Imperial Stout, complete Fermentation

[Brewshna]

Hi All,

so i brewed a very high gravity pastry stout at OG1.130. The FG was supposed to be 1.050. It stoped at 1.060. I used Lallbrew London yeast and didnt count in the not fermenting of maltotriose, so i guess thats whats happened.
I pulled 200ml of beer, mixed it with 100ml of water, heated it to kill nasties and added yeast nutrient, cooled to 22C and pitched some Nottingham. Nothing.
So has anyone got any suggestions on how i can lower the FG? It's too sweeet, even for a pastry stout. I still have 3 packs of CBC yeast, could that work??

Thanks
Matt

 

[DBhomebrew]

CBC won't touch it, that's why it's a bottling yeast. Other yeasts which might may have a hard time getting started in such a high alcohol environment.

Are you sure it's stuck? A big beer like that may continue to knock off a few points over the next few weeks. How long has it been in the fermenter?

 

[Brewshna]

it reached 1.060 a week ago, i increased temp to 26C and shook it a few times. Been like that for a week. I really need to get the gravity down a bit, I put so much work and money into it. I really regret using London yeast, should have gone straight to Notty.

 

[DBhomebrew]

How long did it take to get to 1060?

 

[Brewshna]

It took one week, or shorter.

 

[DBhomebrew]

So, two weeks total?

 

[Brewshna]

A friend just suggested adding sugar to bump alcohol, it should dry it out a bit. 700g dextrose would lift it to 12% and 1.055. But if the sugar doesn't ferment im f***ed

 

[Brewshna]

Yes two weeks

 

[DBhomebrew]

Don't add sugar. It'll raise ABV and if you're lucky FG will be exactly the same.

Sugar only dries out a beer if it replaces malt.

 

[DBhomebrew]

Yes two weeks

Give it another two weeks. You can't rush big fermentations.

 

[Brewshna]

I was aiming for just over 11% and I'm just under 10%

 

[Brewshna]

What Temperature do you suggest?

 

[DBhomebrew]

Give it time. In a high alcohol environment those yeast are working as hard as they can. You might still get a few points.

~20°C

 

[Brewshna]

Just didn't move within a week and I heated it to 26C. Very upsetting.
Thanks a lot for your input

 

[DBhomebrew]

Hardest part about brewing beer is the waiting.

 

[Brewshna]

That it's true, patience isn't my strong side

 

[sibelman]

Frustrations like this haven't stopped me from brewing higher-gravity beers. My most recent foray into barley wine has been moved into a closet where I can ignore it for weeks or months.

 

[Cheshire Cat]

I suspect the high alcohol has killed the yeast. Try throwing in a high alcohol tolerance yeast like M31 tripel yeast.

 

[Brewshna]

Frustrations like this haven't stopped me from brewing higher-gravity beers. My most recent foray into barley wine has been moved into a closet where I can ignore it for weeks or months.

I brewed an Imperial stout and left it in a Glas bulb for 300days, tastes great. This one was better planned (but not good enough) but I put so much stuff into it that's it's really expensive. Loads of lactose, maltodextrin and PB2. I really need this to be good

 

[DBhomebrew]

Where did you get your FG estimate from? A published recipe? A recipe you built in software?

 

[Brewshna]

I suspect the high alcohol has killed the yeast. Try throwing in a high alcohol tolerance yeast like M31 tripel yeast.

London has a tolerance of 12%, so should be OK.

 

[Brewshna]

It's my own recipe and from Brewfather. I was very conservative with unfermentables. Was expecting that or even lower

 

[DBhomebrew]

I'm not sure about Brewfather, but many softwares don't consider grist makeup in their FG estimation. Roasted malts and crystals are less fermentable. Lactose, of course.

I'm not saying this is definitely true, but it's quite possible your estimate is based on a 'typical' wort.

 

[Brewshna]

I'm not sure about Brewfather, but many softwares don't consider grist makeup in their FG estimation. Roasted malts and crystals are less fermentable. Lactose, of course.

