Stuck fermentation.... again....

[conspiccus]

Hello all,

I have a rye IPA in primary and was hoping to transfer to secondary tomorrow, but the SG is still way too high (1.034). OG was 1.058 almost 3 weeks ago.

For an 11L (2.4 gal) batch I mashed 3.6kg (7.9 lbs) Golden Promise pale malt at 68 degrees celsius with mashout to 75 degrees without sparge. I cold steeped 310g (0.68 lbs) roasted rye in 1.2L (0.32 gal) of water overnight and added that to the boil with 15 minutes left. I left the wort in the brew kettle until it was cool enough to pitch. I used 15g (0.5oz) safale US-05. OG was 1.058. After 11 days the SG was 1.034 and after 20 days it is still 1.034. I ferment in large plastic buckets in my living room so there is no temperature control but the weather has been between 20-30 degrees celsius the past few weeks (last few days were the hottest, so I think this mimicked warming the fermentation vessel).

Any idea where I went wrong or how I can fix this? I am hoping to get down to 1.009. This also happened to another brew I had that started at 1.055 and got stuck at 1.020, which I went ahead and bottled anyway (it was stuck here for a few weeks even after pitching more yeast). I build the recipes myself using brewfather, so it may be a recipe issue, but any advice would be great!

 

[Hoppy2bmerry]

How did you get your gravity reading?

 

[conspiccus]

How did you get your gravity reading?

I used a turkey baster to transfer out from the fermentation bucket into a 100ml cylinder. I then let the foam clear off and put in the hydrometer and gave it a good spin. I know it isn't good to open the fermentation bucket, but figured the 10 seconds it takes to transfer would be okay? I should also mention that I don't think my thermometer is accurate as it was reading that the sample was 5*C so I assumed the liquid temp was the same as room temp (between 20-25*C)

 

[Hoppy2bmerry]

Okay, yes the ordinary fermentor needs to be opened to get the sample. The possible problem with the reading is that The temp of the beer needs to match the calibration of the hydrometer or a calculation must be done to get the correct SG.
You May know that already, but it is a fairly common mistake that people make, including myself.

 

[MMX]

Difference in temperature to cal temp of the hydrometer would account for a couple points, not ~30 points. Tough to say why it's stuck - you mention the thermometer's accuracy, could your mash temp have been higher than the 68C you mentioned? If it was hotter, some accelerated denaturing of the enzymes may have happened (thus not converting more complex sugars into fermentable ones).

 

[conspiccus]

Difference in temperature to cal temp of the hydrometer would account for a couple points, not ~30 points. Tough to say why it's stuck - you mention the thermometer's accuracy, could your mash temp have been higher than the 68C you mentioned? If it was hotter, some accelerated denaturing of the enzymes may have happened (thus not converting more complex sugars into fermentable ones).

This is exactly what I was thinking might be the issue but of course there’s no way to know now. I’m planning a new brew this weekend so I’ll have to get a new thermometer and see, thanks for your input!

 

[dmtaylor]

could your mash temp have been higher than the 68C you mentioned? If it was hotter, some accelerated denaturing of the enzymes may have happened (thus not converting more complex sugars into fermentable ones).

^^^THIS.^^^ I wonder if you killed off the enzymes from mismeasurement or miscalibration of the mash thermometer.

And how was the mash pH?

 

[conspiccus]

Okay, yes the ordinary fermentor needs to be opened to get the sample. The possible problem with the reading is that The temp of the beer needs to match the calibration of the hydrometer or a calculation must be done to get the correct SG.
You May know that already, but it is a fairly common mistake that people make, including myself.

Yeah, I was thinking this would count for a slight difference in gravity reading but not 25 points surely?

 

[conspiccus]

^^^THIS.^^^ I wonder if you killed off the enzymes from mismeasurement or miscalibration of the mash thermometer.

And how was the mash pH?

mash pH came in at 5.47 on my brewfather calculator. I don't have a pH meter though, so that may be an issue as well. The thermometer I used was one that came with the Brooklyn Brewshop Everyday IPA brew kit that I got a few months ago. I contacted them and they informed me that it's an alcohol filled thermometer. I assumed the intrinsic property of the alcohol is what the reading is based off of, so not sure how that could be inaccurate?

 

[brewbama]

Put it in ice water and see what it reads. Put it in boiling water and see what it reads.

 

[conspiccus]

After looking at some other forums, it seems like 2 teaspoons of alpha amylase will help eat up the complex sugars and bring the gravity down. thoughts?

