Stuck Imp. Stout. How far will champagne yeast take it down?

[SteveHeff]

Hello. I have 6 gallons of a 1.102 OG Imperial Stout. I built a 1.060 yeast starter (Mangrove Jack M15, 670 mL over 2 days at room temp (20-21C). The yeast was pitched when fermentation temp. was reached (19C-66F). The issue is after two weeks at 66-70F, my beer is stuck at 1.040.

It hasn't dropped any points in the last 5 days. 3 days ago I pitched a 500 mL starter of 1.050 Danstar Cask yeast and it has not yet shown up to the party. It is still very stuck at 1.040.

The alcohol tolerance on the M15 is 8%. I wish I was more observant on the tolerance. So it's stone cold at 8.14% when I was going to 9.7-10.2%.

I have been debating champagne yeast in the secondary but I have no idea what kind of flavors to expect as well as how many points it will drop the gravity. Here's the recipe:

13# maris otter
3.75# Munich 10L
2# oats
1.75# Chocolate malt
1.5# C60
12 oz Roasted Barley
8 oz special B
8 oz black patent

Scratching my head, but I'm left with a beer that I can definitely ferment out quite a few more points. Beersmith has the final gravity at 1.018 and I would like to be close to that figure. Thanks.

 

[Smellyglove]

My experience with M15 is that it craps out very early. Horrible yeast imo. but that's my experience.

Did you measure with a hydrometer?

I'd add an active starter of something else than champagne yeast, as champagne yeasts only eat simple sugars, and those should be mostly if not all gone by now. But M15 might have crapped out early leaving some simpler sugars behind.

don't believe in FG in from Beersmith. It's a calculation based on default values in beersmith. A beer at 1.102 would imo taste better at 1.025ish than down at 1.018.

 

[Dcpcooks]

A couple of things to think about going forward. Starters are best built with 1.040 wort. You want to grow a population rather than get your yeast used to higher gravities. I haven’t done the math but I’m guessing you under pitched in addition to using a yeast that doesn’t excel in high abv beers.

You have a large percentage of dark roasted and caramel malts that produce long chain sugars that are harder for yeast to break down and ferment. Those malts are used to add body to beers and that’s what you have. A big body beer. Couple that with your yeast and starter volume it’s very possible your close to your final gravity. Your yeast are starting to struggle due to the sugar types remaining and the abv.

CBC is used to produce carbonation in high abv beers not necessarily to ferment high abv beers. It’s also a killer yeast. It will secrete a protein that limits or kill other yeasts ability to function. It’s best used at 72 degrees.
Champagne yeast is alcohol tolerant but not a great yeast for long chain sugars. So it may help a bit but not a lot. It won’t impact your flavors at this point in fermentation. Most flavors are created during the first 2-4 days of fermentation. That’s a combo of yeast choice, grain bill and temp control.

Two weeks isn’t that long of a primary for a beer of this size/style. I routinely leave my RIS in primary for three to four weeks and then barrel age them for another month. I usually get a few additional points from at the end of primary and in the barrel. I’d bring it to 72 for another week and see what you get. I’d also taste the beer to see if your in balance. If your not happy and really want to try to another yeast I’d make another starter with a few packs of cbc-1, 3711 or champagne yeast and pitch it at the peak of growth. It this point you’ll need a very health active and large pitch to give it the best health and chance to ferment the longer chain sugars you have remaining in the presence of CBC-1.

Next time you make a RIS design it so you get a greater percentage of gravity points from Maris otter and lower the Munich 10. Mash it on the low end of the curve. Make a big starter with Nottingham and oxygenate it with pure O2 prior to pitching yeast.

I’d bump your current batch to 72 and give it a week before you add anymore yeast if it were my beer. I’m pretty sure you’ll like the beer if you can get just a few more gravity points out of fermentation. 1.036 would be a reasonable FG at this point imo.

 

[mj1angier]

A couple of things to think about going forward. Starters are best built with 1.040 wort. You want to grow a population rather than get your yeast used to higher gravities. I haven’t done the math but I’m guessing you under pitched in addition to using a yeast that doesn’t excel in high abv beers.

You have a large percentage of dark roasted and caramel malts that produce long chain sugars that are harder for yeast to break down and ferment. Those malts are used to add body to beers and that’s what you have. A big body beer. Couple that with your yeast and starter volume it’s very possible your close to your final gravity. Your yeast are starting to struggle due to the sugar types remaining and the abv.

CBC is used to produce carbonation in high abv beers not necessarily to ferment high abv beers. It’s also a killer yeast. It will secrete a protein that limits or kill other yeasts ability to function. It’s best used at 72 degrees.
Champagne yeast is alcohol tolerant but not a great yeast for long chain sugars. So it may help a bit but not a lot. It won’t impact your flavors at this point in fermentation. Most flavors are created during the first 2-4 days of fermentation. That’s a combo of yeast choice, grain bill and temp control.

