Stout FG not dropping

I brewed a milk stout 2 weeks ago, the OG was 1.060 and the FG has only dropped down to 1.030. I mashed at 156, so not that high, and only added 1/2 lb. of lactose. I pitched with Nottingham, which I've always gotten 75% attenuation before. Should I repitch another packet? Here's the recipe:

10-28-2007 Milk Stout


Grain/Extract/Sugar

% Amount Name Origin Potential SRM
-----------------------------------------------------------------------------
54.4 7.00 lbs. Maris Otter Great Britain 1.038 3
7.8 1.00 lbs. Wheat Malt America 1.038 2
7.8 1.00 lbs. Flaked Oats America 1.033 2
3.9 0.50 lbs. Chocolate Malt America 1.029 170
7.8 1.00 lbs. Coffee Malt 1.030 150
3.9 0.50 lbs. Roasted Barley America 1.028 450
7.8 1.00 lbs. Brown Malt Great Britain 1.032 70
2.9 0.38 lbs. Cara-Pils Dextrine Malt 1.033 2
3.9 0.50 lbs. Milk Sugar Generic 1.030 0

Potential represented as SG per pound per gallon.


Hops

Amount Name Form Alpha IBU Boil Time
-----------------------------------------------------------------------------
1.00 oz. Fuggle Pellet 5.00 23.0 60 min.
0.50 oz. Saazer Pellet 4.30 5.0 30 min.


Yeast
-----
Nottingham





Mash Schedule
-------------

Mash Type: Single Step
Heat Type: Direct

Grain Lbs: 12.38
Water Qts: 18.56 - Before Additional Infusions
Water Gal: 4.64 - Before Additional Infusions

Qts Water Per Lbs Grain: 1.50

Tun Thermal Mass: 0.10
Grain Temp: 80 F

Dough In Temp: 169 Time: 0
Saccharification Rest Temp: 156 Time: 0
Mash-out Rest Temp: 0 Time: 0
Sparge Temp: 0 Time: 0

Runnings Stopped At: 1.010 SG 2.56 Plato


Total Mash Volume Gal: 5.63 - After Additional Infusions

All temperature measurements are degrees Fahrenheit.

Anyone? Bueller? I know it sounds like a noob problem, but I've never had such low attenuation before.

The oats and cara-pils would also add to the unfermentables but I wouldn't think they'd go that high, even with all that lactose. Have you tried swirling the fermenter to rouse the yeast?

Pitch another packed of rehydrated yeast, rouse the fermenter and raise the temperature. If it drops around 65%A then it will probably be done, since you have lots of unfermentable sugars and a high mash temperature.

I started fermentation around 65, since then I've warmed it up to room temp for a week, plus roused the carboy multiple times. I guess I'll pitch another packet, and if it doesn't drop, I'll forgo adding any more lactose since it's pretty sweet as it is.

You may be done.

I couldn't find the points per pound for lactose but if you assume it is similar to sugar it would be about 45, that gives you about 4.5 points for 5g. Subtract that from 1.030 and you are at 1.025. Given the relatively high mash temp and the other components that will add unfermentables your yeast may have done all they could.

GT

My sources say that half a pound of lactose in 5 gallons will contribute 4 SG points...that puts you at 54% attenuation. I guess the additional yeast is you best bet. How warm have you gotten it? Maybe up to the mid 70s would get things moving again.

A 156F mash is at the high end and you have 10-11 points of unfermentables from the specialty grains, plus 5 points from the lactose. I think your FG is reasonable.

I've gotten it up to the low 70's probably. I'll pitch some more yeast today, and if it doesn't drop by next weekend, I'll just keg it up. Thanks everyone.

Yea, good chance you are done with the lactose, specialty grains and mash temp. LIke everyone else had said, pitch some more yeast and see if it drops, if not, your done

+1 (I know, I pretty much repeated what's been said)

Professor Frink said:

I brewed a milk stout 2 weeks ago, the OG was 1.060 and the FG has only dropped down to 1.030. I mashed at 156, so not that high, and only added 1/2 lb. of lactose. I pitched with Nottingham, which I've always gotten 75% attenuation before. Should I repitch another packet? Here's the recipe:

Click to expand...

You should have had 1.030 after 4-5 days. This sux. It's not going to drop much lower IMO. To many unfermentables. The yeast probably crapped out. I suggest using twice as much 2-row next time.

To fix THIS brew, re-oxygenate, and boil 3lb pale liquid malt extract, or mash 5lb 2-row, then chill and add. 4 days later, I hope the gravity will be in shape.