The first beer will get all of the dense first runnings, so it starts pre-boil at a high gravity and doesn't require an excessively long boil to concentrate the sugars. After the wort for the big beer is collected the mash in infused with sparge water and the wort for a second beer is drained. The gravity of the wort falls precipitously with each infusion, with the second beer usually in the sessionable range and the third down towards "table" strength.
The lower gravity beers often take a backseat to the big beer, but there is some room to augment their fermentables. You can cap the mash to add additional color/flavors (for example I made a black IPA from the second runnings from an overclocked Pliny the Elder clone by adding Carafa to the mash after draining the first runnings). You can also cheat, for this second runnings saison I added some malt extract to the boil to help boost the gravity (a flavorful sugar is another option).
The initial mash temperature will set the fermentability of all of the wort, this will need to be a compromise (although you might try infusing the sparge water at a temperature that would allow for good beta-amylase activity [~145] with additional base malt in order to increase the fermentability of the second/third beer), the auxiliary beer often come out a bit thinner than you might expect, given the OG/FG, so the extra effort to increase attenuation may not be worth the effort.
With the mostly pilsner malt grist of my Calvados Sour Tripel, the best option I could think of for the second runnings was a low gravity saison. The problem was that I wanted to mash hot for the tripel to ensure there were dextrins for the microbes to consume over the long slow souring process, but I like my saisons dry. To try to overcome this conundrum I opted to combine the notoriously temperamental Dupont strain with Brett claussenii for primary fermentation. This is an idea I stole from Bullfrog Brewing, whose Busted Lawnmower is one of my favorite American examples of the style (rustic, dry, hoppy, deceptively drinkable).
For the hopping I went with a similar strategy to the one I took with the Hoppy French Saison I brewed last year. This recipe is not quite as hoppy/bitter, but all of that spicy Saaz should complement the peppery phenols created by the yeast strains. I wanted to keep this one free of actual spices to let the fermentation character take the lead. After a few weeks fermenting slowly, with a heating pad to keep it warm, I racked the beer to secondary and pitched the yeast cake into the third in our annual series of spiced dark fruit saisons (this year Alex and I went with fig, buckwheat honey, and anise).
Bretted Petite Saison
Batch Size (Gal): 5.25
Total Grain (Lbs): 22.48
Anticipated OG: 1.046
Anticipated SRM: 6.4
Anticipated IBU: 30.2
Brewhouse Efficiency: 24 % (67% including the first runnings)
Wort Boil Time: 90 Minutes
53.4% 12.00 lbs. German Pilsener
36.7% 8.25 lbs. French Pilsener
4.4% 1.00 lbs. Flaked Wheat
4.4% 1.00 lbs. Light DME
1.0% 0.23 lbs. CaraPils
2.00 oz. Czech Saaz (Pellet, 3.50% AA) @ 45 min.
0.50 oz. Czech Saaz (Pellet, 3.50% AA) @ 15 min.
0.50 oz. Czech Saaz (Pellet, 3.50% AA) @ 5 min.
0.50 Tsp Yeast Nutrient Other @ 15 min.
White Labs WLP565 Belgian Saison I
White Labs WLP645 Brettanomyces claussenii
Profile: Washington DC
Sacch Rest 45 min @ 154
Mash Out 10 min @ 167
Brewed 10/31/10 by myself
Second runnings from Calvados Sour Tripel.
Sparged with ~7 gallons of 170 degree water and ran off 7.5 gallons of wort for the saison. Added 1 lb of Light DME to bring the gravity up.
Both beers were lower gravity than expected.
Chilled to ~85, racked to a better bottle. 3 hours later pitched one tube each White Labs Brett C and White Labs Saison and placed on a heating pad set to low. Ambient temp ~63 F.
Turned off heating pad after one week, krausen gone, but still looks very yeasty/cloudy.
11/11/10 Small pellicle formed. Racked to secondary, gravity still 1.020 (counting on the Brett to get it down below 1.010). Tastes good, nice spicy character, some hop bitterness, still too thick/sweet. Turned the heating pad back on to try to get the yeast moving.
11/18/10 Turned heating pad off, still low 60s ambient.
4/9/11 Kegged with 3.75 oz of cane sugar for natural carbonation. Maybe I'll add dry hops after seeing how it is without. Only made it down to 1.008 (82% AA, 5% ABV), not quite as dry as I was hoping for.
7/13/11 Solid beer, although a bit funkier and a touch sweeter than I had wanted. Next time mash cooler and maybe hold off on the Brett until a few days into fermentation.
7/18/11 Added 40 g of Australian Summer Saaz pellets in a baggie with marbles to the half filled keg to add a bit more fruit and freshness since the Brett is stronger than expected.
Bullfrog's Busted Lawnmower: A complex combination of citrus fruits, peppery spice and the funk-a-licious Brettanomyces Clausenii dominate the nose and palette of this Belgian-inspired ale. Wonderfully effervescent, this is the real lawnmower beer of Belgium. 7.5% ABV