Wyeast 1084 attenuation

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Wyeast 1084 attenuation

Postby Banjo-guy » Sun Jan 07, 2018 10:51 pm

I am fermenting an Oatmeal Stout. The OG is 1.061. The FG has been at 1.024 for a few days. How do I drop it a few points? I think 1.024 FG is too high for a stout.
I have raised the temperature and swirled the wort around to try and get it going but no luck. Don't want go go much below 1.020 maybe 1.018.

I'll admit I was a little lazy with the starter and only made a vitality starter. I let the starter go for 5 hours before pitching so I might have been under pitched. I ran oxygen for a minute before pitching.
Is there a dry yeast that would get this just a little lower? I just read that I could use amylase. This is the first I've heard of that item.

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Re: Wyeast 1084 attenuation

Postby bpgreen » Mon Jan 08, 2018 12:20 am

Amylase is an enzyme that converts unfermentable sugars into fermentable sugars. So if you've got a stuck fermentation, adding some amylase can kick start it and get the gravity to drop. A relatively cheap source of amylase is Beano. You can add a couple of Beans tablets to your fermenter and they'll start converting the unfermentable sugars into fermentable sugars, and the yeast will happily convert them into alcohol and CO2.

The amylase will quickly convert some of those sugars, and then will slowly and quietly convert the rest of them.

If you're paying attention and thinking this through to the end (as I did not the one time I used Beano), you've recognized the problem.

The amylase will slow down, but it won't stop (unless you stop it*). It will slow to the point where you'll take gravity readings several days apart and see no change, so you'll bottle. Then it will continue converting the sugars in the bottles. And the yeast will find those newly fermentable sugars and convert them to alcohol and CO2. In case you're wondering, a beer can actually be carbonated to the point where it will stain the ceiling when it's opened.

*The amylase enzyme will convert sugars until or unless it is deactivated. You can deactivate it by heating it past the point where it will remain active. I forget what that temperature is, but I think it's above 150F. Obviously, if you heat the wort to a temperature sufficient to deactivate the amylase, you've also killed the yeast. So if you're naturally carbonating, you'll need to add new yeast.

As for dry yeasts that can drop the gravity lower, the answer (as it is so often) is that it depends. From the sounds of things, you should have gotten down to about 1.018 as-is (that's close to the low end of the attenuation range for 1084).

Can you give us some more details about the brew? What was the recipe? Was it all grain? Extract, Partial Mash? If you mashed, what was the mash temperature?

I mostly use dry yeasts, and some of those would likely be able to drop your FG unless something else is going on. But they may also drop your FG more than you'd like, so let's make sure we're covering all of our bases. If we use the wrong dry yeast, we could end up dropping the FG lower than you want.

Did you try adding yeast energizer? That's similar to yeast nutrient, but is aimed at stuck fermentations rather than at getting a healthy start. If I remember correctly, yeast nutrient is usually mostly nitrogen, and yeast energizer adds things like vitamins, yeast hulls, etc.

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Re: Wyeast 1084 attenuation

Postby mashani » Mon Jan 08, 2018 1:03 am

I'd stay way from the enzyme for the reasons BP mentioned. It is simply a dangerous thing to do post boil unless you plan on re-heating your beer.

You could try a couple of things and/or a combination of things.

Try yeast energizer as BP mentioned.

Pitch some Nottingham dry yeast. If there is anything left for there to eat that the 1084 didn't take out the Nottingham will do it. If you keep temps 63 or < it won't really affect the flavor. The only thing is it might eat more then you want, depending on if the sugars are fermentable or not (depends on how you mashed, I don't know).

Or you could try adding a little bit of sugar boiled in some water. This will wake up the yeast and get it fermenting again because sugar is easy food. SOMETIMES (not always) this can cause the yeast to actually knock off a few other fermentable things in the process. This is one of the reasons some of us sugar feed Belgians when using some Belgian yeast strains, we get a few more points of attenuation by doing this.

A mix of the yeast energizer and some sugar might work well. Just a little bit of sugar (4oz?), just something that gets the yeast to have something really easy to get started on and get going again. Worst side effect is slightly higher ABV, which if anything will help balance the extra malt even if it doesn't "work".

