My Fermentation ALWAYS stops early. HELP!!

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Smokingman

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I must be doing something basically wrong because my fermentation ALWAYS stop early. Here's are examples from a few recent brews:

Barley wine:
OG (target/actual): 1.101 / 1.105
FG (target/actual): 1.022 / 1.050

Blonde Ale:
OG (target/actual): 1.046 / 1.046
FG (target/actual): 1.009 / 1.023

Every single beer I brew makes if about half way before stopping. I've been assuming it's something in my process but I can't figure out what it could be. Here's what I'm doing:


  • All grain brewing
  • I use BeerSmith 2 to figure out volumes and estimated gravitys. I've been hitting dead on target for the OG so I think I got that part right.
  • I use iodine to confirm the mash is complete
  • I've calibrated all my thermometers to a digital reference for accuracy.
  • I do a starter and pitch at the rate recommended by Beer Smith.
  • I use yeast nutrient and oxygen before I pitch.
  • I measure the gravity with a refractometer.
  • I ferment in a converted chest freezer with a thermostat I modified myself that maintains the temperature of the beer within 3 degrees F of the set point of 68F (for ales). I even track the temperature on a strip chart updated every minute to confirm. (http://beer.essercustom.com)
  • I consider the fermentation stopped when the reading doesn't change for 2 weeks. (measured weekly).

Any help would be great. I've been at this problem for months trying to nail down what I'm doing wrong.
 
what are the starting and finishing mash temps? Could you be too hot to start with?
 
I have read recently, and apparently I have one, that there are refractometers out there that the brix scale and the SG scale do not match.

Check the scale by converting the brix to sg and visa versa. Also check it with a hydrometer.
 
Bensiff,
I haven't been using a hydrometer since I got a refractometer. However, when I first got it I would cross check the two for accuracy and found they always agreed.

Badbrew,
I thought that might be a problem so I've been keeping the temps low (150 F -154 F) to be safe and stirring contently until it gets to temp to reduce hot spots. I mash out at 173 F.
 
Smokingman said:
Bensiff,
I haven't been using a hydrometer since I got a refractometer. However, when I first got it I would cross check the two for accuracy and found they always agreed.

Badbrew,
I thought that might be a problem so I've been keeping the temps low (150 F -154 F) to be safe and stirring contently until it gets to temp to reduce hot spots. I mash out at 173 F.
Click to expand...

If you're using your refractometer for FG, there is no way your reading will be accurate without the use of a conversion algorithm-- I prefer this one: http://seanterrill.com/2012/01/06/refractometer-calculator/
 
Smokingman said:
Bensiff,
I haven't been using a hydrometer since I got a refractometer. However, when I first got it I would cross check the two for accuracy and found they always agreed.
Click to expand...

refracto on brew day and never again.:mug:
 
Smokingman said:
Bensiff,
I haven't been using a hydrometer since I got a refractometer. However, when I first got it I would cross check the two for accuracy and found they always agreed.
Click to expand...

From what you said, you are doing everything correctly, there is really no reason for your fermentation to not go to completion so that is driving me to think first that you have a measurement error somewhere and refractometer is a good place to look as they are known to be pretty wonky in the presence of alcohol even with the conversion calculation. You are hitting your gravity so your grain scale is accurate and you said you calibrated your thermometers. However, if that is not it, some other thoughts are checking the age of the yeast and if not the age, the conditions they are being stored. What does your pH look like?
 
badbrew said:
Your refracto is the issue. Go test with a hydrometer asap.:rockin:
Click to expand...

This again, once a month or so someone reports the same issue.

Alcohol disrupts the refractometer readings. You either need to check the final gravity with a hydrometer OR use the refractometer and one of the algorithms to ESTIMATE the final gravity.
 
how about the wather chemistry, it might be an issue to me too,
i agree about the refractometer accurate readings to,
i only use it pre fermentation and after that i use the hydrometer

cheers!
Al
 
how about the water chemistry, it might be an issue to me too,
i agree about the refractometer accurate readings,
i only use in pre-fermentation and after that that i use the hydrometer

cheers!
Al
 
You're all freakin' geniuses!

That was it. I have two beers fermenting right now that I thought had stopped early. I re-checked with a hydrometer and they both hit the target dead on.

I had no idea the refractometer would be that off. When I started a year ago, I was having all kinds of problems with fermentation. The first thing I did was to get a refractometer so I could take more readings using less beer. Since then I've been improving my process thinking I was doing something wrong. I'm sure I was at the beginning, but I didn't realize my measurements were off the entire time.

I guess there's a silver lining to all of this. My process is dead on. My efficiency and attenuation are both excellent.

Thanks to everyone here for all the help!
 
Smokingman said:
You're all freakin' geniuses!

That was it. I have two beers fermenting right now that I thought had stopped early. I re-checked with a hydrometer and they both hit the target dead on.

I had no idea the refractometer would be that off. When I started a year ago, I was having all kinds of problems with fermentation. The first thing I did was to get a refractometer so I could take more readings using less beer. Since then I've been improving my process thinking I was doing something wrong. I'm sure I was at the beginning, but I didn't realize my measurements were off the entire time.

I guess there's a silver lining to all of this. My process is dead on. My efficiency and attenuation are both excellent.

Thanks to everyone here for all the help!
Click to expand...

If by genius you mean we all learned from making the same mistake, then yes, we are :D
 
Smokingman said:
It's in Brix so I assumed it would be correct.
Click to expand...

On the original post you converted the Brix to SG to post your message. I going to guess here that your original Brix reading was 25-26. Then your final reading was around 12-13 ? If those numbers are in the ballpark of what you saw, the correct final gravity would be 1.017 after conversion. What did you read with the hydrometer?
 

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