[AmandaK]

14 lbs of marris otter
1 lb biscut
1 lb of crystal 60
1 lb of chocolate malt
1 lb of special b
1/4 lb of black patent
1/4 lb of roasted barley
using Belgium abbey 2

Not  good yeast choice for an RIS.  it will make it taste like a Belgian beer, not RIS.  You've also got quite a bit of crystal in there.  Personally, I don't see how you're gonna hit close to 10% with that grist.

Agreed on all fronts, Denny. I know this is an equipment/efficiency question, but that recipe will not make a RIS.  Even if you did get your normal max efficiency, 18.5lbs of base grain will only yield an OG of 1.088 (I don't feel like accounting for the lower potential of roasted malts right now) - which isn't a 10% beer until you get down to around 1.010 FG, all of which is unlikely with the amount of crystal malts in your friend's recipe.

[denny]

which isn't a 10% beer until you get down to around 1.010 FG, all of which is unlikely with the amount of crystal malts in your friend's recipe.

Not to mention that an FG that low isn't desirable in a beer like that.

[AmandaK]

which isn't a 10% beer until you get down to around 1.010 FG, all of which is unlikely with the amount of crystal malts in your friend's recipe.

Not to mention that an FG that low isn't desirable in a beer like that.

Well, yes. But I didn't want to ramble. 

OP - we are just trying to help you (and your friend) make the best beer possible. I hope that our posts can aid in that.

[Iliff Ave]

14 lbs of marris otter
1 lb biscut
1 lb of crystal 60
1 lb of chocolate malt
1 lb of special b
1/4 lb of black patent
1/4 lb of roasted barley
using Belgium abbey 2

Not  good yeast choice for an RIS.  it will make it taste like a Belgian beer, not RIS.  You've also got quite a bit of crystal in there.  Personally, I don't see how you're gonna hit close to 10% with that grist.

Out of curiousity, is 5.4% crystal malt really too much for this?

[denny]

Well, yes. But I didn't want to ramble. 

That's why I'm here! 

OP - we are just trying to help you (and your friend) make the best beer possible. I hope that our posts can aid in that.

Absolutely!

[denny]

Out of curiousity, is 5.4% crystal malt really too much for this?

Maybe not, but it's something to think about in a high OG beer with no sugar.

[twopumpsandimsorry]

I do appreciate the feedback. It's likely that dme will be in the picture. Will likely be mashing low and long and possible sparging with some of the wort from the initial runoff. Am interested to learn more about the effect of crystal to fermentation. Why would a pound in a 18.5 lb of grist make a dif.

[AmandaK]

Am interested to learn more about the effect of crystal to fermentation. Why would a pound in a 18.5 lb of grist make a dif.

A pound of crystal, no, but a pound of crystal, a pound of chocolate, a pound of Special B and a half pound of highly roasted malts will begin to limit the amount of attenuation you can get.

[redbeerman]

Am interested to learn more about the effect of crystal to fermentation. Why would a pound in a 18.5 lb of grist make a dif.

A pound of crystal, no, but a pound of crystal, a pound of chocolate, a pound of Special B and a half pound of highly roasted malts will begin to limit the amount of attenuation you can get.

Don't forget the biscuit!  Like Amanda said, none of the specialty malts will attenuate like the base malt.  An RIS should be thick and chewy IMHO with a bunch of roast character and fairly high bitterness to offset the sweetness from a (usually) high FG.  As was said as well, a Belgian yeast strain will not give you the character you desire, I don't think.

[twopumpsandimsorry]

Makes sense with all of the speciality malts. Like I said just the assistant on this one, it's a frankebrew for sure. Won't really resemble a RIS.

[Joe Sr.]

I know it's not part of your question but don't forget aeration and a big pitch of yeast.  These are especially critical for a big beer IMO.

[reverseapachemaster]

Every comment here is really useful advice for you and your friend. You can mash and sparge with all the technique in the world but that recipe is not going to produce a quality imperial stout. Your friend should start over on the recipe for all the reasons given above.

One thing mentioned that I haven't seen anybody address is the idea of sparging with your runnings. That is not a good idea. The objective of sparging is to divorce the sugars from the grain. By putting the wort back in the mash tun you are doing the opposite of what you want to happen.

[bluesman]

If you decide to stick with that recipe, you are definitely going to want to mash low and long to break down as many of those sugars as possible. If you cut back a bit on the Biscuit and C60 a bit, and add some sugar you'll render a more fermentable wort (higher starting OG), hence a higher finishing ABV.

Also depends on what your hoping for in the finished beer. Do you want a very thick chewy stout OR a more drinkable version at 10% ABV?

[drjones]

re. mashing process.  I don't see a real advantage of mashing in the kettle.  While I do this myself in a small 8 gallon pot with a false bottom, it requires an extra level of temperature monitoring and stirring.  Why not do a simple batch sparge in the insulated cooler?  I assume it is big enough to handle the grain bill. 
I agree with everyone else regarding the addition of sugar - at least a pound near the end of the boil would help.  And which chocolate variety?  Pale or dark?  That will have a significant flavor impact as well.

[twopumpsandimsorry]

We managed to get 1.112 without additions. We mashed half of the grains the night before and used the wort from that to mash the second batch, sparged with h20  and boiled. Will see what the result is, if the beer is no good then it was more then worth it for the learning experience.