Incomplete fermentation?

[Pointer64]

Hello all. I've just started BIAB brewing and am having problem hitting my gravity readings - specifically the post fermentation gravity reading.

I am using Brewsmith and generally get the Post boil SG about right in accordance with the recipe brew notes. I use the no chill method in the cube. When I begin the fermentation process I don't bother taking another gravity reading (should I?) because I figure it should not have changed in the cube.

Typically I use 1 or 2 rehydrated Saale 05 sachets into the fermenter. Fermentation is temperature controlled at 19deg inside a fridge. Vigorous fermentation starts very quickly and all seems good at his stage.

FG after 15 days at 1.025. Again today (day 17) at 1.025 so fermentation has finished. Other brews have been had similar results.

Any ideas, suggestions or solutions gratefully accepted.

To much fun, love and attention goes into the brewing for me to be satisfied with low or mid strength beer.

Cheers

 

[mkstalen]

What temp are you mashing at?
Without going into specifics, the higher your mash temp, the more unfermentable sugars there will be.

Sent from my Samsung S3 using Tapatalk.

 

[Pointer64]

What temp are you mashing at?
Without going into specifics, the higher your mash temp, the more unfermentable sugars there will be.
Sent from my Samsung S3 using Tapatalk.

Just checked my notes re this brew - 60 minute mash at 68 deg. Temp dropped to 63 so burner back on and my notes say that it got a little hot toward the end of mash ie. 72 deg.

 

[TheWiggman]

Were you careful transferring the wort into the fermenter or did you let it splash around to buggery? If there's not much oxygen in there your fermentation will finish early.

ED: Have read up, dry yeasts need oxygen for the starter but not critical for the wort provided they have been rehydrated -
http://www.danstaryeast.com/articles/aeration-and-starter-versus-wort

Pretty scientificky, I imagine most commercial dry yeasts are the same.

 

[verysupple]

What sort of OG are we talking about here? For a typical ale of about OG 1.050 an FG of 1.025 seems a bit high to blame on mash temps, your thermometer would have to be out by roughly 10 C for it to finish that high.

Without more detail I'm inclined to think along the same lines as TheWiggman, make sure you're aerating well before pitching. It wouldn't be a bad idea to do a fast ferment test on the next batch. That's when you save a small sample and pitch lots of healthy yeast and keep it really warm (room temp is OK but 25 C is good). Give it a good shake every now and then to give it more oxygen and in a day or two it should have reached the true FG for that batch. It'll taste nasty from all the oxidation and high ferment temp but at least it'll tell you if the yeast are conking out early or if that really is as low as that wort with ferment.

 

[Steve]

Hello all. I've just started BIAB brewing and am having problem hitting my gravity readings - specifically the post fermentation gravity reading.

I am using Brewsmith and generally get the Post boil SG about right in accordance with the recipe brew notes. I use the no chill method in the cube. When I begin the fermentation process I don't bother taking another gravity reading (should I?) because I figure it should not have changed in the cube.

Typically I use 1 or 2 rehydrated Saale 05 sachets into the fermenter. Fermentation is temperature controlled at 19deg inside a fridge. Vigorous fermentation starts very quickly and all seems good at his stage.

FG after 15 days at 1.025. Again today (day 17) at 1.025 so fermentation has finished. Other brews have been had similar results.

Any ideas, suggestions or solutions gratefully accepted.

To much fun, love and attention goes into the brewing for me to be satisfied with low or mid strength beer.

Cheers

It is high after that amount of time. Id try upping the temp up to 22-25 and see if it kicks off again. If its still the same in another couple of days then its probably done. What did it start off at? If you're starting gravity is ok then its not your technique. You also don't need to use 2 sachets of US-05. Ones plenty. Its also not necessary to oxygenate your wort if using dry yeast. Just sprinkle it in and seal it up. How are you taking your readings? From the tap? Do you draw off one test tubes worth and discard (drink) that and then draw off another and use that to measure? The second tubes worth should be clearer of floaties and should give a different reading.

 

[NewtownClown]

Using a Hydrometer or a Refractometer?

 

[verysupple]

It is high after that amount of time. Id try upping the temp up to 22-25 and see if it kicks off again. If its still the same in another couple of days then its probably done. What did it start off at? If you're starting gravity is ok then its not your technique. You also don't need to use 2 sachets of US-05. Ones plenty. Its also not necessary to oxygenate your wort if using dry yeast. Just sprinkle it in and seal it up. How are you taking your readings? From the tap? Do you draw off one test tubes worth and discard (drink) that and then draw off another and use that to measure? The second tubes worth should be clearer of floaties and should give a different reading.

Well there certainly is a lot of bad info there.

1) 1 packet of dry yeast is not always enough, especially seeing as we still don't know what the OG is. Furthermore, 2 packs for 23 L of 1.050 wort is not even over pitching. So the OP's pitching rate is fine.

2) Just because the OG is OK doesn't mean the techniques are fine. You can have the same OG and have very different FGs due to wort makeup. This can lead to undesired results.

3) "Just sprinkle" is hotly debated, but the OP already rehydrates so unless he's doing it wrong he's doing the best thing for the yeast. Why would you tell someone to do the opposite of what the manufacturer recommends and what brewing science has unequivocally shown to be best practice?

The one good bit of info was that when using Fermentis dry yeast you don't need to oxygenate. I missed the part about using US-05 when I wrote my first post, so ignore the aerating bit.

 

[Pointer64]

Were you careful transferring the wort into the fermenter or did you let it splash around to buggery? If there's not much oxygen in there your fermentation will finish early.

