Milk stouts, lactose, and gravity

[AQUILAS]

A few weeks back, I brewed my peanut butter milk stout recipe. I hit 10 points above the estimated OG of 1.066 and got 1.076. It's been 2 weeks in the primary and the SG as of today is 1.037. I seem to only have hit 50% attenuation, which is much lower than my usual with starters. I'm going to take it out of the ferm chamber this week (gotta put my belgian wit in it tomorrow) and have it at room temp, so the temperature bump should help.

There's a real nice PB aroma and a nice PB flavor note. Sitting here after finishing the sample, I feel like I just had some peanut butter cups. There's also an alcohol smell to it, but it's not hot in the mouth. Not sure if this is a bad thing, but since it isn't burning on the way down, I'm not gonna worry.

My question is since I hit 10 points above the estimated OG, is it right to assume that my FG will be about 10 points higher than the estimated FG? Or do milk stouts generally have higher than expected SG because of the unfermentable lactose in it (I used a pound).

 

[RM-MN]

I can't see your recipe, the notice I get is that it has been made private or deleted so I don't know where you should be based on the recipe but that sounds waaay too high for a FG, like it might if you were using a refractometer instead of hydrometer. If you are using a hydrometer, verify that it reads 1.000 in plain water and then try it again in the wort. If it still reads 1.037, I'd expect a stuck ferment. Warming it might help get it going again.

 

[specharka]

My question is since I hit 10 points above the estimated OG, is it right to assume that my FG will be about 10 points higher than the estimated FG? Or do milk stouts generally have higher than expected SG because of the unfermentable lactose in it (I used a pound).

No and yes. The unfermentable lactose will not be able to reduce. Lactose contributes approximately 35 points per pound per gallon, so your OG and FG will reflect that unfermentable sugar.

Still, 1.037 seems a little high for that starting gravity. What was your brewing process? The link doesn't appear to work.

 

[AQUILAS]

I can't see your recipe, the notice I get is that it has been made private or deleted so I don't know where you should be based on the recipe but that sounds waaay too high for a FG, like it might if you were using a refractometer instead of hydrometer. If you are using a hydrometer, verify that it reads 1.000 in plain water and then try it again in the wort. If it still reads 1.037, I'd expect a stuck ferment. Warming it might help get it going again.

No and yes. The unfermentable lactose will not be able to reduce. Lactose contributes approximately 35 points per pound per gallon, so your OG and FG will reflect that unfermentable sugar.

Still, 1.037 seems a little high for that starting gravity. What was your brewing process? The link doesn't appear to work.

Sorry about the recipe, I just un-privated it.

Hydrometer is calibrated. After I took the sample, I figured I'd try and use it in distilled water. 1.000 on the dot.

EDIT: forgot to include my brew process. I do full volume BIAB/mash in a cooler. About 9gal of water in the cooler, dough in, stir, and leave for an hour. Then the standard drain into kettle, boil, aerate, pitch yeast, and store in fermchamber at about 65F.

 

[Calder]

3 lbs of specialty grains + 1 lb lactose is a lot, and should result in a very high FG, but 1.037 is extremely high. If you had said you were somewhere around 1.025, I would have said you were done.

What mash temp?

Have you checked your mash thermometer? Check reading in ice water and boiling water.

1.076 seems pretty reasonable for that grain bill.