Stuck fermentation on an imperial stout

[dwick]

I brewed an imperial stout from an extract clone recipe that had an OG of 1.120 I used two packs of dry Safale US-05 and made a 1 liter yeast starter 24 hours in advance of pitching. After 4 weeks the SG had only gone down to 1.036 My LHBS advised pitching Imperial Yeast Ale Darkness A10 straight into the existing fermentation vessel. After 2 weeks, SG dropped very slightly to 1.034 All fermentation has been temperature controlled at 70 degrees. I think I should have made a larger (2 liter) yeast starter, and also let it grow for at least 2 days, but that's for the future.

What is the best course of action for this batch?

1.) Should I just accept an FG of 1.034 and move this to secondary and add the oak chips and bourbon?

2.) Will there be enough yeast to bottle-carbonate this?

3.) Should I add priming sugar before bottling, or is there enough sugar remaining already?

4.) Am I at risk for bottle bombs, especially if I bottle condition for a couple of weeks at 70 degrees?

 

[G_robertus]

I would've made a 2L starter or pitched 4/5 sachets. However, 1.036-1.034 is done. Depending on your exact recipe this beer has attenuated more than I would've expected in the first place. 70% AA on a stout this big is quite a lot already actually. Some of my recipes barely get to 65% even when adding sugar. Roasted grains are very poorly fermentable. Crystal malts also become less fermentable with increasing colour. This will drive attenuation down, so you're probably right where you should be.

Regarding the questions:
1. Yes. See above. Secondary is only needed if you're planning on ageing for several months, a few weeks won't hurt in primary.
2. After ageing I highly doubt it. Either add fresh US-05 or bottling yeast. This should also help calm your fears of bombs.
3. Definitely add sugar.
4. Most likely not. If you're very paranoid use killer-positive yeast so you won't get over-attenuation. But like I said, I think it's done.

Lower attenuation and high residual sweetness is exactly why I design my super big stouts I bitter to extremely high levels and use 10-15% roast to counter the sweetness. These three things also make the beer great for ageing.

Edit: I missed the part on extract, but extracts can also be poorly fermentable. Assuming you steeped various grains those too will not be very fermentable, so this is again to be expected.

 

[dwick]

G_robertus, thanks for the feedback. I guess I'll add the oak chips and bourbon now, skip racking to secondary, and in a week or two bottle the batch.

I have never added yeast at the bottling stage before, but I don't usually make such high ABV beers.

Should I rehydrate and pitch the US-05 when racking to my bottling vessel? Or do you recommend making a starter for it? If the Brewer's Friend calculator is correct, my beer should be at 11.29% ABV. (1.120 - 1.034) Will US-05 tolerate this level of alcohol?

 

[mac_1103]

You're over 11% ABV already. I would add priming sugar and wine yeast to bottle condition, the advantages being both higher alcohol tolerance and inability to ferment anything other than simple sugars. It will also kill any remaining US-05 so there is virtually zero risk of bottle bombs.

 

[dwick]

Thanks for the feedback. Would something like Lalvin EC-1118 work?

 

[mac_1103]

Would something like Lalvin EC-1118 work?

Absolutely. They sell CBC-1 specifically for bottle conditioning, but EC-1118 works just as well and costs a lot less.

 

[Luxy]

Hi all,

I have some question regarding secondary (bottle carb) as well. I brewed RIS according to https://brewersbestkits.com/assets/1046_russianimperialstout_recipe.pdf
The only difference is I used Kveik ale yeast that ferment at higher temperature.
The OG is 1.066 and FG is around 1.028~1.030 with slightly under 5% ABV. It is dump on a yeast cake of another batch of beer on the same bottling day of the previous batch.

The beer fermented for 4 weeks in the fermenter and taste ok when I took a FG reading. I dont mind the lower ABV so went to to bottle them with priming sugar added.

My questions are:
1. The FG did not reach the one specified in the recipe but it has already been in the fermenter for 4 weeks, there is no sign of infection nor does the beer taste very much off. Is it consider a stalled fermentation? If so would it still carb up after bottling them with priming sugar?

2. For my past experiences I always see small bubbling that trickle slowly up the headspace in the bottle. Does it always has to be this way or carb process may not necessary occur with small bubble trickling up the head space in the bottle? Bottle condition as per the instruction says carbonation may vary according to different condition and beer style sometimes may take weeks to carb up.