 

[MMX]

After looking at some other forums, it seems like 2 teaspoons of alpha amylase will help eat up the complex sugars and bring the gravity down. thoughts?

Should work well if our suspicions are correct, good luck!

On your earlier post - correct, it would not be a difference of 25 points...a few at most.

 

[dmtaylor]

Put it in ice water and see what it reads. Put it in boiling water and see what it reads.

And this.^^^

After looking at some other forums, it seems like 2 teaspoons of alpha amylase will help eat up the complex sugars and bring the gravity down. thoughts?

That should work.

 

[conspiccus]

UPDATE: I added the alpha amylase around 30 hours ago and just took another gravity reading. It is still 1.034. I got a thermapen thermometer so the temp is accurate now. I read elsewhere that the gravity would start to reduce in just 24 hours after AA addition, but nothing yet with my beer. I did however see some bubbles and foam on top of the beer when I opened the fermentation vessel. Any knowledge on the time it takes for alpha amylase to start working? Any other reasons why my gravity is still so high?

 

[MMX]

Alpha amalyse prefers a higher temperature than fermentation temperature for conversion. It will still happen, just takes longer (not sure how long however).

 

[Mtrhdltd]

Just out of curiosity why didn't you mash the rye? This might lessen your available fermentable sugars, but not 30 points. In my RyePA I mash all grains together. I believe the others have answered your question as a mash efficiency problem. I have never added enzymes myself, I'm of no help I guess.

 

[conspiccus]

Just out of curiosity why didn't you mash the rye? This might lessen your available fermentable sugars, but not 30 points. In my RyePA I mash all grains together. I believe the others have answered your question as a mash efficiency problem. I have never added enzymes myself, I'm of no help I guess.

Because it was roasted I figured all the fermentable sugars were cooked out and it was more of a flavour addition. I use BIAB in a buffalo boiler and made a porter the week before that scorched the hell out of the bottom of the brew kettle so I read that you could essentially get the flavour out of roasted grains without the mess of scorching by cold steeping them overnight.

 

[Mtrhdltd]

That all very well could be true, I don't know. I use rye malt, so totally different. How did you scorch your pot? Heat on with the bag in? Another curiosity, haven't scorched mine yet with biab, but only been brewing biab for about 9 months.

 

[conspiccus]

That all very well could be true, I don't know. I use rye malt, so totally different. How did you scorch your pot? Heat on with the bag in? Another curiosity, haven't scorched mine yet with biab, but only been brewing biab for about 9 months.

Well given the problem with this batch, I gather that the mash temp was too high but also I do keep the boiler on "keep warm" as opposed to turning it all the way off, do you reckon I should turn it all the way off? And with the darker grains I found they scorch much easier than pale malt. I've only been brewing for a handful of batches so I'm still very much a rookie. Any advice would be much appreciated!

 

[Mtrhdltd]

I use thinner kettles with propane burners, different than electric. I don't add any heat during my mash, I just wrap a couple of towels around my kettle and usually maintain temp just fine. I think your new thermometer will be your guide.

 

[dbsmith]

Your OG seems way off. I don't know anything about Golden Promise, but for 2.4 gallons, 7.9 lbs. of grain should have been closer to 1.08ish depending on your efficiency... I guess you did no sparge so your efficiency is on the lower end but that still just seems so low to me

Either your measurements are way off for some reason, or something in your process is seriously wrong in order to get such a whack OG/FG. I would first verify your measurements are correct by checking your hydrometer using water, as well as in solutions of malt extract to see if you get what you would expect. If your gravity measurements are correct, then you can narrow it down to process. Perhaps it is your thermometers, etc...

Also, did you mention your mash time and water to grain ratio?

Just thought of one other thing: did you do an iodine test? If you take a few drops of your beer + a drop of iodine, you should be able to tell if there are starches present. If there are (turns black), that would indicate you did not reach completion with your mash and there are still starches present which did not get broken down into simple sugars. It might be too late this time since you already added the amylase, but if it happens again then this might be worth doing to help investigate the cause.

 

[bracconiere]

UPDATE: I added the alpha amylase around 30 hours ago and just took another gravity reading. It is still 1.034. I got a thermapen thermometer so the temp is accurate now. I read elsewhere that the gravity would start to reduce in just 24 hours after AA addition, but nothing yet with my beer. I did however see some bubbles and foam on top of the beer when I opened the fermentation vessel. Any knowledge on the time it takes for alpha amylase to start working? Any other reasons why my gravity is still so high?

alphas not going to do anything for a ferment, if you want it dry it takes gluco...