Two weeks isn’t that long of a primary for a beer of this size/style. I routinely leave my RIS in primary for three to four weeks and then barrel age them for another month. I usually get a few additional points from at the end of primary and in the barrel. I’d bring it to 72 for another week and see what you get. I’d also taste the beer to see if your in balance. If your not happy and really want to try to another yeast I’d make another starter with a few packs of cbc-1, 3711 or champagne yeast and pitch it at the peak of growth. It this point you’ll need a very health active and large pitch to give it the best health and chance to ferment the longer chain sugars you have remaining in the presence of CBC-1.

Next time you make a RIS design it so you get a greater percentage of gravity points from Maris otter and lower the Munich 10. Mash it on the low end of the curve. Make a big starter with Nottingham and oxygenate it with pure O2 prior to pitching yeast.

I’d bump your current batch to 72 and give it a week before you add anymore yeast if it were my beer. I’m pretty sure you’ll like the beer if you can get just a few more gravity points out of fermentation. 1.036 would be a reasonable FG at this point imo.

LOL, yeah what he said!!

 

[Calder]

1.75# Chocolate malt
1.5# C60
12 oz Roasted Barley
8 oz special B
8 oz black patent

5 lbs of specialty malt doesn't help. These contribute a lot of unfermentable sugars. But unless you mashed really high you should have a lot of fermentables left in there.

My advice is '3711'.

 

[SteveHeff]

So the plan is to keep it at 70+ for the next week or so. After that, I'll transfer to my secondary and I may pitch champagne yeast, depending on where the gravity is. I typically build my starters 2-3 days out from brew day...this one was a bit rushed. Also, I've never used M15 before and I don't think I'll use it again. I'm a big fan of 1084 but I have not used it in such a large recipe before.

I realize that there is a lot of specialty malt, however this a Ten Fidy clone from Oskar Blues. I'm in a position where if this turns out well, I'll brew it again, however I'll exchange some of the Munich for Maris Otter as well as build a BIG starter with a more alcohol tolerant yeast. I'm owning these mistakes...I think most people learn more from mistakes.

 

[Northern_Brewer]

I've not used M15 but have some in the fridge. I think it's just a bit misunderstood, the poor thing gets thrown at beers like Ten Fidy when its natural home is more something like a mild, it's very much a yeast in the English tradition of brewing. But people throw it at 10% beers, get upset when it doesn't behave like Chico, and dismiss it as "a horrible yeast". Having said that, if it's a dry version of the strain I think it is then it could be a really interesting yeast for boosting the mouthfeel and esters on a session NEIPA, which is why I've got it. But if it doesn't work on a NEIPA then I won't get too upset, I'll just save it for the kind of beers it was intended to brew.

As an aside - a lot of dry yeasts are multistrain blends, so if you grow them from a starter then you'll end up skewing the mix of strains and it won't necessarily brew as you intend it. Nottingham is definitely a blend, and I suspect many Mangrove Jack yeasts are as well, given their reputation for drifting after a few generations. If you want lots of yeast, grow a starter from a single-strain liquid yeast, or buy more packets of dry yeast.

Going back to the matter in hand, if you've reached the point at which you're poisoning your M15 then increasing the temperature won't help. And a simple-sugar-munching yeast like a wine yeast or CBC-1 will only make life harder for any proper beer yeast that you end up putting in there, unless you add some amylase enzyme. But if you're over 8% I'd say "Thank you M15, may you rest in peace" and get a proper beer yeast on the case.

The obvious candidate is WLP540 Abbey IV, allegedly from Rochefort (1762 may be equivalent if you've a Wyeast shop, but I can't guarantee it). Despite the name it's actually a POF- British yeast that's obviously right at home in strong, dark beers so alcohol tolerance is not an issue. Maybe use starters stepped in increasing strength, help it with a bit of sugar in the beer just to help it find its feet, but that's what I'd use in your position.

 

[SteveHeff]

You know, I had some quick second thoughts on using this yeast. My beer shop guy was out of 1272 and I was looking for a different yeast. He said that it would be a good yeast to try on this beer. My fault for putting it in his hands, but he has been right more than wrong on other beer advice.

I will definitely utilize a different strain if I ever brew this again. I think Abbey Ale II would be a fantastic yeast to make this beer ferment properly and the give the beer a subtle fruit characteristics, as well. It will likely be a year before I brew this, again, but I'll make sure to pick the thread up after doing so.

Thanks for the advice. It was all well received.