3. If bubbling is a must for carbonation process in the bottle, what to do if the batch I bottled does not carb (like the PET bottle are still pressable by hand and not pressurized) by the end of the supposedly carbonation period?

While still on the topic of carbonation in bottle,

4. If one somehow forgotten to add priming sugar in one bottle( I noticed one of the bottle again does not have bubbles trickling upward somehow making me suspecting that I might have forgotten to add sugar to that bottle.) Is there any remedy to it? Perhaps paying attention when opening it to prep sanitary steps in case it really does not carb up then quickly sanitize the cap area before opening it to add sugar and closing it back on(swing cap arrangements) and wait out another 2 weeks for it to carb?

Many thanks in advance!

 

[mac_1103]

I brewed RIS according to https://brewersbestkits.com/assets/1046_russianimperialstout_recipe.pdf

Did you use that kit or did you try to replicate it by buying the ingredients separately? You missed the OG by quite a bit and without knowing how or why that happened it's hard to know what FG you should have expected. But a FG that high with an OG that low doesn't sound good for any number of reasons.

I always see small bubbling that trickle slowly up the headspace in the bottle. Does it always has to be this way

I don't think I've ever seen bubbles in bottles while they were conditioning, but that's probably mostly because I haven't looked very often.

what to do if the batch I bottled does not carb (like the PET bottle are still pressable by hand and not pressurized) by the end of the supposedly carbonation period?

Maybe try one before you do anything else? You mentioned swing caps later so I assume the PET is just a test bottle?

I have successfully "recarbonated" under-carbonated beers by mixing up a priming solution, boiling it, letting it cool and then uncapping each bottle, adding a small volume of the solution with a syringe and recapping. You need to subjectively judge just how much more carbonation is needed so you can calculate how much priming sugar to use. Of course, this won't help if the problem is that the yeast are dead. In that case you would need to add a bottling yeast.

 

[G_robertus]

My questions are:
1. The FG did not reach the one specified in the recipe but it has already been in the fermenter for 4 weeks, there is no sign of infection nor does the beer taste very much off. Is it consider a stalled fermentation? If so would it still carb up after bottling them with priming sugar?

The recipe shows an extract recipe. Did you brew an extract version with the mentioned ingredients? If so, I think you might have an error in your OG measurement. It could be that the wort wasn't mixed well because missing your OG by that much in an extract recipe is very strange. If you followed the exact recipe and your OG is actually a lot higher, your FG might be correct. Extract, roast malt, caramel malt and maltodextrin can be or are poorly fermentable. The latter doesn't ferment at all. So 1.017 seems very low and anything near 1.025 could be correct.

2. For my past experiences I always see small bubbling that trickle slowly up the headspace in the bottle. Does it always has to be this way or carb process may not necessary occur with small bubble trickling up the head space in the bottle? Bottle condition as per the instruction says carbonation may vary according to different condition and beer style sometimes may take weeks to carb up.

Big beers can take a long time, but this isn't that big. You'd expect some carbonation by now.

3. If bubbling is a must for carbonation process in the bottle, what to do if the batch I bottled does not carb (like the PET bottle are still pressable by hand and not pressurized) by the end of the supposedly carbonation period?

While still on the topic of carbonation in bottle,

Warm it up, wait a bit longer or add bottling yeast. And yes you could still add sugar. However I'd try adding yeast to one bottle first, see if that does anything and if it doesn't add yeast and sugar.

 

[Luxy]

Did you use that kit or did you try to replicate it by buying the ingredients separately? You missed the OG by quite a bit and without knowing how or why that happened it's hard to know what FG you should have expected. But a FG that high with an OG that low doesn't sound good for any number of reasons.

I honestly do not know what happened to the gravity. But there is a incident happened during the transfer of the wort from the kettle to the fermenter that might induce contamination to the wort. I was pouring the wort into a vessel with a spigot with a filter bag in it so the wort goes through a filter before going into the fermenter. But in the midst of it the filter bag choke and got stuck in the vessel. I had to pull it out spilling the wort and some of the spill gets into the fermenter. I also had to squeeze the filter bag with bare hands to get whatever stuck inside out into the fermenter so the wort is kinda flowing over my hands before going into the fermenter. But on tasting the beer on the bottling day I did not notice anything off unless the reason I don't think they are off is due to inexperience.