 

[conspiccus]

Your OG seems way off. I don't know anything about Golden Promise, but for 2.4 gallons, 7.9 lbs. of grain should have been closer to 1.08ish depending on your efficiency... I guess you did no sparge so your efficiency is on the lower end but that still just seems so low to me

Either your measurements are way off for some reason, or something in your process is seriously wrong in order to get such a whack OG/FG. I would first verify your measurements are correct by checking your hydrometer using water, as well as in solutions of malt extract to see if you get what you would expect. If your gravity measurements are correct, then you can narrow it down to process. Perhaps it is your thermometers, etc...

Also, did you mention your mash time and water to grain ratio?

Just thought of one other thing: did you do an iodine test? If you take a few drops of your beer + a drop of iodine, you should be able to tell if there are starches present. If there are (turns black), that would indicate you did not reach completion with your mash and there are still starches present which did not get broken down into simple sugars. It might be too late this time since you already added the amylase, but if it happens again then this might be worth doing to help investigate the cause.

Just checked the hydrometer and all seems good on that front. I have never heard of the iodine test, that sounds like a great thing to have in the future so will get some of that for sure. My mash time was 60 minutes and the mash water was 22L (my boil off is 5L/hr and deadspace is 5L) so Brewfather actually calculated my OG to be 1.061 and I fell slightly short (probably due to the late roasted rye grain liquid addition)

 

[conspiccus]

alphas not going to do anything for a ferment, if you want it dry it takes gluco...

Thank you for bringing this up, I have been very confused on this because there seems to be a lot of conflicting info on this front. Some people have simply thrown it into the fermenter and had results but most places say to add it to the mash to heat it up before fermentation. Figured it couldn't hurt to throw some in and see what happens but do you think throwing in some gluco amylase on top of that will hurt in any way?

 

[IslandLizard]

Have you compared readings from your new Thermapen* with the old alcohol based thermometer? Especially at around 68°C.
That may shine some light on the actual mash temp you used, and thus on fermentability and the issue you're having.

* The Thermapen should be assumed accurate, but it won't hurt to double check in both melting ice (0°C) and boiling water (100°C).

 

[conspiccus]

Have you compared readings from your new Thermapen* with the old alcohol based thermometer? Especially at around 68°C.
That may shine some light on the actual mash temp you used, and thus on fermentability and the issue you're having.

* The Thermapen should be assumed accurate, but it won't hurt to double check in both melting ice (0°C) and boiling water (100°C).

Yeah I did and we were right the alcohol thermometer was way off compared to the thermapen. I actually brewed an IPA 6 days ago with the thermapen in my arsenal and the OG came to 1.066 and today it is already down to 1.016. This pretty much confirms the issue was in the mash temp being too high. Hopefully the alpha (and potentially gluco) amylase brings the RyePA down to proper FG but I think the problem is fixed for future brews! Can't wait to try this brew again with the thermapen and get a good fermentation and final product that I'm expecting. Will keep everyone updated!

 

[IslandLizard]

For an 11L (2.4 gal) batch I mashed 3.6kg (7.9 lbs) Golden Promise pale malt [...] OG was 1.058

That's very poor mash/brewhouse efficiency!
Most brewers can get a 4 (Imperial) gallon batch at that same gravity (1.058) from 8 pounds of Golden Promise. That may point to a coarse crush, and/or poor conversion in the mash.

 

[IslandLizard]

the alcohol thermometer was way off compared to the thermapen.

How much off was it?
Just out of curiosity, and having a data point.

 

[passedpawn]

Thank you for bringing this up, I have been very confused on this because there seems to be a lot of conflicting info on this front. Some people have simply thrown it into the fermenter and had results but most places say to add it to the mash to heat it up before fermentation. Figured it couldn't hurt to throw some in and see what happens but do you think throwing in some gluco amylase on top of that will hurt in any way?

When solving an attenuation problem, you can (and should) throw AA right into the fermentor. Bring the fermentor to room temperature. If the majority of the grains was barley, you should see a further drop in gravity. With AA, your 1.060 beer should end up at around 80% attenuation, or about 1.012.

But normally, there's no benefit to using AA in the mash because it's already in the barley. A proper mash doesn't require it, except in the case of making light lagers and such where maximum attenuation is desired. In that case, other enzymes like gluco can help a lot.

