Hibiscus Sour on Oak

Today I'm doing a rare evening brew session. I don't do too many of these because it usually results in cleaning pots at midnight...something that isn't real high on my list of favorite things to do. I'm excited to get started on this beer though, so I'm just going,with it.

I'm starting the first of several experimental sour beers based on the well-publicized grain bills used by The Rare Barrel. The Rare Barrel essentially has three different base beers, a golden, a red, and a bruin (brown). They'll take these base beers and age them in different barrels and/or add adjuncts in secondary to end up with a variety of beers. If you google Rare Barrel Base Recipes, it's pretty easy to find them. Additionally, Jay Goodwin has freely provided info on several episodes of The BN's Sour Hour. The grain bills cited below were found on the Milk the Funk Wiki:

Golden Recipe

12° Plato (1.048 SG)
70% Base Malt (any type; probably Belgian Pilsner)
12% Malted Wheat
6% Rolled Oats
6% Spelt Malt (substitute wheat if you can't procure spelt)
6% Special Aromatic (specifically Franco-Belges; substitute with Vienna or Light Munich)

 Red Recipe

14° Plato (1.057 SG)
70% Base Malt (any type; probably Belgian Pilsner)
12% Malted Wheat
4.5% Rolled Oats
4.5% Spelt Malt (substitute wheat if you can't procure spelt)
4.5% Special Aromatic (specifically Franco-Belges; substitute with Vienna or Light Munich)
4.5% Crystal 60
Use de-husked black (Carafa II or III) to adjust color to you liking; ~1%

 Bruin Recipe

16° Plato (1.065 SG)
70% Base Malt (any type; probably Belgian Pilsner)
12% Malted Wheat
3.6% Rolled Oats
3.6% Spelt Malt (substitute wheat if you can't procure spelt)
3.6% Special Aromatic (specifically Franco-Belges; substitute with Vienna or Light Munich)
3.6% Crystal 60
3.6% Chocolate
Use de-husked black (Carafa II or III) to adjust color to you liking; ~1%

The beer I'm making today is based on the Golden Recipe above. I will be adding dried hibiscus flowers after fermentation. I've never used hibiscus before but they're said to give a slight tart berry-like character and tons of deep red color to a beer. For yeast, I'm going with a clean primary followed by dregs cultured from Jester King's Petite Prince. SO-4 should leave some sugars behind for whatever is in the JK dregs.

A note on the malts, it may be hard to find Spelt and Special Aromatic. Spelt is an heirloom wheat variety. Special Aromatic is said to be different than both Special B and Aromatic malt. I had to special order both from the guys at Salt City, but you could make substitutions as noted above. Here's the recipe as I made it:

5.75 # Weyermann Pilsner
1.00 # Weyermann Malted Wheat
0.50 # Rolled Oats
0.50 # Best Malz Spelt Malt
0.50 # Franco-Belges Special Aromatic
1-2 handfuls of rice hulls
7g U.S. Goldings (60 min)
7g Aged Hops (60 min)
Safale S-04 (Primary)
Jester King Petite Prince (Secondary)
3.0 oz Dried Hibiscus Flowers (Secondary) - TBD, either dry hopped or made into a tea
French oak, Medium+ toast for aging

Mash at 150F, 90 minute boil, primary ferment at 65F, secondary at room temp

Update 10/7/2015
Primary fermentation seems to have wrapped up and the yeast have dropped out for the most part. I tasted a sample from the Petite Prince dregs starter and it tastes amazing. I'll probably let this go until the weekend then rack to secondary and pitch the dregs.

Update 10/9/2015
I racked to secondary tonight and pitched the JK dregs.

Update 10/27/2015
Pulled a sample tonight. Aroma is pretty clean, not much funk yet. There's a subtle tartness starting to develop but at this point I'd call it tangy rather than tart or sour. I didn't bother taking a pH reading yet. I think this beer is headed in the right direction but it's probably going to take a while to mature. I'll have to monitor the sourness and make sure it's progressing. Worst case, I'll drop in some of my house sour blend...I think it's capable of souring anything. If you brew this beer, please take note of Jerad's comment below:

I contacted Jay Goodwin a while back and he mentioned that with these grain bills, they mash at 148 when doing 100% brett primaries and 155 with sacc in primary followed by brett in secondary.

Update 11/13/2015
Checked the pH today and it's down to 3.41. Sourness is much more noticeable than when I tried it on 10/27.

Update 4/7/2016
I moved this beer from a 6 gallon carboy to a 5 gallon carboy today. I racked the beer onto 1 pound of Simplicity Belgian Candi Syrup and two partially charred medium+ French oak cubes. I wasn't originally planning on using the candi syrup, but I wasn't satisfied with the tartness I was getting out of the Petite Prince dregs. I'm hoping a little food will help drop the pH a bit more. The beer definitely smells acidic, but the flavor is too mellow for my liking.

Update 6/25/2016
I bottled this beer last night. For the hibiscus, I put the 3oz of hibiscus in a French press, then added about three cups of hot water. This went into the fridge and was left to "brew" for about 24 hours. Midway through, I gently stirred it. The tea was then added to the bottling bucket along with the priming sugar and the beer was racked on top. Appearance-wise, this beer is a nice pinkish red and has really good clarity at room temp. That may change once it's conditioned and chilled. It is tart, but it's not as intense as many of my sours. It's along the lines of lemonade and the hibiscus have added a nice berry character. I didn't take a pH reading at bottling, but I suspect it's in the 3.5-3.6 range. I'm definitely looking forward to trying this when it's fully conditioned, but it was good enough that I finished the last 8 ounces that was leftover in the bottling bucket.