Homebrewers Association | AHA Forum

General Category => Extract/Partial Mash Brewing => Topic started by: kharn74 on November 15, 2012, 10:49:02 AM

Title: Final Gravity is way off from what the book is saying
Post by: kharn74 on November 15, 2012, 10:49:02 AM
I am doing a Gulden Draak clone from the "Clone Brew" book.  It is a 5 gallon extract version.  My original gravity was 1.109 and it is supposed to be around 1.025 when finished.  It is sitting at 1.054 and has been at that reading for a week?  This is my first beer that I have not hit the recommended final gravity.  Is It OK to bottle or should I wait?
 :o
Title: Re: Final Gravity is way off from what the book is saying
Post by: mainebrewer on November 15, 2012, 01:01:17 PM
How long has it been since you pitched the yeast?
Title: Re: Final Gravity is way off from what the book is saying
Post by: narvin on November 15, 2012, 02:54:21 PM
Predicting FG is a hard thing to do.  Wort fermentability varies, and some extract is less fermentable than others, so the beer could just be done.  Another factor that probably compounded the problem is the high OG.  Unless you made a really big starter (see mrmalty.com) and aerated well, the yeast may have pooped out.  I've never had much luck restarting a stuck fermentation, but others may have advice for that.
Title: Re: Final Gravity is way off from what the book is saying
Post by: Joe Sr. on November 15, 2012, 03:17:43 PM
Even low-fermenting extract should get lower than 1.054.

Try getting the yeast back into suspension (rock the carboy, or gently stir with a racking cane).  Try warming it up.

You could also try pitching a large active starter to get it going again.

You might want to pull a small sample and dump a whole packet of dry yeast into it to see how far it will ferment out.  This will tell you what should be achievable with the balance of the beer.
Title: Re: Final Gravity is way off from what the book is saying
Post by: morticaixavier on November 15, 2012, 03:45:46 PM
details?

Recipe? yeast variety and quantity pitched? ferm temp?
Title: Re: Final Gravity is way off from what the book is saying
Post by: kramerog on November 15, 2012, 04:04:44 PM
You could also try pitching a large active starter to get it going again.

You might want to pull a small sample and dump a whole packet of dry yeast into it to see how far it will ferment out.  This will tell you what should be achievable with the balance of the beer.

Rehydrate dry yeast in warm water and add to 3/4-gal of the aerated beer.  Pitch in your beer after that.   If you got the phenolicy character you want already, I would try Nottingham which tends to rip through big beers.  If not, try T-58 although I'm not so sure of its prowess in big beers. 

What type of malt syrup did you use?  Irek's which may no longer be sold anyway had lot's of non-fermentables and was designed to be used with lots of sugar.
Title: Re: Final Gravity is way off from what the book is saying
Post by: a10t2 on November 15, 2012, 04:31:40 PM
Have you calibrated your hydrometer?
Title: Re: Re: Final Gravity is way off from what the book is saying
Post by: Mark G on November 15, 2012, 04:54:14 PM
Have you calibrated your hydrometer?
Or are you using a refractometer?
Title: Re: Re: Final Gravity is way off from what the book is saying
Post by: Slowbrew on November 15, 2012, 05:51:35 PM
Have you calibrated your hydrometer?
Or are you using a refractometer?

Good question! 

Roughing out the numbers he gave (converting back to brix and then running through the spreadsheet) would convert to around 1.023 if he is using a refractometer. 

Paul
Title: Re: Final Gravity is way off from what the book is saying
Post by: bazowie on November 15, 2012, 07:07:47 PM
I got stuck at 1.035 from 1.095, i rehydrated dry as already mentioned and repitched this got me down to 1.016. It freaked me out at first but i didnt want to loose the beer so i gave it a go and it worked. I just tapped the last keg after 13 months and it turned out to be one of the better stouts ive made.
Good luck.
Title: Re: Final Gravity is way off from what the book is saying
Post by: kharn74 on November 15, 2012, 10:13:41 PM
I am using a Refractometer with ATC that has been calibrated.  The brix that I got was 14.  Did I convert it wrong?  This is my first time using it.

Title: Re: Final Gravity is way off from what the book is saying
Post by: morticaixavier on November 15, 2012, 10:34:06 PM
I am using a Refractometer with ATC that has been calibrated.  The brix that I got was 14.  Did I convert it wrong?  This is my first time using it.

when in presence of alcahol refractometers do not give accurate readings. Sean Terrill has a good tool for converting the results.

as slow brew pointed out, with that taken into account your beer is actually at 1.023
Title: Re: Final Gravity is way off from what the book is saying
Post by: Slowbrew on November 15, 2012, 10:34:30 PM
I am using a Refractometer with ATC that has been calibrated.  The brix that I got was 14.  Did I convert it wrong?  This is my first time using it.

What was the OG reading in Brix and what was you FG reading in Brix?  The OG can be roughly converted by multiplying Brix(4).  The FG reading needs to be adjust to account for alcohol in the solution which throws off the light refraction and will make you think your gravity is really high.

Use this site to calculate the real FG value.  http://seanterrill.com/2012/01/06/refractometer-calculator/

Paul
Title: Re: Final Gravity is way off from what the book is saying
Post by: morticaixavier on November 15, 2012, 10:38:37 PM
I am using a Refractometer with ATC that has been calibrated.  The brix that I got was 14.  Did I convert it wrong?  This is my first time using it.

What was the OG reading in Brix and what was you FG reading in Brix?  The OG can be roughly converted by multiplying Brix(4).  The FG reading needs to be adjust to account for alcohol in the solution which throws off the light refraction and will make you think your gravity is really high.

Use this site to calculate the real FG value.  http://seanterrill.com/2012/01/06/refractometer-calculator/

Paul

did the math for you (well the internet did the math)

Looks like your real reading at this point is 1.014 pretty good. have you tasted the samples? I imagine they taste pretty good no?
Title: Re: Final Gravity is way off from what the book is saying
Post by: kharn74 on November 15, 2012, 10:57:15 PM
Thanks for the help, guess I just need to study up on using a refractometer.  The Sean Terrill web site is now on my Favorites list.  Yes, the samples taste great.
Title: Re: Final Gravity is way off from what the book is saying
Post by: a10t2 on November 16, 2012, 12:08:03 AM
For what it's worth, the calculator probably won't do a *great* job with an OG that high. It should get you in the ballpark though.
Title: Final Gravity is way off from what the book is saying
Post by: majorvices on November 16, 2012, 02:09:41 AM
I always use a hydrometer for the FG. I can never get a correct reading even with the correction on my refracto. In fact, I've gone back to using my hydrometer full time again. I was starting to get high readings every time I used my refracto, and it was calibrated correctly.
Title: Re: Final Gravity is way off from what the book is saying
Post by: denny on November 16, 2012, 04:43:25 PM
I always use a hydrometer for the FG. I can never get a correct reading even with the correction on my refracto. In fact, I've gone back to using my hydrometer full time again. I was starting to get high readings every time I used my refracto, and it was calibrated correctly.

Yeah, I've got 2 refractometers but I've given up on them and gone back to a hydrometer for everything.