The recipe shows an extract recipe. Did you brew an extract version with the mentioned ingredients? If so, I think you might have an error in your OG measurement. It could be that the wort wasn't mixed well because missing your OG by that much in an extract recipe is very strange. If you followed the exact recipe and your OG is actually a lot higher, your FG might be correct. Extract, roast malt, caramel malt and maltodextrin can be or are poorly fermentable. The latter doesn't ferment at all. So 1.017 seems very low and anything near 1.025 could be correct.

The only changes I did to the recipe were I used all DME instead of part LME part DME. I took 80% of LME's weight and added them to DME since all I have was DME. And replaced black barley with roasted barley. The amount of all the ingredients were average down accordingly to whatever DME I have at hand (it could be a messed up the the averaging math ... possibly)

I don't think I've ever seen bubbles in bottles while they were conditioning, but that's probably mostly because I haven't looked very often.

I am always excited during brew days and bottling days so I tend to go check them out frequently after pitching yeast. Bubbling air-locks and bubbles trickling up headspace in the bottle excites me. I am also anxious if I think I might have mess up in the process somewhere just like the choke filter incident happened for this stout brew so I would check them out frequently.

Maybe try one before you do anything else? You mentioned swing caps later so I assume the PET is just a test bottle?

I tend to bottle the beer with mixes of PET and swing cap bottles. This way if the PET pressurized up then there is a good chance those in swing caps glass bottle would do so as well unless I messed up with cleaning the glass bottles.

Big beers can take a long time, but this isn't that big. You'd expect some carbonation by now.

By carbonation you mean trickling of little bubbles up the headspace in the bottle right?

Warm it up, wait a bit longer or add bottling yeast. And yes you could still add sugar. However I'd try adding yeast to one bottle first, see if that does anything and if it doesn't add yeast and sugar.

I did another bottling yesterday on a batch that has used fresh new packet of yeast and took a chance to drop some yeast from the yeast cake into one of the stout bottle. So fingers crossed to see what happens in the next few days.

Thanks for the replies @mac_1103 & @G_robertus

 

[madscientist451]

Your final gravity is too high, I’m thinking it’s not going to be all that pleasant to drink. Sorry if this has been asked and I missed it, but is there any chance you are using a refractometer and not getting an accurate reading? If it’s accurate, I’d brew a dry stout and add Amalyse enzyme so the FG was very low and when it’s done, blend with your imperial stout. Or you could bottle what you have, brew a super low gravity stout, bottle that and then “blend in the glass” when you drink it.
How does it taste now?

 

[HM-2]

IMO this isn't a "stuck fermentation", it's done. You're at circa 13% ABV with an apparent attenuation of 70%, which is pretty much exactly where I'd expect an extract based beer with- presumably- a lot of crystal and (especially husked) roasted malt in it.

Most commercial imperial stouts, especially those barrel aged, are around 1.030-1.040FG. You need that extra FG to offset the bitter astringency you get from the quantity of roasted malt that goes into them.

 

[mac_1103]

I took 80% of LME's weight and added them to DME since all I have was DME.

This is why your OG was low. You adjusted in the wrong direction. The recipe calls for 6.6 lbs of Briess Traditonal Dark LME, which has 231 points. 5.3 lbs of DME only has 186 points. So that will lower the gravity of a five gallon batch by 9 points. Your final gravity still should have been about what the kit instructions say (edit - maybe two or three points lower depending on the yeast).

 

[mac_1103]

You're at circa 13% ABV with an apparent attenuation of 70%,

Who is? The thread has been hijacked. We're not talking about the OP anymore.

 

[HM-2]

Who is? The thread has been hijacked. We're not talking about the OP anymore.

Clearly missed the hijack. As you were.

 

[G_robertus]

The only changes I did to the recipe were I used all DME instead of part LME part DME. I took 80% of LME's weight and added them to DME since all I have was DME. And replaced black barley with roasted barley. The amount of all the ingredients were average down accordingly to whatever DME I have at hand (it could be a messed up the the averaging math ... possibly)

I tend to bottle the beer with mixes of PET and swing cap bottles. This way if the PET pressurized up then there is a good chance those in swing caps glass bottle would do so as well unless I messed up with cleaning the glass bottles.


