Low attenuation due to extract?

[mcleanmj]

I recently brewed a Bourbon County clone recipe modified from:
https://homebrewsupply.com/content/HBS All Grain Recipes/AG_INS_BourbonCountyStoutClone.pdf
With my current set up, I can only handle an 8-gallon mash, so I used about 18 lbs of grain, 1 lb of table sugar, and 8 lbs of liquid extract. My boil off was much lower than expected and I ended up with an OG of 1.113. Brewfather tells me I should hit an FG of 1.026 @ 75% attenuation.

I stepped up a 4 liter starter of WLP001 over the course of several days. I cold crashed it overnight and decanted it and pitched the thick yeast slurry. I did not use pure oxygen for aeration, but I poured the wort back and forth between 2 buckets like 7 times and shook the hell out of it. I also added 2.5 teaspoons of WLP yeast nutrient to the boil.

Fermentation was roaring, and after 10 days I took a SG reading, which was 1.034. Way high, with only 68% attenuation (sitting at about 10.5% abv). I was not happy about that, but I had saved some harvested WLP001 in case this happened. I then made a 2 liter starter with the harvested yeast and let it go 48 hours. I then cold crashed it overnight. The resulting yeast cake was huge. I decanted the liquid and pitched the thick yeast slurry into the wort. 48 hours later and no airlock activity. I checked SG, still at 1.034. I stirred up all the yeast cake and increased the temperature but I'm not expecting anything to happen. I haven't done a forced fermentation test yet. I did also read after the fact that I should have pitched the full 2 liter starter at high krausen instead of chilling and decanting.

I've hit my expected FG on every all-grain beer I've done. However, on two imperial stouts where I've had to supplement with extract I've ended up with 68% and 70% attenuation. Having just pitched an enormous amount of yeast into the wort and not dropping a single gravity point, I'm wondering if the wort is just unfermentable at this point, and if its due to the extract?

Thanks anyone for your insight!

 

[kh54s10]

What was the mash temperature? Have you checked the calibration of both your thermometer and hydrometer? You are not using a refractometer for FG are you?

IMO the extract will make the wort a little less fermentable, but by how much, IDK.

 

[mcleanmj]

Yeah I don't have any issues with the thermometer or hydrometer. I took the readings with my hydrometer. The first reading I took a sample, which I tasted. It was excellent, rich chocolate and coffee flavors, but way too sweet. The second reading I just sanitized the hydrometer and put it in the wort.

Normally I'd say okay I guess I should have used pure oxygen and maybe added the sugars throughout fermentation, but since I just pitched a 2 liter starter and it didn't ferment a single point, I'm thinking poor attenuation isn't the problem so much as unfermentablility. Maybe? I don't know. I'm really shocked the huge yeast slurry I pitched didn't do anything especially since the wort tasted so sweet. I know its got over 10% abv and no oxygen, but still.

 

[mcleanmj]

Oh and mash was about 152 F

 

[Vale71]

Any yeast that you pitch later without oxygenation will not undergo a reproductive phase, so the actual yield in terms of active biomass will be about 1/5th to 1/4th of the same size starter pitched at the beginning after oxygenating. Combine that with the high ABV and the lack of simple sugars which have already been completely fermented by the first pitch and you're making it very hard for the second pitch to actually do anything without it necessarily being an indication that there are no more fermentable sugars in the beer or, if you prefer, that final gravity has actually been reached.

 

[mcleanmj]

Any yeast that you pitch later without oxygenation will not undergo a reproductive phase, so the actual yield in terms of active biomass will be about 1/5th to 1/4th of the same size starter pitched at the beginning after oxygenating. Combine that with the high ABV and the lack of simple sugars which have already been completely fermented by the first pitch and you're making it very hard for the second pitch to actually do anything without it necessarily being an indication that there are no more fermentable sugars in the beer or, if you prefer, that final gravity has actually been reached.

Well ****. Anything I can do now other than package an overly sweet beer?

 

[IslandLizard]

Well ****. Anything I can do now other than package an overly sweet beer?

Glucoamylase?

 

[Steveruch]

What extract did you use?

 

[BrewnWKopperKat]

I've hit my expected FG on every all-grain beer I've done. However, on two imperial stouts where I've had to supplement with extract I've ended up with 68% and 70% attenuation. Having just pitched an enormous amount of yeast into the wort and not dropping a single gravity point, I'm wondering if the wort is just unfermentable at this point, and if its due to the extract?

A forced fermentation test on the liquid extract would validate some of the assumptions that recipe software has to make when estimating OG/FG.

There are older sources (Designing Great Beers, p 15; Zymurgy magazine articles from the 1980s/1990s) that list brands and percentages. Those old articles may be a source for the idea of low fermentability with extract.

IIRC, some of the malt extract providers have current information on fermentability at their web site (check the product information sheets).

 

[ncbrewer]

Any yeast that you pitch later without oxygenation will not undergo a reproductive phase, so the actual yield in terms of active biomass will be about 1/5th to 1/4th of the same size starter pitched at the beginning after oxygenating.

