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Fermentation Stuck - Brew Fixes or Ideas to Restart

Post #1 made 9 years ago
by bworek1
I have done 3 BIAB recipes and my FG has come in high on all of them. I cannot figure out what I am doing wrong. For this recipe I did a fly sparge and my OG was at 1.054 when done. Its now been 1.5 weeks fermentation has stopped at 1.024 (same gravity reading for 2 days). Should add more yeast, amylase or just let it sit longer?

Measured gravity readings with refractometer and hydrometer

Recipe

Original Gravity (OG): 1.055
IBU's (Tinseth): 43
ABV%: 5.32

Efficiency into Kettle (EIK): 79.7 %
Efficiency into Fermentor (EIF): 68.3 %

Times and Temperatures

Mash: 90 mins at 66.7 C = 152 F
Boil: 60 min
Ferment: 28 days at 19 C = 66.2 F

Volumes & Gravities

Total Water Needed (TWN): 31.58 L = 8.34 G
Volume into Kettle (VIK): 29.33 L = 7.75 G @ 1.045
End of Boil Volume - Ambient (EOBV-A): 23.18 L = 6.12 G @ 1.055
Volume into Fermentor (VIF): 19.87 L = 5.25 G @ 1.055
Volume into Packaging (VIP): 18.4 L = 4.86 G @ 1.014 assuming apparent attenuation of 75 %

The Grain Bill (Also includes extracts, sugars and adjuncts)

77.8% American Two-Row 4186 grams = 9.23 pounds
11.1% Crystal 20L 598 grams = 1.32 pounds
8.3% Flaked Oats 448 grams = 0.99 pounds
2.8% Red Wheat 149 grams = 0.33 pounds

The Hop Bill (Based on Tinseth Formula)

5.5 IBU Cascade Pellets (5.5%AA) 9.6 grams = 0.339 ounces at 60 mins
10.8 IBU Amarillo Pellets (8.9%AA) 19.2 grams = 0.678 ounces at 20 mins
6.7 IBU Cascade Pellets (5.5%AA) 19.2 grams = 0.678 ounces at 20 mins
8.5 IBU Simcoe Pellets (14%AA) 9.6 grams = 0.339 ounces at 20 mins
3.6 IBU Amarillo Pellets (8.9%AA) 19.2 grams = 0.679 ounces at 5 mins
2.2 IBU Cascade Pellets (5.5%AA) 19.2 grams = 0.679 ounces at 5 mins
5.6 IBU Simcoe Pellets (14%AA) 19.2 grams = 0.679 ounces at 5 mins

Mash Steps

Mash Type: Pure BIAB (Full Volume Mash) for 90 mins at 66.666666 C = 152

Fermentation& Conditioning

Fermention: 2 Packets Wyeast - 1056 American Ale for 28 days at 20 C = 68 F
**Yeast Nutrient Used**
Last edited by bworek1 on 18 Sep 2014, 23:09, edited 1 time in total.

Post #2 made 9 years ago
by mally
Do you have more than one thermometer Bworek?

Maybe your current one is reading lower than actual?
I don't know anything about 1056 (is this US-05)? regarding attenuation but 1.024 does seem high.

I have tried amylase once (well pilsner enzyme), never again :nup:
In hindsight I would have preferred the higher FG beer :smoke:

One thing I do that can help rouse yeast is to rotate the fermenter back and forth. This can rouse without splashing (introducing oxygen) or removing the lid. Dunno if this could work in your situation? :think:
G B
I spent lots of money on booze, birds and fast cars. The rest I squandered
I've stopped drinking, but only when I'm asleep
I ONCE gave up women and alcohol - it was the worst 20 minutes of my life
    • SVA Brewer With Over 100 Brews From Great Britain

Post #4 made 9 years ago
by mally
If you have only tested the thermometer at 0c & 100C it can still be off in the middle. :o
See this post here.

Pilsner enzyme seems to strip all flavour and mouthfeel and leave you with something quite alcoholic/hot & unpleasant.
I have only ever tried it once, so it is only anecdotal & not a scientific study. However, I think I would only ever try it again if I became diabetic!
Last edited by mally on 19 Sep 2014, 01:08, edited 1 time in total.
G B
I spent lots of money on booze, birds and fast cars. The rest I squandered
I've stopped drinking, but only when I'm asleep
I ONCE gave up women and alcohol - it was the worst 20 minutes of my life
    • SVA Brewer With Over 100 Brews From Great Britain

Post #7 made 9 years ago
by Mad_Scientist
Your specific gravity should be a 1.006 on the hydrometer and an ABV of 6.4%. :)

What was your starting Brix before adding yeast, something like, "13.2" or "13.4"?
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Fermentation Stuck - Brew Fixes or Ideas to Restart

Post #10 made 9 years ago
by Contrarian
If it is still sitting at 1.024 on a hydrometer reading (refractometer reading needs adjustment post fermentation) there's a couple of things that usually do the trick.

Give the fermenter a gentle swirl to rouse the yeast, you can even give it a gentle stir with a sterilized spoon but that increases possible risk of infection.

Increase the fermentation temperature a few degrees. Sometimes going from 18 up to 22 or 23 degrees can encourage the yeast to finish the job with minimal impact on flavour.

If these don't work you can take a sample and put it in a separate bottle and give it a good shake whenever you remember and keep warm. This should finish more quickly and give you an idea of your final possible gravity.

