HELP with Screwed up batch

[tarcrarc]

I just brewed a oatmeal stout and was aiming to make it as malty as I could. Without thinking of the potential of having a stuck fermentation I mashed at 156 only, with an OG of 1.064 (right where I wanted it). Well the fermentation hit a dead stop at 1.028!!!

My goal is to brew another batch to blend with it but I am not sure the direction to go (aka--which would be easier to obtain):

option #1: brew a very dry stout (FG 1.008)>>blend it with my stuck fermentation stout mentioned above to end up with something around the 1.018 range

OR

option #2: brew another batch to blend with my stuck ferm batch aiming for a russian imperial

Any thoughts?

 

[brewmax25]

What yeast did you use and what was the condition of it before pitching? Was it a reptich? Did you make a starter? Oxygenate your wort?

 

[tarcrarc]

Thanks for your reply:

I made a fine starter with a two vial blend: wlp 007 and 001---on a stir plate. All looked well. Both the starter and wort received pure 02, etc. I did start the fermentation at 62 degrees (which took off as expected. I then bumped it up to 64 after about 24-36 hours or so. I ended up going all the way u to 70 with several attempts to gently stir up the beer---nothing! From reading other forums this temp should be fine for these yeasts, especially 001.

After much contemplation as to what in the world the problem was (since I haven't had this issue in such a long time) the only thing I could come up with was the fact that I ran my mash higher than ever before (156).

REGARDLESS TO THE REASON (although I would like to know other's thoughts about if a mash at 156 should stop fermentation at 1.028 as well)---I am wondering if I could run another mash with a new beer at a temp like 145 and create a very dry beer to blend the two and create something in the middle.

 

[day_trippr]

[...]REGARDLESS TO THE REASON (although I would like to know other's thoughts about if a mash at 156 should stop fermentation at 1.028 as well)---I am wondering if I could run another mash with a new beer at a temp like 145 and create a very dry beer to blend the two and create something in the middle.

Of course you can. And you'd be following a course tread by many before...

Cheers!

 

[tarcrarc]

Thanks man!!! Good to know.

 

[IslandLizard]

Have you checked and calibrated your thermometers? Maybe you were mashing much higher than you thought? 156 is not high for a sweet stout.

I've had a high gravity old ale stall out at 1.030 with S-04, for no apparent reason. Nothing I did could budge it. Maybe the temp dropped a couple degrees and the yeast went dormant?

You could make a new starter (even use part of the yeast cake from the bottom), and pitch a gallon of your stalled stout on that and see if it attenuates, then repeat for the remainder. You may have to add some fermentables (new wort) to get the yeast acclimated first. The alcohol in your stalled stout may deter yeast from resuming, although 1.064 is not that strong.

 

[soccerdad]

Just my 2 cents and others here know WAY more than I do ..

1) does it taste OK when you sample what is in the hydrometer test jar?
2) if so, it will not change dramatically when carbonated since you only want about 1.75 volumes CO2 in a stout .. maybe 2
3) if it truly stays at 1028 and drops no more you will still be at about 4.75 abv which is not a bad level for the style

 

[Calder]

1.028 seems very high to finish at. First question: Are you using an hydrometer? Second question: What grains do you use to get so many unfermentables in there.

I think making another 5 gallons for mixing is just a waste. It is a gamble whether it will work or not. Work on this beer, and separately make 5 gallons of a beer you want to drink.

What could you do? Where would you like it to end?

- You could try pitching an active starter of 3711 and seeing what that will produce. Might get it down another 6 to 8 points. 3711 can take beers down to 1.000 which otherwise would have only gotten down to 1.008 with other highly attenuative Belgian yeasts.
- You could add some Brett and put the beer in the corner ..... it should be ready for next Christmas.

 

[tarcrarc]

Thanks Calder---yea, I did use the hydrometer. I know it's accurate.

Every time I have attempted to pitch additional yeast after a stopped fermentation I got nowhere. Seems others have had success. I'll look into 3711.

This grain bill didn't seem especially high on unfermentables. The bill was close to this:
6% Victory
7% roasted barley
52% 2 row
18% flaked oats
3% pale choc.
3% choc. malt
7% crys. 80
9% rice hulls

 

[tootal]

I think you just answered your own question. The rule of thumb is that you should have at least 80 percent base malt for lighter beers and at least 70 percent on big Porters and Stouts. You have 52 and 6 percent on your base malts. Actually a little more since rice hulls don't count. So you're at roughly 62 percent base malt? I didn't do the math but my point is you should drop the amount of flaked oats and increase your base malts and drop the rice hulls in your calculation. Use them, just don't include them in your percentages so you get a more accurate idea of your recipe.
So IMHO your beer is where is should be because of the large amount of oats. It might be a little chewy but I'm sure it taste good!

 

[Calder]

You have 22% specialty malts. Should be able to get lower than 1.028 even with a high mash.

I guess a thermometer check would be next in the trouble-shooting list to see if you really did mash at 156 F.

The rice hulls will contribute nothing, so should not really be in the % roll-up. The flaked Oats will convert fine and ferment just like 2-row, so are really a base malt for the purpose of recipe design. With 50%+ 2-row, you would have had enough to convert everything. However, that does seem like a lot of flaked oats. How much did you use; about 2.25 lbs in 5 gallons?

 

[IslandLizard]

[...] I didn't do the math but my point is you should drop the amount of flaked oats and increase your base malts and drop the rice hulls in your calculation. Use them, just don't include them in your percentages so you get a more accurate idea of your recipe.
So IMHO your beer is where is should be because of the large amount of oats. It might be a little chewy but I'm sure it taste good!

