Stalled RIS- Suggestions

[Ben1]

Hey guys

Brewed my first Russian Imperial Stout a couple of weeks ago. Recipe was from Brewing Classic Styles (Czar's revenge).

I underestimated my efficiency and overshot my OG. Ended up at 1.105 (aiming for 1.098)

I cubed it so my oxygenating consisted of me tipping from height into the fermentor. I suspect this may not have been enough.

I rehydrated 2 x 12gm US 05 and dumped in (this also may have been a bit under what i needed).

My fermentation has stalled at 1.038 (with a Beersmith estimated OG of 1.026).

I fermented at 19 degrees and once it stalled, I increased the temperature and stirred up the yeast cake. It is now sitting at 22 degrees with no action.

Seeking suggestions on next steps:

1. get another pack of US05, rehydrate and dump in;
2. get a champagne yeast and try that;
3. Give up and keg (I fear bottling anything straight from the fermentor for fear of bottle bombs); or
4. other?

 

[razz]

Hey Ben. What was the volume in the fermenter? Given that US05 can typically go to 80% attenuation you are not far off your target. If you already have a packet of yeast then pitch it.
I can't comment on the champagne yeast as I haven't used it, you would need to check that it won't pull your gravity down close to 1.000. I would wait a few weeks and see if the gravity gets to target.
Keep us informed what happens as we can all learn from this, and I'll go and have a read of the book.

 

[Ben1]

Thanks Razz. Volume is 21.5L.

 

[manticle]

Definitely underpitched and under oxygenated but don't forget alcohol tolerance too.
I would look at 3 fast ferment tests.
1. Sample, heat and shake only.
2. Sample, active starter us05, heat and shake.
3. Sample, active starter of high abv tolerant beer yeast like wy1388, heat and shake.

Test gravity on all three, see which one works. If none do, she's very likely done.

 

[Mardoo]

Hold off on the champagne yeast. You could pitch an active starter of White Labs 099 Suoer High Grav. It's slow but it'll get the job done and leave behind better flavour than the champagne yeast. It's what I used to finish off from a 1.044 stall, and it ended at 1.026 IIRC. I'll be using it again on my next RIS ferment. You could also go with an active starter of the Trappist High Grav, but it may add a touch of Belgian character.

I'm not a US05 user but any pitch into that high an alcohol content will lose at least half the yeast, so pitch a lot if you go that route.

 

[manticle]

Yeah I'd not go for wine/champagne yeast.

Active starter of whatever you do add is a must though.

 

[Ben1]

Thanks guys. I don't have any yeast around so if I'm going to buy some, I might as well use it I guess rather than do the ferment tests. I'll get some wy1388 (seems to be what CraftBrewer have) and do a small starter (1L?)

Hopefully that will see some action!

 

[manticle]

You can do the ferment tests at the same time. Only need a hydrometer tube worth for each. You spent how much time and money already on this brew?

 

[Ben1]

Hey manticle, so your thoughts are that I should do them at the same time? Is the idea to use the majority of the yeast for the starter and some on the ferment test? What is the benefit? If the ferment test shows there is room to move but the starter still doesn't budge it, wouldn't I be in the same position?

My apologies if this is obvious and I'm must missing it

 

[manticle]

You only need a small amount of yeast with the ff test. What it does is show you the potential. You keep them warmer than you would the main brew and agitate the bejesus out of them (equivalent would oxidise the main brew). If they don't shift, you can be confident the brew is done. With yeast straight in the main brew, you probably won't be.
Peace of mind as much as anything else.