 

[jrgtr42]

You have a lot of specialty grains in there. What were your mash numbers, temp and so forth, and what was your OG compared to BeerSmith estimated?

 

[SteveHeff]

You have a lot of specialty grains in there. What were your mash numbers, temp and so forth, and what was your OG compared to BeerSmith estimated?

So I mashed at 150 for 90 minutes. At the end of 90 minutes, my mash temp was 144. I added a gallon of boiling sparge water to elevate the temp to 155. I then ran my full volume through the grain bed. It took 3 hours to do. I ended up grinding my grain far too finely.

I finally ended up with 8.5 gallons of wort, which I boiled for 90 minutes, trying to get the volume down. After 90 minutes of boiling, I was left with just over 7 gallons of wort. 6 of which went into one fermenter and the remaining volume was diluted with 2 gallons of 1.018 wort.

My OG was 1.102. Beersmith calculated 1.106 at 5.5 gallons at 70%. I am perfectly happy with my OG. But it does look like I'll transfer to secondary, add a bit more sugar to the party, and add another yeast starter with an abbey strain. Hopefully that will move it along a touch more.

I'm giving it another week in the primary before I move it. No reason to rush it. I'll have more to report back in a few weeks. Thanks for tuning in.

 

[stieg000]

I've brewed imp stouts many times, you have more specialty grains in yours than mine and only a slightly higher FG. I'd say it's done fermenting. Rousing the yeast and bumping the temp a few degrees will usually give you a couple more points but that's it.

 

[SteveHeff]

The yeast are finished. They don't want any more of these residual sugars. The tolerance on the yeast is 8%, meaning that no amount of rousing or warmth will alter the attenuation of the strain. Northern Brewer gave some solid advice, which I intend on following. It's not going to hurt anything if I add some sugar and a starter of an abbey strain. However it may end up dropping my gravity the 8-12 points that I'm looking for.

 

[Comfort_Zone]

If there is anything left in there you can pitch 3711, that's a great backup yeast. Don't use champagne or cbc-1. They're not gonna do anything and they're both killer yeasts.

 

[SteveHeff]

I'm currently building my starter with 1762 Abbey Ale II at 1.044. Over the next few days, I'll feed some of the beer/wort into the starter in order to allow it to acclimate to the high alcohol environment. Maybe either Sunday or Monday when I pitch the yeast, I'll toss some corn sugar syrup in as well.

 

[Comfort_Zone]

That's a great yeast for this style of beer. Best of luck and keep us updated!

 

[SteveHeff]

Now that the yeast are at high krausen, I added 60 grams of honey to the starter as well as 200 ml of the beer. I taste tested the beer, too, and found that it is incredibly sweet. I'm glad I decided to do the extra work and attempt to decrease the gravity. More to report on Monday.

 

[SteveHeff]

Update: I pitched the 4 day starter, today. I made a DME syrup, 2 cups DME/1 liter water, and poured that in along with the starter. Gravity is at 1.038 with the syrup and starter. I'll check back on it Thursday or Friday.

 

[SteveHeff]

The yeast is slowly chewing through the sugars. Current gravity is 1.026.

 

[Comfort_Zone]

That's great! It'll take some time but you'll get there.

 

[SteveHeff]

Stable gravity at 1.024.

 

[Comfort_Zone]

That's a solid FG, looks like that yeast definitely helped.

 

[Northern_Brewer]

Must be close to 80% attenuation allowing for the extra fermentables you put in.

More importantly, how does it taste?!?!

 

[SteveHeff]

It's deceptively smooth with a hint of oak and bourbon. It has lost the vast majority of the cloyingly sweetness it had before. I really don't think I'll have to age it, all that long, or nearly as long as I originally thought. I'm going to bottle it up in the next few days (I have a few class finals this upcoming week). I'll wait another month before cracking one open. I'll check back in, and until then, cheers.

 

[SteveHeff]

The verdict is in. It's a very good beer. The fermentation schedule has altered very little with the flavor profile. But given that the beer has a good amount of specialty grains, I didn't think I would have any yeast off flavors. It's still a bit "hot" from the bourbon, but that seems to change depending on how long a bottle has been carbing.

I plan on keeping my remaining twenty 22oz bombers in my basement for the next 6 months, or so. This way there will be plenty of good beer for Christmas and beyond.

 

[Comfort_Zone]

The verdict is in. It's a very good beer. The fermentation schedule has altered very little with the flavor profile. But given that the beer has a good amount of specialty grains, I didn't think I would have any yeast off flavors. It's still a bit "hot" from the bourbon, but that seems to change depending on how long a bottle has been carbing.

I plan on keeping my remaining twenty 22oz bombers in my basement for the next 6 months, or so. This way there will be plenty of good beer for Christmas and beyond.

Glad to hear it worked out!