ED: Have read up, dry yeasts need oxygen for the starter but not critical for the wort provided they have been rehydrated -
http://www.danstaryeast.com/articles/aeration-and-starter-versus-wort

Pretty scientificky, I imagine most commercial dry yeasts are the same.

Yep splashed it around plenty.

 

[Pointer64]

What sort of OG are we talking about here? For a typical ale of about OG 1.050 an FG of 1.025 seems a bit high to blame on mash temps, your thermometer would have to be out by roughly 10 C for it to finish that high.

Without more detail I'm inclined to think along the same lines as TheWiggman, make sure you're aerating well before pitching. It wouldn't be a bad idea to do a fast ferment test on the next batch. That's when you save a small sample and pitch lots of healthy yeast and keep it really warm (room temp is OK but 25 C is good). Give it a good shake every now and then to give it more oxygen and in a day or two it should have reached the true FG for that batch. It'll taste nasty from all the oxidation and high ferment temp but at least it'll tell you if the yeast are conking out early or if that really is as low as that wort with ferment.

OG was 1.053. Never heard of a fast ferment so thanks for that.

 

[Pointer64]

It is high after that amount of time. Id try upping the temp up to 22-25 and see if it kicks off again. If its still the same in another couple of days then its probably done. What did it start off at? If you're starting gravity is ok then its not your technique. You also don't need to use 2 sachets of US-05. Ones plenty. Its also not necessary to oxygenate your wort if using dry yeast. Just sprinkle it in and seal it up. How are you taking your readings? From the tap? Do you draw off one test tubes worth and discard (drink) that and then draw off another and use that to measure? The second tubes worth should be clearer of floaties and should give a different reading.

Unfortunately I don't have the opportunity to kick it off again. I needed to keg it so I had beer on tap for my 50th birthday this weekend. OG was 1.053. I have used the sprinkle method but prefer to rehydrate as I have generally had more success with this method. Readings are with a fractometer. The reading on day 15 was first draw and yes there was plenty of floaties. The second reading on day 17 (kegging day) was taken part way through the gravity feed into the keg - the reading was the same.

 

[Pointer64]

Using a Hydrometer or a Refractometer?

Refractometer

 

[Pointer64]

Well there certainly is a lot of bad info there.

1) 1 packet of dry yeast is not always enough, especially seeing as we still don't know what the OG is. Furthermore, 2 packs for 23 L of 1.050 wort is not even over pitching. So the OP's pitching rate is fine.

2) Just because the OG is OK doesn't mean the techniques are fine. You can have the same OG and have very different FGs due to wort makeup. This can lead to undesired results.

3) "Just sprinkle" is hotly debated, but the OP already rehydrates so unless he's doing it wrong he's doing the best thing for the yeast. Why would you tell someone to do the opposite of what the manufacturer recommends and what brewing science has unequivocally shown to be best practice?

The one good bit of info was that when using Fermentis dry yeast you don't need to oxygenate. I missed the part about using US-05 when I wrote my first post, so ignore the aerating bit.

Yeah I don't use dry yeast - I always rehydrate as I have had better results previously. Re your point 2, what issues effect the wort makeup that may be causing this problem? And it seems to be happening most brews. Cheers

 

[verysupple]

I don't know how much experience you have so this might be a silly idea, but do you correct your refractometer readings for the alcohol content?

What are the FG readings in Brix?

 

[verysupple]

I did a quick google search for "refractometer alcohol correction" and found that if the OG was 1.053 and the uncorrected FG was 1.025, then the corrected FG would be more like 1.012 which sounds reasonable. Maybe this is the answer?

 

[verysupple]

Yeah I don't use dry yeast - I always rehydrate as I have had better results previously. Re your point 2, what issues effect the wort makeup that may be causing this problem? And it seems to be happening most brews. Cheers

All I really meant was that things like missing the mash temp will have an affect on the FG but not on the OG. So hitting your OG doesn't necessarily mean your process was fine. I don't think there is anything wrong woth your wort production, though. As I said earlier, if it was something like mash temp you'd have to be off by about 10 C. There maybe something amiss on the cold side, but at the moment I'm leaning toward not correcting the refractometer reading.

 

[NewtownClown]

Refractometer

There you go... the presence of alcohol is screwing up the reading. Google how to use a refractometer and you will find online calculators to assist in making the necessary corrections

All I really meant was that things like missing the mash temp will have an affect on the FG but not on the OG. So hitting your OG doesn't necessarily mean your process was fine. I don't think there is anything wrong woth your wort production, though. As I said earlier, if it was something like mash temp you'd have to be off by about 10 C. There maybe something amiss on the cold side, but at the moment I'm leaning toward not correcting the refractometer reading.

Of course mash temp will have an effect on OG.

 

[Pointer64]

I did a quick google search for "refractometer alcohol correction" and found that if the OG was 1.053 and the uncorrected FG was 1.025, then the corrected FG would be more like 1.012 which sounds reasonable. Maybe this is the answer?

I wasn't aware of the need for alcohol correction when using a refractometer so that may be the answer. As per your comment, 1.012 sounds about right. Thanks for that info. Very helpful.

 

[Pointer64]

There you go... the presence of alcohol is screwing up the reading. Google how to use a refractometer and you will find online calculators to assist in making the necessary corrections



Of course mash temp will have an effect on OG.

 

[Pointer64]

Ok so it seems my refractometer skills & knowledge are lacking. I'll do some further calls. Thanks to everyone who contributed ..... I really appreciate it. I'm still learning and I know the more I learn the better beer I will brew. Happy days