Stuck Fermentation at 1.042

[Acumen]

Brewed this stout 2 1/2 weeks ago. I was racking it to a secondary to clear out hops/trub floating around. Took a reading and I am still at 1.042?! I am expecting 1.010 - 1.012
It tastes great, but my OG was only a few points higher ~1.046.

7# Pale
3# Roasted
2# Flaked Barley

30 min 1oz Northern Brewers
5 min 1oz Kent Goldings

1 pack Safale - 04

60 min mash
60 min boil

Fermentation started fine. Within 12 hours it was bubbling away. Lasted under 2 days, but I have read that was normal for 04.

When I read the gravity, I made sure to swirl the trub and dump in a good amount to the secondary to get plenty of yeast. The only thing I could think to do was aerate, so I gave it a good rocking... I am not worried about oxegenation at this point because it is not close to being fermented. It has been sitting in my basement, where the temp is 60-70. There was a heat wave here where it hit 87 outside, but I don't think it really could have brought the temp up in the basement over 75, and that was after the fermentation appeared to be over.

Anyway I'm confused about the whole thing, and would appreciate any insight.

 

[Kuglehaus]

1.) Did you temp correct the OG?
2.) Did you temp correct the FG?
3.) Are you able to validate the accuracy of your hydrometer with distilled water (to check that it reads 1.000)
4.) What was your Mash Temp (are you confident that your therm was accurate?)

 

[Acumen]

OG and FG were read at ~65.
Hydrometer reads correctly.
Mash temp was ~162, Sparge 165-175.
Thermometer reads correctly.

 

[Reno_eNVy]

Yeah, I check it out on beersmith. It's saying your OG should be roughly 1.058. Was it near there? If not, then I think you may be reading your hydrometer wrong, as Kugelhaus said. Your hydrometer is probably set to read correctly at 60F

So being stuck at 1.042 with a start of 1.058 is either caused by a huge problem with your brewing procedures or misinterpreted readings.

Either way, I'd say give it time. If it's only been two days then you just need to RDWHAHB my friend. I'd give a stout 4 weeks, personally.... but then again, I do that with most of my brews.

 

[Reno_eNVy]

Mash temp was ~162

Heh, sorry late response. Um, that's kinda high. You're going to have a lot of unfermentable dextrins in your beer.... maybe why it's stuck. 154-158 is appropriate for a stout

 

[Acumen]

I just went back and checked my notes. I do a 2 pot boil and the OG reading was from the weaker pot which was a detail I forgot since I normally take it from the full carboy. The overall OG may very well have been ~1.06 since I have been getting upwards of 80% efficiency.

I am still expecting a FG well under 1.02 though.

If the yeast don't get roused by what I did, I may try dumping in a starter of Wyeast Irish Ale. Does that sound like the right move?

 

[Kuglehaus]

If it's the mash temp, you may need to add some fermentable sugars...dme/lme to move the needle. 162 is a very high temp and will lead to a ton of unfermentables, so the delta in SG/OG actually sounds right... You might have a sweet weak beer, or add some fermentables and some hop tea and head for big beer land, you have a wonderful sweet base to balance heavy alcohol content and bitter....

 

[Acumen]

Interesting. I have not been paying as close attention to my mash temps as I should have been. I was aware that different temps were used for different rests and all, but thought that was a more advanced art then I needed at this point. I am still getting a bearing on the different malts, hops and yeasts.

I have been kind of winging the temperature of my mash and sparge up to this point, with the strike ~165-170 for mash and ~170-180 for sparge. Up until this stout I have not had any issues, but now that I have damaged a brew, I will definately do due dilligence on my mash/sparge temps.

How much DME do you think would be appropriate?
What about using dextrose instead? (I already have it, and no DME)

 

[joety]

Agree on the mash temps. I think you normally want to be in the 148-158 range, and that is a cavernous range, with only the sweetest/maltiest beers mashed near 158.

I brewed a porter recently that started at 1091 and was at 1025 after a week (nottingham). Thought I was done, but when I transfered to secondary two weeks later to oak it, I was down to 1021, which I was a lot more happy about.

That one was mashed at 154, which is as high as I've ever mashed anything.

 

[Kuglehaus]

I think the SG of Dextrose in 1.045 per another thread. So if you are doing a 5 gallon batch, you're looking at 5lbs to get to a gross SG of about 1.1... 9% abv will offset the sweetness you have.. But I would add, ferment...repeat and taste.. you're the best judge.

 

[Acumen]

Thanks for the help everyone.

I will slowly add dextrose to bump up the ABV to taste.

The good thing to come out of this is that I have had my eyes opened to the effects of varying mash temps and will not ignore it from now on.

One follow up question, what will the differences be in worts where one has the main sacc rest at 153 the whole time, and one where it is stepped from say 144 to 158?

 

[Kuglehaus]

Perhaps the decoction info will assist you.. I'm out of my league on that question.

 

[thedude123]

Was your mash temp 162 or was your strike water for the mash 162?

I don't think a decoction mash would be appropriate for a stout.

 

[Acumen]

Well normally I would aim for a strike around there or a little higher, but on the day in question I was hosting a brew party. There were maybe 8 completely inexperienced brewers and about 4 cases of beer. When it comes down to it, the mash may very well have been 162 since that what my notes seem to indicate and I wasn't aware until this thread of the problems overshooting a mash temp causes and would have done nothing to try and lower it even if I had seen it.

 

[thedude123]

Normally if your strike was that temp, depending on the temperature of the grain, the mash will be in the low 150's