Souring a Beer with Acid Malt - Ithaca Brute Style

It is hard not to get embedded in a rut when you really get into brewing sour beers. The investments of time and effort are so big that it discourages major risk taking (just take a look at all of the lambic brewers who essentially brew only one beer!). While I'm confident enough to adjust the grain bill, or add interesting new ingredients, my basic method hasn't changed much since I stared to be happy with the results a few years ago. As I hinted at in my Great Souring Experiment post, I’d like to try mimicking the methods that several respected craft breweries are using. I doubt all of these batches will be as good as my default, but maybe I will find a way to make sour beers that is faster, more reliable, or produces a unique flavor.

My first attempt at a new method was to use the one that head brewer Jeff O'Neil developed while at Ithaca Beer Company to produce the pale sour Brute. He has since moved on to Peekskill Brewing, which sounds like it will allow more freedom for him to experiment. The basic idea of the method is to use a significant proportion of acid malt in the mash, a hot saccharification rest, and a clean primary fermentation with only Brett pitched into secondary. The combination of mashing at both a low pH and high temperature creates a largely unfermentable (to brewer's yeast) wort. Brute starts with a hot primary fermentation with their house English ale yeast and then crash cools when it reaches about 50% apparent attenuation. Oak spirals and Brett Drie are then added and allowed to age for close to a year.

I started the mash for my inspired by batch at 159 F and allowed it to convert before adding the acid malt. Ithaca does not wait to add the acid malt, but I was a bit worried about getting really terrible starch to sugar conversion. I initially added 1.5 lbs of the tangy sourdough-flavored acid malt from Weyermann. When this didn’t result in a pH as low as I expected I added another 1.5 lbs. Now at 20% acid malt, the mash made it down to a pH of 4.5. As pH is a logarithmic scale, the final pH of Brute ~3.7 would require more than six times as much acid to reach. On their website Weyermann suggests 8% acid malt to sour a quick Berliner weisse, but I don't see how this would work when 20% in this beer gave no noticeable acidity.

I'm interested to see how far the Brett will be able to lower the pH on its own, it is also possible that Brute had other microbes, which had not been pitched, at work in the dedicated tank. Jeff has also said that he felt that seasonal temperature swings were a big part of what made Brute work, so I'll be letting this batch sit outside of my temperature controlled basement "fermentation" room next summer... maybe.

I failed to take many pictures during the brew day, but the American University journalism project were around throughout the day snapping photos of ever step of the process.

Acid Malt Soured Saison

Recipe Specifics
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Batch Size (Gal): 5.50
Total Grain (Lbs): 15.00
Anticipated OG: 1.069
Anticipated SRM: 4.1
Anticipated IBU: 10.1
Brewhouse Efficiency: 67 %
Wort Boil Time: 90 Minutes

Grain
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66.7% - 10.00 lbs. German Pilsener
20.0% - 3.00 lbs. Weyermann Sauer(acid) Malt
13.3% - 2.00 lbs. Wheat Malt

Hops
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0.50 oz. Hallertauer Tradition (Pellet, 6.00% AA) @ 60 min.

Yeast
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WYeast 3726 Farmhouse Ale

Water Profile
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Profile: Washington DC

Mash Schedule
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Sacch Rest 45 min @ 159 F
Acid Malt Sacch 30 min @ 159 F

Notes
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Brewed 12/04/11 with my neighbor Josh and the American University journalism crew

Mashed 45 minutes before adding the 1.5 lbs of Weyermann acid malt, waited 15 minutes, and pH was still at 5.5, added 1.5 lbs more which took it down to 4.5. Not quite as sour as I wanted, but it should be interesting.

Double batch sparge. Ended up with a bit more gravity than I wanted. Pitched yeast cake from one carboy of the first refill of the apple brandy solera. Shook to aerate.

Fermentation was going strong after 12 hours at 64 ambient. After 24 hours total I added 1 gallon of distilled water to lower the gravity.

After 48 hours placed it in a pot on the radiator to get it up to ~82 F.

12/10/11 Racked to secondary, down to 1.015. Not much acidity, I may have to pitch more microbes that I was intending.

1/13/12 Added ECY Brett Blend #1 via dregs from my Brett'd Rye Saison.

10/29/12 Bottled 2.25 gallons with 2.5 oz of table sugar. Finished at 1.007 (8.2% ABV), lower FG than Brute. Racked the rest onto ~4 lbs of frozen/thawed white nectarines.

1/24/13 Bottled the 2.5 gallons on fruit with 2 1/8 oz of table sugar. Great fresh nectarine aromatics.

6/10/13 Tasting notes for both the plain and nectarine versions. Very pleased with both, solid acidity, appealing flavors, very drinkable despite the strength.