Stuck fermentation help

[Winterfelch]

Hey everyone,

Newer brewer here. I have done about 5 brews (Just extract for now). I am starting to get a little bit frustrated however. Every single brew aside from my first attempt has resulted in a stuck fermentation. I have no idea why. I am using re-hydrated dry yeast. Both yeast and wort are roughly 70F at the time I pitch. Just went out to check on my latest batch and it is stuck at 1.030 (Started at 1.064 roughly)!! I have it hooked up to a temperature controller and the temperature remains stable. Any idea what could be causing these failures. More importantly, is there any way to restart the fermentation short of pitching more yeast? Thanks

 

[RM-MN]

Two questions:
1. Are you using a hydrometer or refractometer to take the FG reading?
2. What temperature are you fermenting the beer?

 

[Rob2010SS]

So you say it's stuck, but for how long has it been at 1.030? How many times have you checked it and gotten the same reading? I don't think it's an issue with your rehydration process as you've moved 30+ points so far but what kind of water are you using to rehydrate? What's your process there?

 

[Pappers_]

Its common for extract beers to finish a little higher, but you're right to be concerned about 1.030 - that's too high. It could be a measuring or temp issue, as RM suggested above. It could be that you have a lot of non-fermentables in your wort - what was your recipe and process?

 

[Rob2010SS]

Its common for extract beers to finish a little higher, but you're right to be concerned about 1.030 - that's too high. It could be a measuring or temp issue, as RM suggested above. It could be that you have a lot of non-fermentables in your wort - what was your recipe and process?

Why do you say extract brews finish higher? The 3 brews I have under my belt were all extract and none of them finished higher that I would have expected. 1.065-1.012, 1.051-1.010, & 1.041-1.008 respectively...

 

[Pappers_]

Why do you say extract brews finish higher? The 3 brews I have under my belt were all extract and none of them finished higher that I would have expected. 1.065-1.012, 1.051-1.010, & 1.041-1.008 respectively...

Depending on the extract you use, the malt used and the process used to make the extract, it may have a higher amount of non-fermentables. As a brewer, we can't control that aspect in the way we can if we chose the grain bill and do the mash ourselves.

Not all extract beers finish high, of course.

 

[Winterfelch]

Two questions:
1. Are you using a hydrometer or refractometer to take the FG reading?
2. What temperature are you fermenting the beer?

Hi there,

1. I am using a refractometer to take the FG reading. Just checked it again today and it hasn't budged.
2. I have it set up to ferment at 68 degrees Fahrenheit. According to the controller/thermowell it doesn't move more than a degree or two in either direction

 

[Winterfelch]

So you say it's stuck, but for how long has it been at 1.030? How many times have you checked it and gotten the same reading? I don't think it's an issue with your rehydration process as you've moved 30+ points so far but what kind of water are you using to rehydrate? What's your process there?

Hi,

Well I just checked again today and it hasn't budged. I just used tap water to rehydrate. Could that be the problem? My first batch met it's final gravity with just tap water and rehydrated yeast no problem.

 

[Winterfelch]

Its common for extract beers to finish a little higher, but you're right to be concerned about 1.030 - that's too high. It could be a measuring or temp issue, as RM suggested above. It could be that you have a lot of non-fermentables in your wort - what was your recipe and process?

Hey there,

Recipe was 7lbs LME, Roughly 1 Lb DME, and 1 Lb Corn Sugar. Recipe states FG should be around 1.014. I steeped some 40L to as a specialty malt but not much. Temp stays around 68F and doesn't move more than a degree or two in either direction. Third or fourth brew I have had that has just stopped like this so something HAS to be going on.

 

[Btaz]

Hi there,

1. I am using a refractometer to take the FG reading. Just checked it again today and it hasn't budged.
2. I have it set up to ferment at 68 degrees Fahrenheit. According to the controller/thermowell it doesn't move more than a degree or two in either direction

You need to use a hydrometer once fermentation starts. There are ways to use a refractometer, but I sit recommend it.

 

[ceb12]

Did you aerate it? I haven't moved to oxygen, but I shake/roll it. I have seen differences based on how good I am at that. Seems almost like yeast were not strong enough to finish the job based on what you are saying.

 

[Winterfelch]

Sorry it took so long for me to respond. Just started a new job on Monday so I have been swamped. I looked at the recipe and it looks like I underpitched by .5 grams. Is that enough to stop it so short of its listed FG though? Recipe called for 12 grams and I pitch 11.5 because thats how much came in a single packet. Should I just rehydrate and toss another 11.5 in this weekend? Still seems like it shouldn't have stopped quite so high simply because I was under by .5 grams.

 

[Jimbodaman]

USE a hydrometer not a refractometer to measure after fermentation takes place the alcohol distorts the light going through giving you an off reading. THere are calculators to help correct but aren't perfect especially if the beer is either high OG or low FG.

 

[Winterfelch]

USE a hydrometer not a refractometer to measure after fermentation takes place the alcohol distorts the light going through giving you an off reading. THere are calculators to help correct but aren't perfect especially if the beer is either high OG or low FG.

Will do, but do you think that the difference between those two could really skew the reading by .019 points?

 

[Winterfelch]

Did you aerate it? I haven't moved to oxygen, but I shake/roll it. I have seen differences based on how good I am at that. Seems almost like yeast were not strong enough to finish the job based on what you are saying.

Yep aerated it for about 5 minutes (shaking/rolling) before pitching.

 

[Winterfelch]

Thanks everyone. I had no idea not to use the refractometer for the FG reading. Found an online calculator to give me a rough correction and looks like I'm likely sitting in around 6% ABV. I just got learned...

 

[RM-MN]

Refractometers are a wonderful tool, especially with all grain brewing as you can take a sample of hot wort and get a reading in seconds without needing to cool it and it only takes a drop or 2 so you don't feel like you are wasting beer if you feel like taking multiple samples of the preboil wort to check on your mash efficiency but once alcohol is involved as in your nearly finished beer, the reading is skewed and needs a correction factor to get an approximately true reading. If you don't care if your FG is completely accurate, use the correction calculator and then use the fact that the reading isn't changing to prove that the fermentation is done. For complete accuracy in your finished beer you must use a hydrometer as the calculations may not be as accurate as you might think.

 

[Pappers_]

You need to use a hydrometer once fermentation starts. There are ways to use a refractometer, but I sit recommend it.

Buy or borrow a hydrometer and see if its measuring the same as the refractometer.