 

[Black n Tan]

I think it is likely done even though you under-oxygenated and under-pitched. I had a look at Classic Styles and expected AA is 64%, which is what you have hit. I would not take too much notice of what Beersmith says is an expected FG as there are too many factors to be considered. A fast ferment test will let you know for sure however. You could pitch an active starter to see if it goes lower as others have suggested. However I disagree with concern that champagne yeast will drive the gravity down to 1.000 or some such. That is simply not true and I find most people that advise against the use of champagne yeast have never tried it. Their concern is that because champagne is so dry the same will happen to beer. However champagne yeast can only consume simple sugars (for which grape juice is full of), but these are also the first sugars to be consumed by beer yeast and the remaining sugars are too complex to be consumed by champagne yeast: the most complex sugar champagne yeast can metabolise is maltose IIRCC. In your case you could add the champagne yeast a couple of days before bottling to be safe.

 

[Ben1]

Thanks guys. @blackntan you are right- I looked at the recipe and I have hit the gravity spot on. I'll do a ferment test as per manticles suggestions and report back

You guys are champs as always

 

[manticle]

I don't believe it will hit 1.000 with champagne yeast - just that wine type yeast can affect flavour in a less than favourable way (based on my admittedly limited personal experience with trying the same).

Think Mardoo was getting at the same.

 

[HBHB]

Ben, back to basics first.....hydrometer test or refractometer test of the sample?

Refractometers throw errors in fermented beers and readings need to be adjusted for the alcohol content.

Are the thermometer/s you used in the mash calibrated - question is, was your mash at the right temp to enable yeast to chew it out to the expected FG. Ie, if you were measuring , say 68 degrees, was it at that temp or was your mash temp actually higher?

A cheaper option if it is indeed stuck would be a packet of rehydrated CBC1 yeast. It'll go into a beer with abv which is toxic to many other yeasts and chew it down to where it needs to be.

Sorry for all the questions, but it's pointless to give instructions unless we know what's caused fermentation to stop.

 

[Ben1]

@hbhb using hydrometer and am confident in it's measurements.

Thermometers seem to be fine. Mash was at 68 degrees for one hour. After the hour recorded temp was 65 which is my normal temp loss in my mash tun.

 

[Black n Tan]

I don't believe it will hit 1.000 with champagne yeast - just that wine type yeast can affect flavour in a less than favourable way (based on my admittedly limited personal experience with trying the same).

Think Mardoo was getting at the same.

I think the flavour impact on a near completed beer would be bugger all.

 

[manticle]

Possibly. As I said - limited personal experience but based on that I would use high abv tolerant beer yeast first.

 

[HBHB]

@hbhb using hydrometer and am confident in it's measurements.
Thermometers seem to be fine. Mash was at 68 degrees for one hour. After the hour recorded temp was 65 which is my normal temp loss in my mash tun.

Cool. As the other guys have indicated, it's most likely a case of lack of disolved 02 and a slight under-pitch of US-05.

I've used CBC-1 yeast by lallemand in such cases and it tends to stop down around 1.018-1.020. The higher alcohol doesn't worry it and it won't throw any unwanted flavours either. Pretty sure Ross would have it down there. Benefits from rehydration and running it at about 20 deg C. Within a week, it should be at terminal gravity. It's a good choice for re-yeasting RIS and big Belgians for bottle conditioning when your yeast is already shagged out from the high Abv.

 

[Mardoo]

I have tried EC1118 champagne yeast versus WL099 and there was definitely flavour stripping by the EC1118 champagne yeast. It stripped a very noticeable quantity of the stonefruit esters I (or rather the yeast - WY1469) worked hard to get into the base beer. The WL099 covered up some of the esters as well, but they showed themselves again after conditioning, whereas they were just gone with the champagne yeast. I myself definitely won't be using champagne yeast in future RIS fermentations. HBHB's advice about CBC1 is well taken. I haven't used it for RIS, but I've used it for other bottlings and it's great, neither leaving nor stripping noticeable flavour.

 

[HBHB]

I have tried EC1118 champagne yeast versus WL099 and there was definitely flavour stripping by the EC1118 champagne yeast.

Have found the same with EC-1118, but haven't ever tried WL099 in those situations. Better than nothing, but less than ideal.