I'd like to read up on this. Can you post a link?

 

[mcleanmj]

What extract did you use?

I'm in Canada and I used a liquid extract produced locally, so not sure ill be able to get much information on it:

https://www.noblegrape.ca/collectio...oducts/malt-extract-liquid-light-1-8-kg-pouch

 

[BrewnWKopperKat]

not sure ill be able to get much information on it:

Maybe a forced fermentation test (OG 1.100) using just the LME?

 

[mcleanmj]

Well, I just drew a 200 ml sample and pitched 3 grams of US-05 in it. We'll see what happens. If it doesn't drop at all, then I guess I'll be drinking a really thick, sweet bourbon stout. I don't think I'm going to throw any enzymes in it, but we'll see...

 

[IslandLizard]

In my early brewing days I had an Old Ale (BCS recipe) of 1.090-some stall at 1.035 using 2 packs of re-hydrated S-04. Mashed at 152F.

Whatever I tried, it didn't budge. I reckoned it had to do with insufficient aeration (didn't have an oxygenation setup then).

Pitching any yeast into 10% beer isn't going to do much.

Here's a recent thread with a similar scenario. This is merely an idea that may help re-ferment your stalled batch.
https://www.homebrewtalk.com/threads/adding-old-brew-to-new.684601/#post-8973193
Basically, brew a new batch (maybe somewhat smaller in size, or gravity) pitching a boatload of healthy yeast. Oxygenate! Or aerate for 12-24 hours.
Wait for it to reach high krausen and start adding your stalled batch, bit by bit, over a few days, making sure it keeps going. Whatever is fermentable should ferment.

 

[mcleanmj]

In my early brewing days I had an Old Ale (BCS recipe) of 1.090-some stall at 1.035 using 2 packs of re-hydrated S-04. Mashed at 152F.

Whatever I tried, it didn't budge. I reckoned it had to do with insufficient aeration (didn't have an oxygenation setup then). Pitching any yeast into 10% beer isn't going to do much.

Here's a recent thread with a similar scenario. This is merely an idea that may help re-ferment your stalled batch.
https://www.homebrewtalk.com/threads/adding-old-brew-to-new.684601/#post-8973193
Basically, brew a new batch (maybe somewhat smaller in size, or gravity) pitching a boatload of healthy yeast. Oxygenate! Or aerate for 12-24 hours.
Wait for it to reach high krausen and start adding your stalled batch, bit by bit, over a few days, making sure it keeps going. Whatever is fermentable should ferment.

Thanks, I'll take a look!

When I was about to brew this beer I was telling my wife I should probably go pick up a small oxygen tank to make sure it was fully aerated and then I got the whole "do you really need a tank of oxygen for making beer at home?" and decided I'd just splash and shake the hell out of it. Well, I guess the answer is yes, you do!

 

[BrewnWKopperKat]

Well, I just drew a 200 ml sample and pitched 3 grams of US-05 in it. We'll see what happens.

US-05 (link) has an alcohol tolerance of 9-11%.

 

[mcleanmj]

US-05 (link) has an alcohol tolerance of 9-11%.

Well, its cheap and on hand. I wasn't going to waste a high gravity purepitch on a fermentation test.

Although this makes me wonder...WLP001 and US-05 are allegedly the same strain, no? Yet WLP001 has a reported tolerance of 15% while US-05 only has 11%? Wyeast 1056 is supposed to be the same strain as well and also has an 11% tolerance. So, are Wyeast 1056 and US-05 the same, but somewhat different from WLP001?

 

[NGD]

Edit: Crap! Got distracted before hitting send. What Island Lizard said.

Do you always use extract from the same supplier? I find it odd there is so little information about it. Makes me think its repackaged. Most of the Briess LME fermentability is around 75-76%. I’m leaning toward not enough oxygenation as well. With grain bills that bill I usually add more 02 between 12-24 hrs after it gets started.

 

[mcleanmj]

Do you always use extract from the same supplier? I find it odd there is so little information about it. Makes me think its repackaged. Most of the Briess LME fermentability is around 75-76%. I’m leaning toward not enough oxygenation as well. With grain bills that bill I usually add more 02 between 12-24 hrs after it gets started.

Yeah, unfortunately. Supply options are pretty limited here, and the only time I have used extract is for huge beers like this.

 

[NGD]

Understood. If I were you I might shoot Noble Grape an email to inquire more information.

I think the Lizard is correct on t being more an oxygenation issue though. I had a similar issue that seem to resolve when I started using pure 02 and doing multiple infusions during early fermentation.

Hope you can figure out a way to iron this out. Sounds like a great brew.

 

[IslandLizard]

When I was about to brew this beer I was telling my wife I should probably go pick up a small oxygen tank to make sure it was fully aerated and then I got the whole "do you really need a tank of oxygen for making beer at home?" and decided I'd just splash and shake the hell out of it. Well, I guess the answer is yes, you do!

From what I've learned over the years, for high(er) gravity worts good wort oxygenation is becoming essential. So is adding yeast nutrients.
For high gravity beers, a second oxygenation, 12-18 hours after pitching, is often recommended. Key is to do the 2nd round before fermentation has started.