Dissolve 100g of table sugar to boiling water, dissolve and then add to the fermenter. This has kick started a stuck ferment for me before.

Hope this helps!

Post #11 made 9 years ago
by Mad_Scientist
...and your hydrometer is reading a 1.024 currently, that doesn't make any sense to me?

I would tend to trust the refractometer Brix reading of 6.2, at this time.

Since you posted a BIABacus report, I feel that you have reached a terminal gravity, but would let it go a total of 2 weeks, imo.


How does it taste?
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Post #12 made 9 years ago
by bworek1
I actually didn't take a reading with my hydrometer. I will be doing that tonight.

My first reading was with a hydrometer and got a OG reading of 1.054. My FG reading was with my refractometer and it was at 6.2 Brix.

Post #13 made 9 years ago
by cwier60
bworek1 wrote:I actually didn't take a reading with my hydrometer. I will be doing that tonight.

My first reading was with a hydrometer and got a OG reading of 1.054. My FG reading was with my refractometer and it was at 6.2 Brix.
Your FG is more like 1.010. You have to correct your Brix reading once alcohol is present. The good news is your beer is fine and has attenuated about as expected with 1056.
Mad_Scientist wrote:Your specific gravity should be a 1.006 on the hydrometer and an ABV of 6.4%. :)

What was your starting Brix before adding yeast, something like, "13.2" or "13.4"?
The calculator MS is using is inaccurate and calculates a FG that is too low. Every brewer should use the calculator developed by Sean Terrill; you can use it online or download a spreadsheet version. I believe that it is the most accurate model currently available. I recommend using Sean's default wort correction factor of 1.04, which accounts for the difference between wort and wine must (and is explained on his website). If you assume that your original hydrometer reading of 1.054 is accurate, then adjust the starting Brix to 13.87 to get this value; if the correction = 1.00, then the corresponding Brix would be the 13.33 value that most converters report*. If you use these values, the calculated FG is 1.0102. I expect that you will find this to be accurate within ~+/- 0.001 SG, which is about the ability to resolve a reading on a hydrometer unless you have a precision one with a reduced scale like 0.98-1.02.

Try taking both hydrometer and refractometer readings of both OG & FG a few times to check the calculations. Of course, like all brewing calculators, there are many variables that result in imperfect results.

* I expect that this would mean that you would get an initial (OG) refractometer reading of 13.87 if your hydrometer reading was 1.054. This differs from the SG reading on a "corrected" refractometer, which converts based on the 1.0 wort correction factor.
Last edited by cwier60 on 19 Sep 2014, 12:03, edited 1 time in total.
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Post #14 made 9 years ago
by bworek1
Mad_Scientist wrote:Your specific gravity should be a 1.006 on the hydrometer and an ABV of 6.4%. :)

What was your starting Brix before adding yeast, something like, "13.2" or "13.4"?
Ok, so my hyrdometer reading came in at 1.008. Is that weird? Is the refractometer supposed to be that far off?
Last edited by bworek1 on 19 Sep 2014, 21:27, edited 1 time in total.

Post #15 made 9 years ago
by cwier60
bworek1 wrote:
Mad_Scientist wrote:Your specific gravity should be a 1.006 on the hydrometer and an ABV of 6.4%. :)

What was your starting Brix before adding yeast, something like, "13.2" or "13.4"?
Ok, so my hyrdometer reading came in at 1.008. Is that weird? Is the refractometer supposed to be that far off?
No, it's not weird, and why you need to correct the Brix reading in the presence of alcohol. Sean Terrill explains this on his Refractometer Estimates of Final Gravity page:

A refractometer is one of the most useful tools a brewer can have. It allows for near-instantaneous measurements of specific gravity, without having to compensate for or adjust sample temperature or withdraw a large volume of wort/beer (a significant concern at homebrew scales). There are a few issues associated with accurately using a refractometer for brewing, though. First, a refractometer does not actually measure specific gravity, or sugar content. Instead it simply projects a line through a reticle, and relies on the fact that the refractive index of the fluid will move a line up and down the reticle. For a simple sucrose solution (the refractometers common to homebrewers are “borrowed” from the wine industry) the refractive index depends only on the sugar content and the temperature. Automatic temperature correcting (ATC) refractometers use a bimetal strip to cancel out the temperature variable (within a given range), meaning that the reticle can be marked directly in units of sugar content. Brewers’ wort, however, is not a sucrose solution, and so a “wort correction factor” must be applied. Generally this is done by dividing the refractometer reading by 1.04.

The second, more intractable problem with using a refractometer to determine specific gravity is that once fermentation begins, the beer becomes a three-part solution: sugars, water, and alcohol. There is no longer fidelity of measurement – that is to say, there can be more than one specific gravity that will correlate to the same refractive index. Generally speaking, however, only one of the potential data points will be sensible for a real beer. Making that assumption, it should be possible to develop a correlation between the measured refractive index and the actual gravity of the beer, as long as the alcohol content can be estimated. This means that if both pre- and post-fermentation readings are taken, the FG can be predicted.

BTW, is your final Brix reading still 6.2 or slightly lower? If it's 6.2, then it still predicts a FG that is within 2 points of your hydrometer reading.
Last edited by cwier60 on 19 Sep 2014, 22:15, edited 1 time in total.
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