I meant to quote you too, so I fixed it.
The large amount of oats is not the cause of a stalled fermentation, see my Witbier example below, unless the oats didn't get converted due to extreme high mash temps or some other irregularity.

You have 22% specialty malts. Should be able to get lower than 1.028 even with a high mash.

I guess a thermometer check would be next in the trouble-shooting list to see if you really did mash at 156 F.

The rice hulls will contribute nothing, so should not really be in the % roll-up. The flaked Oats will convert fine and ferment just like 2-row, so are really a base malt for the purpose of recipe design. With 50%+ 2-row, you would have had enough to convert everything. However, that does seem like a lot of flaked oats. How much did you use; about 2.25 lbs in 5 gallons?

Although it looks a lot, I've used 20+% of flaked adjuncts (wheat, oats) and even ended up at 1.006 FG (Witbier). If the OP likes his Stout oaty (as do I) I think that amount is fine. It gives that nice silky mouthfeel.

The OP mentions he's had stalled fermentations before that couldn't be resumed. That's a flag he needs to investigate, why that happens.

Actual mash temp - Thermometer?
Fermentation - steady temps? correct temps?
Too much oxygen?
Yeast quality?

 

[Calder]

Although it looks a lot, I've used 20+% of flaked adjuncts (wheat, oats) and even ended up at 1.006 FG (Witbier). If the OP likes his Stout oaty (as do I) I think that amount is fine. It gives that nice silky mouthfeel.

I didn't have a problem with the Oats, nor thought they contributed to any problem. It just seems a lot. As I said, he had plenty of 2-row to convert everything.

 

[IslandLizard]

I didn't have a problem with the Oats, nor thought they contributed to any problem. It just seems a lot. As I said, he had plenty of 2-row to convert everything.

No, you're right, you didn't have a problem with that. It should convert completely with the 2-row. You only mentioned it was a lot, not a valid cause for a stalled fermentation.

I actually meant to quote tootal too in that post. He said the beer should be where it is, which is nonsense. Hence my illustration.

Let me fix that.

 

[JimRausch]

tarcrarc- here's another possible method to get your SG down that I've read about, but fortunately never had to try:
Brew another batch of a reasonably low OG- stout or anything else you are interested in. Probably the same yeast strains- so an Irish Red?, a Porter? Then when it's finished and packaged, dump the stalled batch on the complete yeast cake. Massive overpitch might get it kicking again.
Just had another thought- I've read posts about using amylase enzyme in similar cases where there probably was too many unfermentable sugars. Do a search if you're interested. Good Luck!

 

[MrHopScotch]

I would definitely vote on checking that thermometer. The recipe doesn't seem crazy to me either. 156 is a perfectly reasonable temperature and I regularly get beers mashed at that temperature down to 1.010 or less. If your thermometer was reading low and you actually mashed at 160+ I could absolutely see you ending up with a ton of unfermentable sugar.

 

[tootal]

Using the rule of thumb as mentioned, oats are still considered an adjunct. I looked up a basic oatmeal stout in Dave Millers book and put it in ProMash and he ends up with 81% Base two row and 8% Oat flakes.
Now I put the OP's recipe in, including the rice hulls, and got the percentages within .5%. I then deleted the rice hulls and rounded off I got:

56% Base 2 row
20% Oat flakes
7% Victory
7% 80L
7% Roasted Barley
3 % Chocolate

So with the 2 row and Victory you have 63% base malt. I understand that Oat flakes are fermentable but it still goes outside of the 70 % rule. I did brew an Imperial Oatmeal Cream Stout and I didn't use the 70% rule and the beer stopped around the same place and it was really bad! :cross:

That's the reason I suspected the recipe. Compared the Dave Miller's recipe you can see the stark difference in percentages.

Temperature, length of mash and mash ph could all be the problem except that you said you hit your numbers so all those are mute if your reading was accurate. That leaves fermentation temps and the health of the yeast.

At this point you might try some champagne yeast.?

 

[Calder]

At this point you might try some champagne yeast.?

I see a lot of people recommending this, but have yet to find someone reporting that it works.

I've never tried it, so it may work, but from everything I have read, it would seem to be a bad idea.

- Champagne yeast is a killer yeast, so once used, would probably make it harder to use an ale yeast after it.

- Most wine yeasts ferment only simple sugars, which are almost certainly already consumed. They can't break down the complex sugars, so will probably not do much. It is often used for priming high gravity beers, because it only works on the simple priming sugar and will not cause bottle bombs.

 

[tarcrarc]

First off..thanks for looking into/discussing this matter:

I checked the thermometer---it is dead on.

My Fermentation temp stayed the same without any swings (thanks to my Ranco).

The yeast was fresh and I made a huge starter, using 2 vials (wlp 007 and 001). On top of that this was only a 4.5 gallon batch into the fermentor.

The mash pH was 5.33 so that wasn't an issue.

As stated, I gave the wort about 1 minute of pure O2 and a minute shake.

I added nutrient to the end of the boil as well.

I had never started my fermentation as low as 62 degrees, but it seems others have done so with these yeast strains without issue.

 

[tarcrarc]

I think I'm going to risk it and do the following:

1. Harvest the yeast
2. Make the same batch again (less oats), this time mashing at 145
3. Pray for a much lower FG
4. Blend the 2 batches

Or should I do the above but throw in another vial of wlp 001?

 

[tootal]

Well the answer is obvious, make another beer and blend it cause you'll end up with MORE BEER!


Whatever you decide good luck with it and I hope it works out well for you!

Have a Happy New Year!:rockin: