Sweet Stout: Ready to Keg? How much does Lactose effect FG?

[bearcamp]

I brewed the NB sweet stout on 12/4 was going to keg on 12/26 but gravity reading was 1.030 so I stirred the yeast up and let it go another week. I understand that ESB ale yeast likes to quit early. Today I am ready to keg again but gravity reading was 1.022. Again I stir up the yeast to get the fermentation back on.

My question is does the lactose add to the FG points. Meaning a normal brew would end up 1.012 but would adding lactose up the FG higher? I was expecting 1.012 - 1.010 FG.

Recipe:

8lb Marris Otter
.8 OZ Chocolate
.8 Debittered Black Malt
1lb Lactose - added during boil

Mash temp = 154
OG = 1.057
Yeast =WY 1968 - 2nd gen.

 

[hs0656]

I have brewed this exact beer before and I always have a sweet stout on nitrogen. The three times that I brewed this specific recipe from NB, my FG was 1.018 all three times. I always use neobrittania however that is stepped up from a slant.

 

[hs0656]

Since you're OG was 1.057, and FG is now at 1.022, I'd keg her up. You don't necessarily need the ABV to be super high. Mine usually ends at around 6%.

 

[Polboy]

lactose add 30 gravity points per gallon, if you are making 5gal batch so lactose should raise your SG by 6 points and because its not fermented by sach cerevisiae this 6 points will show up in your FG reading so if from grain bill without lactose you would expect 1.012 with lactose you should have 1.018, looks like yours little sweeter, im guessing 154 mash tem and rather low attenuation of 1968 has something to do with this

 

[bearcamp]

thanks for the responses. I'll give it another week in the fermentor and keg next week. I thought lactose would add points but didn't know how much. The sample tasted good. Another week shouldn't hurt.

As always HBT rocks!

 

[beergolf]

It is probably done. Lactose can make it finish high. 1.022 is fine for a sweet stout if the reading is stable for a few days.