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Wyeast 1084 attenuation

Postby Banjo-guy » Mon Jan 08, 2018 4:18 pm

Here is the recipe that I used.
For 2.5 Gallons

4 lb pale malt
8 oz flaked oats roasted in oven
6 oz Victory malt
4 oz 80° L caramel malt
4 oz black malt
3 oz chocolate malt
3 oz pale chocolate malt
1 oz Golding pellet hops, (60 min)
Wyeast Irish Ale 1084.
Mash 75 minutes@ 154
Fermented at 64 degrees for 4 Days, ramp up to 68 degrees over 3 Days.
Last edited by Banjo-guy on Tue Jan 09, 2018 6:55 am, edited 1 time in total.

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Re: Wyeast 1084 attenuation

Postby bpgreen » Mon Jan 08, 2018 4:39 pm

Nothing jumps out as something that would cause it to finish so high.

I'd suggest following the suggestions in mashani's post.

Obviously, if you're planning to wash the yeast for reuse and you decide to pitch some Nottingham, you'll want to harvest before pitching the Nottingham, or you'll end up with a blend and now way of knowing how much of it is 1084 and how much is Nottingham.

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Re: Wyeast 1084 attenuation

Postby Beer-lord » Mon Jan 08, 2018 8:23 pm

I had this problem for awhile and narrowed it down to 2 things, aeration and not enough yeast. A minute of oxygen is plenty so you've got that covered so maybe the yeast was a bit old and wasn't able to do their job. In my beers, I keg so I just kegged and enjoyed.
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Re: Wyeast 1084 attenuation

Postby Banjo-guy » Tue Jan 09, 2018 11:44 am

I racked to a keg, harvested the 1084 and pitched a packet of Nottingham. I lowered the temp to 63.
If it dries out too much I’ll just call it a Dry Oatmeal Stout.
I’m going to brew this again very soon and it will be interesting to see the difference if one brew has a drastically lower FG.


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Re: Wyeast 1084 attenuation

Postby bpgreen » Tue Jan 09, 2018 1:12 pm

Let us know how it turns out.

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Re: Wyeast 1084 attenuation

Postby Banjo-guy » Tue Jan 09, 2018 5:18 pm

Thanks for the help!


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Re: Wyeast 1084 attenuation

Postby Banjo-guy » Fri Jan 12, 2018 9:00 pm

I pitched a full packet of Notty and after 3 -4 days the gravity hasn’t move at all. It’s still stuck at 1.024.

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Re: Wyeast 1084 attenuation

Postby bpgreen » Sat Jan 13, 2018 1:20 am

Before doing any of the following, give it a full week instead of 3-4 days.

I'm stumped. Nottingham is usually a beast. I use it a single pack in 5 gallon batches in the mid 50s in the winter and get attenuation approaching (and occasionally exceeding) 80%. I generally do partial mashes and don't mash as high as you did, but I'd still have expected it to chew through more of the sugars than it did.

When I saw that Notty didn't do anything, I took another look and saw that it was an all grain batch and you mashed at 154, which is going to favor alpha amylase, resulting in more unfermentable sugars and a fuller body. But I plugged all of your ingredients into BeerSmith, and selected full body. With a brewhouse efficiency of 73%, I got an expected OG of 1.061. Selecting full body had it give a mash temperature of 156 (so slightly higher than yours). With those parameters, it gave an expected FG of 1.018 (with just the 1084).

I think the yeast energizer would be a waste of time and money. You added some fresh Nottingham yeast and Lallemand says that Nottinghams already has a reserve of carbohydrates and unsaturated fatty acids so aeration isn't required.

I wonder if your mash temperatures were higher than you thought, leading to more unfermentable sugars. But I'm not sure if that would really do this. I don't know that beta amylase is very active at 154, anyway, so most (if not all) of the conversion was already being done by alpha amylase.

So, as I said, I'm stumped. You've added Nottingham and it hasn't done anything. Mashani's fear with it was that it might ferment too much (I considered suggesting it in my first post, but didn't for that reason). Since Notty ships with the UFAs and carbohydrates it needs, yeast energizer shouldn't be needed. If your water is really low in minerals, it's possible that you should add some yeast nutrient (something like DAP or food grade urea--don't cheap out and grab some from the fertilizer bag). But if that were the case, you'd have seen poor attenuation on every all-grain batch you've done, and that doesn't seem to be the case (unless this is your first all-grain batch).

