Here's my stab at it, with my own personalized tweaks -- I am anti-Sinamar so I'll use Carafa III, and I love Special B so I'm matching the Carafa 1-for-1 with that. I have checked every reference, run every number, and I think this recipe will turn out really, really, REALLY close to the real thing:
Dave's Rochefort 6 Clone
5 gallons
Brewhouse efficiency assumed 82%
OG=1.072
FG~1.013
IBU=18
SRM=19.4
ABV=7.7%
8.625 lb Belgian pilsner
1.1 lb flaked wheat
0.25 lb Carafa III
0.25 lb Special B
1.5 lb dark brown candy sugar (reserve for late primary, not for initial kettle)
1.5 oz Hallertau (3.5% alpha, 60 minutes)
1 oz Styrian Golding (4.2% alpha, 5 minutes)
0.1 oz coriander (5 minutes)
Wyeast 1762 Abbey Ale II
Assumed moderate hardness tap water with addition of calcium chloride to hit 60 ppm calcium, and phosphoric or other acid to hit mash pH 5.4. AFTER the mash, add sufficient baking soda to bring carbonate up to 240 ppm. (For me and my water, this is 0.75 tsp CaCl2, 2 g dry acid, and 0.67 tsp baking soda -- YMMV).
Mash at 145 deg F for 40 minutes. Then step up to 165 deg F for 20 minutes (sacch, not mashout). Reserve the brown sugar until late in primary, do not add in the initial kettle. Make starter as desired and begin ferment at 68 F, try to hold there a couple days, then on day 3 or 4 allow to free rise into the low 70s. Also then on day 4, boil up the brown sugar in a little water, cool, and add to primary. On about day 7, check gravity and rack to secondary for another 3 days, keeping warm (do NOT cold crash at all, keep warm all the time). Bottle or keg when ready, carbonate on the high end, then keep warm about 73 F for 10 days prior to cellaring. Cellar for 6 weeks before drinking unless it tastes too awesome before then.
If anyone brews this, please, please, do a side by side vs. the real thing, and let me know how close it comes, I'd love to hear your experiences.
Cheers.