 to about 8 which based on the calculators I've used, would put me approximately 2 percentage points too high on the abv and too low on the gravity. Can someone please explain this to me? I normally wouldn't worry about this but given that this recipe has only been fermenting for about nine days and it's already reading this way on my refractometer, I can't help but be concerned.

The recipe can be found here: http://barleyhaven.com/dubbel-home-brew-kit-all-grain.html

Thank you,
Casey

 

[stpug]

Whenever I find an "unbelievable" corrected refract reading then I resort to a hydro for confirmation.

 

[JCasey1992]

would put me approximately 2 percentage points too high on the abv

Whoops! make that about 1.2 percentage points too high.

 

[kh54s10]

I would suggest taking a reading with a hydrometer for a more accurate number. Alcohol skews the reading with a refractometer and correction software is suspect at being accurate.

You say you are 2 points low on gravity. How do you figure that? There are so many things that will affect your final gravity. The yeast will consume the sugars until they are gone. They don't know anything about the recipe saying that FG should be 1.012. The FG could range quite a bit. .002 low is inconsequential.

So I see the OG at 1.074 and current SG at 1.031. It is not nearly done and it calculates at only 5.64 ABV which seems really weak for a belgian dubbel.

Wait another week then take a hydrometer reading.

 

[JCasey1992]

I would suggest taking a reading with a hydrometer for a more accurate number. Alcohol skews the reading with a refractometer and correction software is suspect at being accurate.

You say you are 2 points low on gravity. How do you figure that? There are so many things that will affect your final gravity. The yeast will consume the sugars until they are gone. They don't know anything about the recipe saying that FG should be 1.012. The FG could range quite a bit. .002 low is inconsequential.

So I see the OG at 1.074 and current SG at 1.031. It is not nearly done and it calculates at only 5.64 ABV which seems really weak for a belgian dubbel.

Wait another week then take a hydrometer reading.

Thanks. As a brewer who is less than a year in, I appreciate your patience. I must be reading the refractometer calculator wrong. I have been using this one here: http://www.northernbrewer.com/learn/resources/refractometer-calculator/

Please let me know if you know of a better method for calculating gravity and ABV. Also, I miscalculated. It's more like 1.2 abv points too high.

 

[JCasey1992]

Update: I found another calculator that seems far better for what I'm trying to accomplish. This makes the numbers mentioned above completely moot. Thank you for the help.

 

[kh54s10]

I use Brewers Friend. I converted your brix to SG then used the ABV calculator. I see that the recipe calls for a 156 degree mash. Seems high to me. I also see it calls for an ABV of 7.8% At 18 brix OG and 8 Brix FG you only have 5.64% ABV so I think you are 2.16% low.

Again wait another week and take a gravity reading with a hydrometer. This beer has not finished fermenting yet.

 

[JCasey1992]

I use Brewers Friend. I converted your brix to SG then used the ABV calculator. I see that the recipe calls for a 156 degree mash. Seems high to me. I also see it calls for an ABV of 7.8% At 18 brix OG and 8 Brix FG you only have 5.64% ABV so I think you are 2.16% low.

Again wait another week and take a gravity reading with a hydrometer. This beer has not finished fermenting yet.

Thank you. I think it was just a matter of panic and impatience from me. I've seen people who gave dubbels eight whole weeks to ferment and it's only been nine days. I'm confident that the ABV will go up with enough time. It also doesn't help that I was using the calculator incorrectly lol. Thank you.

 

[RM-MN]

Thank you. I think it was just a matter of panic and impatience from me. I've seen people who gave dubbels eight whole weeks to ferment and it's only been nine days. I'm confident that the ABV will go up with enough time. It also doesn't help that I was using the calculator incorrectly lol. Thank you.

I doesn't take 8 weeks to ferment but it won't hurt to wait that long. Whether the time is spent in the fermenter or in bottles or kegs doesn't matter a lot, your dubbel. being a high gravity beer, will take time to mature. I'd expect it to take 2 to 4 months to get really good.:rockin:

 

[chickypad]

I use Sean Terrill's calculator which seems to be the most accurate, Brewer's Friend also uses his formula. You should really figure your wort correction factor as explained on the page, but roughly with your numbers it looks like about 1.074 and 1.011, for an ABV around 8.71%. As mentioned you can double check with a hydrometer but I've found that calculator close enough for my purposes.
I agree with RM-MN the fermentation is likely done but letting it age a bit would be a good thing.