Aeration should suffice, but you're not going to get it from splashing, pouring, shaking, whisking, etc. for a few minutes. Besides, the max DO (Dissolved Oxygen) you can reach with air is around 8 ppm, and that takes a while. I have the feeling that 8ppm (if it ever get that high) gets either used up rather quickly or dissipates before the yeast is at her maximum growth potential. Aerating continuously (aquarium pump) for 12-24 hours may give that a fair chance. Care must be taken that active fermentation hasn't started yet, while still aerating or oxygenating.

With higher gravities, adding yeast nutrients becomes more important too. That's how they get to 18-20% beer (e.g., DFH 120).

 

[mcleanmj]

From what I've learned over the years, for high(er) gravity worts good wort oxygenation is becoming essential. So is adding yeast nutrients.
For high gravity beers, a second oxygenation, 12-18 hours after pitching, is often recommended. Key is to do the 2nd round before fermentation has started.

Aeration should suffice, but you're not going to get it from splashing, pouring, shaking, whisking, etc. for a few minutes. Besides, the max DO (Dissolved Oxygen) you can reach with air is around 8 ppm, and that takes a while. I have the feeling that 8ppm (if it ever get that high) gets either used up rather quickly or dissipates before the yeast is at her maximum growth potential. Aerating continuously (aquarium pump) for 12-24 hours may give that a fair chance. Care must be taken that active fermentation hasn't started yet, while still aerating or oxygenating.

With higher gravities, adding yeast nutrients becomes more important too. That's how they get to 18-20% beer (e.g., DFH 120).

Yeah, I knew in the back of my head that I should probably use pure 02, but was too stubborn and lazy. I even said to myself "you are gonna regret this if it gets stuck." I did use a lot of yeast nutrient though. I always add 1/2 teaspoon of White Labs yeast nutrient to every beer, and for this one I think I added 2 full teaspoons.

 

[mcleanmj]

Understood. If I were you I might shoot Noble Grape an email to inquire more information.

I think the Lizard is correct on t being more an oxygenation issue though. I had a similar issue that seem to resolve when I started using pure 02 and doing multiple infusions during early fermentation.

Hope you can figure out a way to iron this out. Sounds like a great brew.

Good idea, I will ask them next I go in. The beer does smell and taste wonderful, but its just too heavy and sweet unfortunately. I took the recipe from homebrewsupply.com and I highly recommend it, it seems to match the real Bourbon County pretty well. Worst case scenario, I will just drink it as is, get nice and drunk, and learn a good lesson for the future.

 

[IslandLizard]

Edit: Crap! Got distracted before hitting send. What Island Lizard said.

You could have left it, some most things are better said twice... but phrased differently. Look around

Do you always use extract from the same supplier? I find it odd there is so little information about it. Makes me think its repackaged. Most of the Briess LME fermentability is around 75-76%.

Yeah, repackaged LME was my thought too.

If you look at what kind of equipment is needed to produce LME, and doing so in commercially viable quantities at an enticing price, I doubt a small maltster could justify such an endeavor. But it could be produced and packaged by a bigger outfit for them.

Homebrewers are actually a very small segment of the buyers' market of condensed and dried malt products. Bakeries and candy makers are the big users. It's also used in pancake and bread mixes, dry dog food, and such.

 

[mcleanmj]

Maybe a forced fermentation test (OG 1.100) using just the LME?

One thing that did just come to mind is that I've measured the gravity of a couple yeast starters with the DME I've used from the same manufacturer. The attenuation on those was 68-70%. Not sure what kind of attenuation is normal for a yeast starter, but it seems poor to me.

 

[BrewnWKopperKat]

The attenuation on those was 68-70%. Not sure what kind of attenuation is normal for a yeast starter, but it seems poor to me.

If you adjust the recipe in Brewfather to use 70% attenuation for the liquid malt extract, how well does the new value predict what happened?

 

[mcleanmj]

If you adjust the recipe in Brewfather to use 70% attenuation for the liquid malt extract, how well does the new value predict what happened?

How do I set the attenuation specifically for the extract? Haven't seen this in Brewfather?

 

[mcleanmj]

If you adjust the recipe in Brewfather to use 70% attenuation for the liquid malt extract, how well does the new value predict what happened?

I checked it with BrewCipher. For the batch I did with dry extract, if I put the fermentability to 70%, it does match up with what actually happened. For this batch with liquid extract, its pretty close (1.032). So, maybe its a combination of this extract being too high in unfermentables as well as needing pure 02.

If the US-05 doesn't have any impact on the forced fermentation sample, I will try champagne yeast and yeast energizer and see if that changes it. If that doesn't trop the OG at all, then to hell with it, its reached its terminus.

 

[dwhite60]

On big beers those last few points can take a while. Won't hurt it to sit another week. Maybe two.

 

[IslandLizard]

as well as needing pure 02

That's a misunderstanding, you can bubble air for 12-24 hours, it would have the same effect: see #21.