Lactose in an Imperial Stout?

[TopFlatBrwr]

I'm brewing a chocolate raspberry imperial stout and was going to add lactose to recipe to get a higher FG and add a bit more sweetness to finished beer. I read in BYO that lactose doesn't mix well with imperial stouts. Has anyone else found this to be the case or know why I should keep lactose out of my Imperial stout recipe?

Here's an excerpt from the article:

The common misconception is that if a beer is a stout, it must be high in alcohol. Yet most, with the exception of imperial stouts, are actually in the 4–6% alcohol by volume (ABV) range. (Lancaster Milk Stout is 5.2%; Lefthand Milk Stout lands at 5.3% while Samuel Adams Cream Stout falls to 4.7%.) Higher gravity beers might not work well with the lactose, Christoffel says. Adding lactose will not change the alcohol content, only the beer’s character and “I wouldn’t recommend using it in an imperial stout recipe,” he says. “There will be a conflict of flavors. The imperial stout has a rich body to begin with. The Plato is high already so there will be some residual extract. It would make the beer a little too sweetish because of the starting gravity. I’d say your really good results are going to be with a stout that has a gravity between 14–16 °Plato (SG 1.056–1.064). I wouldn’t go much higher.”

 

[Beernik]

I have not made an imperial stout but I've made plenty of stouts. I think lactose would be a bad idea. I think you risk it ending up way to sweet.

However, the benefit of of a non-fermentable sugar is you can wait until bottling/kegging to add it.

Ferment it. See if you like the sweetness level. If you want more, add some, mix gently, and sample again.

 

[HopOnHops]

I would prefer to pick a less attenuative yeast, use a higher mash temp, and adjust the same pitch rate to get a higher FG. An imperial stout would tend to have a higher fg due to yeast attenuation eliminating the need to have lactose to increase fg unless you want it over 1.030

 

[TopFlatBrwr]

Adding in the lactose at bottling seems the way to go. I'll see where the beer ends up and add to taste when I bottle. I'm definitely mashing at 69C and fermenting low with wyeast 1084.