Firstly - I agree with what others have said about this being better to save for after you've got a few brews under your belt and feel more comfortable with yeast management, sanitation, etc. That being said – It’ll be worth your time to cut your teeth on the clean base beer before pitching the Brettanomyces. You’ll still end up with a solid saison. This is one of my favorite beers of all time, and a recipe I have been working on for a while; It’s actually next on my list. I live about a mile and a half from Allagash and am pretty spoiled with having access to their smaller batches (this is important in a moment). Here is what I’ve come up with so far.
Allagash lists the OG as 1.063 and an abv of 7.4% (this means a target FG of about 1.006). We know that they use a blend of 2-row, pilsner, and ‘caramel malt’. This is enough to determine a reasonable grain bill:
Assuming a 5g all-grain batch at ~70% efficiency (can convert to extract later if needed)
o 10# of American 2-row
o 3# of Belgian Pilsner
o 0.5# Belgian Carapils
This grain bill will give us the correct OG at 70% efficiency, and an SRM of about 4.5 which is in the ballpark BUT I’ll probably boil for 90 minutes which will darken the wort a bit more, allow for some sweeter flavors to come through the dryness of this beer.
EDIT: You could replace the 2-row with non-hopped Light DME and the Pilsner with either the same, or non-hopped Pilsen DME. Make sure you enter the replacements into a brewing calculator like brewers friend to tarted the 1.063 OG. You can steep the Carapils or possibly 0.5# cara20 for more color. Someone might be able to better help with this conversion.
Allagash also lists their hops as Glacier and Tettnang but they do not list the IBU. It’s been a couple months since I picked up a bottle but I would guess 40-50 IBU. I’m thinking a bittering charge of either hop variety, as well as a 30 minute and 10-minute addition. They do dry-hop with Glacier (I’d say probably 2oz for a 5 gal batch.
Now here is why living near the brewery is helpful – Confluence is fermented with their house yeast and their house Brett strain (they had it cultured from an accidental infection in the first batch of Interlude). Neither the house yeast or Brett strain are commercially available. A few times a year they release a beer called Little Brett at limited distribution. This is fermented 100% with their house strain. I cultured some dregs from those bottles and as a result have a reliable source of their house Brett. Now, the way they pitch it is just as, if not more, important that their exact strain. In the book American Sour Beers (by Michael Tonsmire aka The Mad Fermentationist) the author outlines the fermentation process for Confluence – Rather than pitching a primary strain and then the Brett afterwards, they pitch a very large and healthy dose of Brett at the same time as their house yeast. This is what results in the specific balance in fruity/funky flavors from the Brett. They ferment it out for about 9 months before dry-hopping and packaging. For this beer I would recommend using a commercial pitch of B. clausenii for similar flavors if you don’t have access to one of their 100% Brett beers. Make sure that you use a big pitch of Brett and a saison strain that you like (Wyeast 3711 is VERY easy to work with, but I love the flavors from 3724)
That’s what I’ve got so far and I recommend giving it a shot! Try it with just clean saison yeast first until you gain a bit more experience. This will help keep other batches you brew from getting contaminated, help you dial in saison brewing, and nail the base recipe before investing the money and 9-12 months of your time. I plan to do something similar – I brew 10 gallon batches so I am going to split it into two 5gallon fermenters and half will get the Brett, and half will stay as a clean, confluence inspired saison.