Alpha amylase enzymes is the SAME thing that's in the barley already. That's why we mill grain and mix it with water - to get the AA to meet the starchy sugars and reduce them to smaller sugars. Without this enzymatic conversion, the yeast would not be able to ferment the original large sugars.

Heating the mash greatly increases the enzyme's rate of conversion. Once milled and wet, the bacteria in the barley will begin to ruin it, so we want to get the sugar conversion done quickly, then move to the boil where we kill the souring bacteria. But TOO hot and the enzymes are permanently damaged (denatured). Too cool and the enzyme activity is low and perhaps won't fully convert. NOTE: given enough time, the enzymes would indeed do the conversion - even at room temperature.

 

[passedpawn]

alphas not going to do anything for a ferment, if you want it dry it takes gluco...

I don't think this brewer wants to "take it dry" - it's a 1.060 rye IPA and over-attenuation from gluco could very well make it undrinkable.

As I just typed above, AA is helpful in the fermentor if there was problems with the original mash - and that seems to be the case.

 

[conspiccus]

To be fair the alcohol thermometer may have been dropped a few times so the fault is probably down to the user

When solving an attenuation problem, you can (and should) throw AA right into the fermentor. Bring the fermentor to room temperature. If the majority of the grains was barley, you should see a further drop in gravity. With AA, your 1.060 beer should end up at around 80% attenuation, or about 1.012.

But normally, there's no benefit to using AA in the mash because it's already in the barley. A proper mash doesn't require it, except in the case of making light lagers and such where maximum attenuation is desired. In that case, other enzymes like gluco can help a lot.

Alpha amylase enzymes is the SAME thing that's in the barley already. That's why we mill grain and mix it with water - to get the AA to meet the starchy sugars and reduce them to smaller sugars. Without this enzymatic conversion, the yeast would not be able to ferment the original large sugars.

Heating the mash greatly increases the enzyme's rate of conversion. Once milled and wet, the bacteria in the barley will begin to ruin it, so we want to get the sugar conversion done quickly, then move to the boil where we kill the souring bacteria. But TOO hot and the enzymes are permanently damaged (denatured). Too cool and the enzyme activity is low and perhaps won't fully convert. NOTE: given enough time, the enzymes would indeed do the conversion - even at room temperature.

Thanks for that really clear explanation about AA! I think I will leave the RyePA in the fermenter with the AA for a few weeks at least to allow the gravity to come down. Do you have any info about the difference between AA and GA?

 

[passedpawn]

To be fair the alcohol thermometer may have been dropped a few times so the fault is probably down to the user

Thanks for that really clear explanation about AA! I think I will leave the RyePA in the fermenter with the AA for a few weeks at least to allow the gravity to come down. Do you have any info about the difference between AA and GA?

I've used gluco in light lagers myself. I think it shaved a few additional gravity points off the final beer. Like I said though, you don't want that in your IPA until you've exhausted better options.

If the gravity doesn't budge a week after the AA, you're going to want to do SOMETHING. In addition to the AA, dump a packet of dry yeast in there now. That should cover all the bases I'd think. I suppose if you try these things and you see no effect, gluco (and even the evil Beano) are options. Your beer has enough alcohol in it now to protect it from infection, so you have some time to experiment.

 

[IslandLizard]

dump a packet of dry yeast in there now.

I seriously doubt that will change anything:

I used 15g (0.5oz) safale US-05. OG was 1.058.

That's a pitch of more than 1 retail pouch (11.5g) in only 11 liters of 1.058 wort. That's more than plenty, unless the yeast was damaged.

Yeast is not the problem. But the OP may have mashed as high as 88C...

 

[conspiccus]

How much off was it?
Just out of curiosity, and having a data point.

When pulling the alcohol thermometer out of the case it reads 5*C and when I put it in room temp water it didn't even move. It only moved up once i ran hot tap water. When I brewed this last weekend thermapen showed 66*C mash and the alcohol thermometer showed 56*C so it was a difference of 10*C which obviously is pretty big.

Not dissing the alcohol thermometer, it may or may not have been dropped a few times in it's life, so probably more of a user fault

 

[IslandLizard]

When pulling the alcohol thermometer out of the case it reads 5*C and when I put it in room temp water it didn't even move. It only moved up once i ran hot tap water. When I brewed this last weekend thermapen showed 66*C mash and the alcohol thermometer showed 56*C so it was a difference of 10*C which obviously is pretty big.

Not dissing the alcohol thermometer, it may or may not have been dropped a few times in it's life, so probably more of a user fault

Some alcohol thermometers can be slow to respond and imprecise, those are intentionally built that way, averaging temps over a minute, or even a few minutes.