At this point, I think I'd be inclined to add some white sugar as makhani suggested. Theoretically, you should be ok just dumping it in, but if I were you, I'd boil it first and let it cool before adding it. If you boil it, make sure you use enough water for the sugar and also make sure you don't boil it long enough to turn it into candy (you probably already know that, but I'd rather tell you something you know than omit telling you something you don't know). As mashani said, that might wake up the yeast, and if it doesn't, it will at least add some alcohol to balance out the extra malt.

Are you kegging this or bottling it? If you're kegging, I'm much less concerned that there's some sort of "pause" involved. I've had some batches made with older extract that seemed to be done, but the gravity dropped while they were in the keg. If you keg and that happens, the beer is over carbonated for the first few pours. If you bottle and that happens, you get bottle bombs.

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Re: Wyeast 1084 attenuation

Postby Banjo-guy » Sat Jan 13, 2018 6:02 am

Doh!!! Technology makes you stupid. I’m sure the Tilt’s battery is dead.
Sometimes the old ways are just better.
I’ll pull a sample later today.


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Re: Wyeast 1084 attenuation

Postby Beer-lord » Sat Jan 13, 2018 12:14 pm

I've waited until today to post on this knowing that I was going to check on the stout I brewed last weekend and knowing that I mashed at 156 and would have a story to tell too. I don't brew lots of stouts but quit mashing them so high because of final gravity problems. However, this time I figured I'd try again. Years back I had lots of problems like this but found out that fresh, potent yeast and oxygen was all I needed. But in this stout, starting at 1.066 (FG should be 1.108), I'm stuck at 1.030. It's still early I know but I also know it will only drop to about 1.025. Since I keg, I don't really worry about it as long as the beer isn't tasting sweet. I'll add some 05 just as a precaution but I can say that the yeast was fresh and more yeast than needed and I added oxygen so to me, it all comes down to the mash temperature and fermentable sugars.
So my advise is to mash below 154 and just live with it. My adding more yeast to something that will not ferment is only to make me feel better and probably won't do much but as I said, I can live with it and will likely have an under 5%, still drinkable and tasty stout.
We live and learn!
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Wyeast 1084 attenuation

Postby Banjo-guy » Sat Jan 13, 2018 1:40 pm

Banjo-guy wrote:Doh!!! Technology makes you stupid. I’m sure the Tilt’s battery is dead.
Sometimes the old ways are just better.
I’ll pull a sample later today.


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So it turns out the Tilt was right on and my battery is not dead.
I pulled a sample and it measured exactly 1.024.
Now I’m really confused about the fg.
I mashed at 154 and it dropped a degree by the end of the 75 minute mash.


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Re: Wyeast 1084 attenuation

Postby Banjo-guy » Sat Jan 13, 2018 6:29 pm

Beer-lord wrote:I've waited until today to post on this knowing that I was going to check on the stout I brewed last weekend and knowing that I mashed at 156 and would have a story to tell too. I don't brew lots of stouts but quit mashing them so high because of final gravity problems. However, this time I figured I'd try again. Years back I had lots of problems like this but found out that fresh, potent yeast and oxygen was all I needed. But in this stout, starting at 1.066 (FG should be 1.108), I'm stuck at 1.030. It's still early I know but I also know it will only drop to about 1.025. Since I keg, I don't really worry about it as long as the beer isn't tasting sweet. I'll add some 05 just as a precaution but I can say that the yeast was fresh and more yeast than needed and I added oxygen so to me, it all comes down to the mash temperature and fermentable sugars.
So my advise is to mash below 154 and just live with it. My adding more yeast to something that will not ferment is only to make me feel better and probably won't do much but as I said, I can live with it and will likely have an under 5%, still drinkable and tasty stout.
We live and learn!

Your brew sounds a lot like mine. I didn’t realize the higher mash temperature would make such a difference in the final gravity. What yeast did you use?


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