I'm not saying this is definitely true, but it's quite possible your estimate is based on a 'typical' wort.

Yes good thought. I set every malt over 400EBC to not fermentable to take that into account. You're right that most calculators don't do that well. Lactose and maltodextrin are automatically set to not fermtened

 

[Brewshna]

I forgot to mention, the yeast is at about 63% attenuation now. I was (probably wrongly) hoping for 70%.
Thats another reason i think it's done.

 

[bwible]

When you make a big beer like this, its a good idea to make a similar style smaller beer first and use that to build lots of yeast. For example you make a dry stout first. Then you brew the big RIS the same day you rack off the dry stout. Put the RIS right on top of the same yeast cake. Also helps to use yeast nutrient and yeast energizer.

I have not been using dry yeast. For your big beers your best bets are:

11% tolerance - 1028, 1056

12% tolerance - 1084, 1728

Some of the others will go to 10%, but these 4 are your best bets and I try to stay away from Belgian yeasts for these beers. 1728 has been one of my favorites for big beers over the years.

I’ve made the mistake of trying to make a 10% English Barleywine with 1968, because it was what I had. 1968 only has a 9% tolerance. Even after building it up, the resulting beer was candy sweet and would not carbonate in the bottles. I ended up using some of it as top off for future English Barleywines and dumped the rest.

As an absolute last resort you could try champagne yeast. Goes to 18%. Thats been an age old recommendation. It won’t make the best beer but it might get you something at least drinkable.

 

[Brewshna]

I only use dry yeast, easier to get in Germany. I used Lallbrew london which has a tolerance of 12%. Ill go for Nottingham next time, 14% tolerance.

 

[DBhomebrew]

Champagne yeast will hit high ABV in a simple sugar must, not a long chain rich wort. It won't touch those longer sugars.

 

[DBhomebrew]

I only use dry yeast, easier to get in Germany. I used Lallbrew london which has a tolerance of 12%. Ill go for Nottingham next time, 14% tolerance.

If you want the flavors of a lower attenuating yeast, you can pitch the London as you normally would, then on day 3 pitch the Notty.

The trick is to pitch the workhorse strain after the flavor strain has done its work, but before the beer becomes too alcoholic/acidic for the new strain to take over.

 

[Brewshna]

Is there a yeast that will break down complex sugars like maltotriose, but is still tolerant of 10% alcohol??

 

[Klinzai]

Is there a yeast that will break down complex sugars like maltotriose, but is still tolerant of 10% alcohol??

Try K1V-1116. Tolerance around 18% and supposedly will handle maltotriose.

 

[Brewshna]

Very cool, will check it out. Thanks

 

[DBhomebrew]

Most beer yeasts will handle maltotriose, albeit to different levels of completion. Some beer yeasts can handle high alcohol. Some can handle lots of maltotriose. Some can handle both. Notty can do it if treated properly. Some other beer yeasts are STA1-positive, diastatic. They can break down long chains into smaller ones. Saisons are a clear example, they're a dry style for a reason. Some British yeasts are related to Belgians and carry some of their characteristics.

 

[Brewshna]

I'm rater confused that Notty did nothing in the 200ml I took out of the beer. Did expect activity.

 

[DBhomebrew]

Just because a yeast can bring a fresh high gravity wort to over 10%ABV, doesn't mean it can establish itself and take off in a 10%ABV beer.

 

[Brewshna]

I mixed it with water, should have been at apr. 6%. I don't expect it to drop so my brain is not stopping thinking about a possible solution. Maybe adding coco nibs would add bitterness and perceived dryness

 

[tracer bullet]

I didn't see how much yeast you used. Maybe it wasn't quite enough? My last 5 gallon Imperial I threw in 3 packs. 2 Should be enough but I'm me and wanted to be sure. 1 single pack could be a reason for a low attenuation?

 

[Brewshna]

I used 3. Maybe 4 would have been better

 

[Brewshna]

Thanks everyone for the help, by the way

 

[Brewshna]

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