By carbonation you mean trickling of little bubbles up the headspace in the bottle right?

Well the substitution explains the gravity. I think your trickling is what I mean with carbonation, the fizz and bubbles when opening a bottle and pouring it. Like a regular beer with foam and bubbles. I wouldn't worry about infection for now. Whilst it isn't ideal, you'll know when it is off and you can't really do anything unfortunately.

 

[Luxy]

@G_robertus
You're right! Carbonation process started right after my last reply to this thread As of now most of the bottles have sign of carb except for one which is too dark a glass to see clearly at least not until it has accumulate a good amount of foam like the one in the video These bubbles are so fine looks like a spec of of dust floating up slooooooooowly

Your final gravity is too high, I’m thinking it’s not going to be all that pleasant to drink. Sorry if this has been asked and I missed it, but is there any chance you are using a refractometer and not getting an accurate reading? If it’s accurate, I’d brew a dry stout and add Amalyse enzyme so the FG was very low and when it’s done, blend with your imperial stout. Or you could bottle what you have, brew a super low gravity stout, bottle that and then “blend in the glass” when you drink it.
How does it taste now?

I am using a normal hydrometer. There could be parallax error of +-2 I think. I am brewing at 31 degree Celsius room temp with Kveik. Dun think I can get Amalyse enzyme here where I am at. Anyway thanks for the advice.

This is why your OG was low. You adjusted in the wrong direction. The recipe calls for 6.6 lbs of Briess Traditonal Dark LME, which has 231 points. 5.3 lbs of DME only has 186 points. So that will lower the gravity of a five gallon batch by 9 points. Your final gravity still should have been about what the kit instructions say (edit - maybe two or three points lower depending on the yeast).

Oh, I am brewing on a smaller scale not the full scale of the recipe since I have only 1.2kg of Dark DME. I uses 80% of the LME's weight as I thought converting LME to DME is that LME is 20% water. Saw this info somewhere but could be my own misunderstood of the info as well. All in all I bottled about 6.3 liters from the fermenter I guess its about a 7liter brew.

But all seems well now since all except for one of the bottle has started carbonation already.

Thanks all for the helps given

 

[gaviga]

FYI, never use a high-gravity wine yeast for bottling unless you want bottle bombs! It'll dry your beer out and cause gushers. Use a bottling yeast like CBC-1. It only ferments bottling sugar so that you can control your carbonation. When I bottle my RISs, I just prime with corn sugar and let the residual yeast do the job, even when its 12%. I use 05 or Nottingham for my RISs.

 

[mac_1103]

I uses 80% of the LME's weight as I thought converting LME to DME is that LME is 20% water. Saw this info somewhere but could be my own misunderstood of the info as well.

You can make things a lot easier when converting and adjusting recipes by using an online calculator.

never use a high-gravity wine yeast for bottling unless you want bottle bombs! It'll dry your beer out and cause gushers. Use a bottling yeast like CBC-1. It only ferments bottling sugar so that you can control your carbonation.

CBC1 basically is a high gravity wine yeast. I think there is only one commercially available wine yeast that will ferment anything other than simple sugars. EC-1118 works just fine with no bottle bomb risk (unless you over-prime of course).

 

[gaviga]

You can make things a lot easier when converting and adjusting recipes by using an online calculator.


CBC1 basically is a high gravity wine yeast. I think there is only one commercially available wine yeast that will ferment anything other than simple sugars. EC-1118 works just fine with no bottle bomb risk (unless you over-prime of course).

CBC is not a wine yeast. It does not ferment maltose, thus it is used for bottling hg beers with residual fermentable maltose.

 

[mac_1103]

It does not ferment maltose.

EC-1118 does not ferment maltose either. The inability to ferment maltose is the primary difference between most beer yeasts and most wine yeasts. Show me any wine yeast that ferments maltose. Like I said, I'm pretty sure you will only find one.

 

[gaviga]

EC-1118 does not ferment maltose either. The inability to ferment maltose is the primary difference between most beer yeasts and most wine yeasts. Show me any wine yeast that ferments maltose. Like I said, I'm pretty sure you will only find one.

Interesting. I had thought differently.

 

[G_robertus]

Interesting. I had thought differently.

There are just a few wine yeasts that can ferment wort properly. K1V is the only one that comes to mind right now that will, but EC-1118 and other common wine yeasts will not.