Fermentation stopped? Partial mash recipe...long chain sugars?

HI,
I am brewed a IPA partial mash recipe (my 2nd partial mash), here are the fermentables.

7 gal LME
1# DME
1.5# 2-Row grain
.75# other grains

I partial mashed, a bit high I think, at about 155-160.

OG - 1.092
Fermentation started great, airlock activity in >12 hours, put on a blowoff tube and by the end of the day krausen was happily pumping through the tube.

The next day I had no airlock activity. Checked the SG that evening as was at 1.031, that was 4 days ago and I remain at 1.031.

Where I ferment is about 67 degrees. I moved the bucket upstairs yesterday after work to a room that is about 71 degrees.

Right now I am a bit over 8%abv but with only about 66% attenuation.
Could this have anything to do with the higher mash temps and long chain sugars? I would not think so with the amount of LME and DME that I used.

While it has only been fermenting for about a week I plan to leave it for at least 2 more weeks then move to a secondary and dry hop for a week.

Do I care about trying to kick start the yeast?
Anything I should change about my current plan?
THANKS,
Lakedawgs

I'm assuming that's 7# LME, not gallons .

The higher mash could result in a bit of lost attenuation, but since it was a small portion of the overall recipe, it's probably not the reason. Also, bear in mind that the extracts themselves have a portion of unfermentables in them as well.

What yeast did you use and what was your expected FG? I'd definitely give it at least two more weeks, regardless, as with a beer that big the yeast will get sluggish even while they continue to work. Check again in another week to see if it's still stuck and then you can weigh your options accordingly.

7#, 7gallon.............hmmmm, you are correct

Safale US-05, Dry Ale Yeast
73% attenuation would put me at about 1.025FG. I would like to get my attenuation in the 70s at least.

I am definitely planning at least 7-10 more days in the fermenter and if it does not move I will likely secondary and dry hop for a few days.

lakedawgs said:

7#, 7gallon.............hmmmm, you are correct

Safale US-05, Dry Ale Yeast
73% attenuation would put me at about 1.025FG. I would like to get my attenuation in the 70s at least.

I am definitely planning at least 7-10 more days in the fermenter and if it does not move I will likely secondary and dry hop for a few days.

Click to expand...

How many packages of So5 did you use for the 1.092 OG beer?

I only used 1 and this was a concern. But with the krausen pumping out of the blow off tube for 6+ hours the day after brewing that meant I had a ton of yeast cooking away.......correct?
I am a big time newbie but I thought that was correct.

I have yeast nutrient and yeast energizer, either of those useful? I could also run out in the morning and get another pack of yeast to pitch if that would help.

Any thoughts would be appreciated.

lakedawgs said:

I only used 1 and this was a concern. But with the krausen pumping out of the blow off tube for 6+ hours the day after brewing that meant I had a ton of yeast cooking away.......correct?
I am a big time newbie but I thought that was correct.

I have yeast nutrient and yeast energizer, either of those useful? I could also run out in the morning and get another pack of yeast to pitch if that would help.

Any thoughts would be appreciated.

Click to expand...

Grossly under pitched, especially if you didn't properly rehydrate it. I had a 1.092 Barley Wine get down to 1.015 in 15 days with 2 packs of rehydrated US-05.
I'd let it be for at least another month and see what it does. With that big of a beer a month or 2 in the fermenter isn't going to do anything but good.

Bob

OK, that sounds good. I am in no rush on this one.
I do realize now that I underpitched for a big beer.
But help me understand. When I had a krausen coming out of the fermenter I though that meant I had an overabundance of yeast, is that not true or does that not mean anything?
I just rehydrated the yeast in a 1/2 cup of water for an hour or two before pitching.
Thanks

Large amounts of krausen indicates vigourous fermentation, not healthy yeast. It sounds like you left you yeast in the warm water for too long resulting in a loss of yeast health. I have never used Safale products, but both Danstar and Lallemand recommend pitching right after hydrating for 15 minutes. 1-2 hours is way too long.

To attenuate those last sugars you would have to make a starter with 1 pack of S-05 with in 1L water with 100g DME. Pitch the starter at high krausen and it should finish the job if it is too sweet for you as it is.

BobBailey said:

Grossly under pitched, especially if you didn't properly rehydrate it. I had a 1.092 Barley Wine get down to 1.015 in 15 days with 2 packs of rehydrated US-05.
I'd let it be for at least another month and see what it does. With that big of a beer a month or 2 in the fermenter isn't going to do anything but good.

Bob

Click to expand...

Woah! I just went back and reread your original post. Looking at the malt/grain bill I see about 1.071 OG for 5 gallons of wort. Those fermentables would only produce an OG of 1.092 in a little less than 4 gallons.

Did you take the OG reading before topping off your fermenter or just ferment under 4 gallons?

If you took your OG reading and then topped off with water to 5 gallons, you started with an OG around 1.071 and attenuation is really in the toilet. If that's the case, I'd pitch another packet of rehydrated yeast rather than playing the waiting game.

Bob

No, it was a 5 gallon batch. Confirmed by my brew pot scale and the fermentation bucket scale.
While I understand I way underpitched on my yeast, I was wanting a bigger beer, that's why I added the 1#DME.
Not sure I understand why my OG showed so high if you calculated it to be at 1.071???

I stopped by my LHBS today and they suggested I pitch another pack of yeast, which I did after hydrating. I figure there is no harm in that. It will be in the primary for another 3 wks and then moved to a secondary to dry hop for a few days.

If you did a partial boil and topped off with water you could have gotten a bad hydrometer reading because the wort & water weren't mixed well. Other than that, I guess your hydrometer could be off or it stuck to the side of the tube and you just got a bad reading.

As an example, if you used a kit and added 1 lb. of DME to a 5 gallon batch you gained about 8.8 points, so if the kit was supposed to yield an OG of 1.062 a pound of LME would up it to about 1.071.

You did the right thing by repitching. Sorry I didn't catch the malt/grain bill part of your original post before my first reply.

Bob