If yours was reading 10C under the Thermapen, you may well have mashed at 78C instead of your intended 68C. That might explain much of your unintended high FG right now.

If that's the case, your fermentation isn't "stalled," the yeast you pitched simply can't ferment any lower, it can't digest (metabolize) the higher sugars and other unfermentables (e.g., maltotriose and dextrins) in your beer, as it is. Having a good portion of unfermentables is good in a low gravity/low alcohol Mild, much less useful in a Pale Ale.

 

[passedpawn]

I seriously doubt that will change anything:

That's a pitch of more than 1 retail pouch (11.5g) in only 11 liters of 1.058 wort. That's more than plenty, unless the yeast was damaged.

Yeast is not the problem. But the OP may have mashed as high as 88C...

Last year I used liquid yeast in a lager - both pouches failed to ferment. They were both mostly dead (Wyeast pouches bloated, but just a little). So, it happens.

Anyway, more yeast can't hurt anything. I wouldn't hesitate to do it.

 

[IslandLizard]

Last year I used liquid yeast in a lager - both pouches failed to ferment. They were both mostly dead (Wyeast pouches bloated, but just a little). So, it happens.

Anyway, more yeast can't hurt anything. I wouldn't hesitate to do it.

That's different though, failing to ferment vs. fermenting down to a certain point, which is not failure.
The yeast she pitched proved she was healthy, and fermented as far as she could. It was also quite a royal pitch.

There's plenty of yeast in there after fermenting it down about 1/2 way. Hopefully the GlucoAmylase serves up some digestible sugars she can then ferment.

 

[bracconiere]

@conspiccus when i was making 100% rice beer, alpha goes into the mash...but if i didn't add gluco to the fermenter, i'd get attenuation like what you're describing....(gave me the runs something fierce, dextrins are soluble fiber)....alpha is a random chopper, and gluco is a fine detail worker....

in a mash, it's actually beta that is the fine detail worker, but it denatures pretty quick at high temps....that's why there's a "mash window", you need both the alpha and beta working....but as far as i know, no one sells beta amylase, so it's gluco, and it will finish at 1.000 (or less)


(making the rice beer is how i discovered gluco in the first place! a 20lb bag is cheap and i'd get a decent drink, with dry hopping, 10 gallons 7.5% ABV for one of these

https://www.walmart.com/ip/Great-Va...BS6FDZAYxtMo1tYbCTVIY_zCmwieGmh4aAtfMEALw_wcB
of course that's off-topic, sorry, but gluco will make it go to 1.000, and it will be like a Brüt IPA, low calorie for day drinking)


edit: just like proteins are balled up amino acid formed with the easy to form amide bond, starches are similar, think long chains of legos, alpha randomly chops them, and gluco makes sure to cut them small....

 

[conspiccus]

@conspiccus when i was making 100% rice beer, alpha goes into the mash...but if i didn't add gluco to the fermenter, i'd get attenuation like what you're describing....(gave me the runs something fierce, dextrins are soluble fiber)....alpha is a random chopper, and gluco is a fine detail worker....

in a mash, it's actually beta that is the fine detail worker, but it denatures pretty quick at high temps....that's why there's a "mash window", you need both the alpha and beta working....but as far as i know, no one sells beta amylase, so it's gluco, and it will finish at 1.000 (or less)


(making the rice beer is how i discovered gluco in the first place! a 20lb bag is cheap and i'd get a decent drink, with dry hopping, 10 gallons 7.5% ABV for one of these

https://www.walmart.com/ip/Great-Va...BS6FDZAYxtMo1tYbCTVIY_zCmwieGmh4aAtfMEALw_wcB
of course that's off-topic, sorry, but gluco will make it go to 1.000, and it will be like a Brüt IPA, low calorie for day drinking)


edit: just like proteins are balled up amino acid formed with the easy to form amide bond, starches are similar, think long chains of legos, alpha randomly chops them, and gluco makes sure to cut them small....

So the next question is how much to add? and how long does it normally take to bring the SG down?

 

[dmtaylor]

So the next question is how much to add? and how long does it normally take to bring the SG down?

My advice - use less than you think you need, and it takes much longer to ferment out than you think it should. We‘re talking like 1/8 teaspoon, and 4-6 weeks to complete the fermentation.If you keg, it doesn’t much matter, but if you bottle you could end up with gushers or bombs if you bottle too soon. Fermentation should pick up again but very slowly in my experience.