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Reducing Oxygen in Your Finished Beer

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This week I look at methods to reduce oxygen in your finished beer. Oxygen is known to negatively impact beer flavor and long term stability. While oxygen is widely used at the beginning of fermentation to aid in yeast growth, the yeast effectively scrubs virtually all of the oxygen out of the beer during fermentation. […]
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Brewing Hoppier Sours for Aging: Barrels of Rings

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This is the first in a series of posts each covering an aspect of brewing mixed-fermentation barrel-aged beers where my opinions have changed significantly since I wrote American Sour Beers. Each post will focus on our process, recipe, and results for one of the beers in the Sapwood Cellars Shipping Club. This one covers Barrels of Rings, aka our 40 IBU hazy pale ale (Rings of Light) fermented in barrels with house microbes, then dry hopped with Citra Cryo.



The longer I brew mixed-fermentation beers, the more I appreciate just how important the hopping rate is. Controlling lactic acid production by inhibiting lactobacillus is hops' most well-appreciated function in sour beers. Hop compounds become more effective at inhibiting Lactobacillus as the pH drops, creating a natural "limit" on their lactic acid production. What it took me a long time to appreciate was how much hop compounds (beyond IBUs) lead to a greater expression of what I think of as classic Brett "funk."

When Scott and I began the mixed-fermentation program in 2018-2019, generally our issue was beers not souring enough. I started pulling levers (lower hopping rates, higher mash temps, less attenuative primary strains etc.) By 2020-2021, we were having excessive acid production... Most non-fruited beers were dropping to a firmly-acidic 3.1-3.3 pH, while fruited beers were often difficult to drink in quantity at 3.0-3.1 pH with some dipping to "obnoxiously acidic" high-2s. 

Fruit contributes simple sugars, which Lactobacillus love, and at the same time dilute the hop compounds in the beer. This can cause a precipitous pH drop. With so much beer already in barrels, my first maneuver was to begin dosing alpha acids into the beer along with fruit when there was already enough acid. We started with reduced iso-alpha-acids (e.g. tetralone/hexalone), but have moved onto Hopsteiner Alpha Extract 20% since it doesn't add perceived bitterness. About .1-.2 g per gallon stops acid production for our bacteria. These products don't significantly change the flavor or add additional aromatic complexity. As a side benefit, they enhance head retention. A small dry hop at this stage would be another option if you wanted stop acidification and add hop aromatics.

 


At this point we started upping the aged hop rate, or aiming for higher IBU targets when using fresh hops (~15-20 IBUs). At the same time (~2021) Scott and Ken (our head brewer) wanted to try barrel-aging more aromatically hoppy beers... I was resistant. I love hoppy-sour beers, I did a whole talk about them at the 2016 National Homebrewers Conference. Generally my approach had been to make sure the hops go into the beer as close to serving as possible (e.g., dry hop a barrel-aged sour after aging, brew a quick-turn hoppy Brett saison, add a whirlpool addition after kettle souring). I'd tasted too many barrel-soured IPAs and pale ales from great breweries that smelled like "old hoppy beer." That said, Ken and Scott convinced me! At our scale it is a relatively low risk to divert a few barrels of pale ale to see what happens.



We're already "aggressive" with our measures against oxygen pick-up (purging barrels with carbon dioxide before filling, purging the barrel-tool between each fill, purging the bottles before filling etc.), but when we fill barrels with pale ale wort we pull out all the tricks. Most importantly, we selected barrels that could be refilled without rinsing, leaving several gallons of "house culture" at the bottom of each. Our goal was to start the secondary fermentation as quickly as possible to protect the delicate hop compounds. I was amazed how good the resulting beer tasted!

What has really intrigued me is that the hoppier bases have almost universally produced finished beers I'd describe as more Brett-forward (earthy, funky, fruity, horse blanket). What I don't know is why! In American Sour Beers I cited research that Brett can free glycosides in hops, so that could explain the fruity. Maybe hops are just inhibiting Lactobacillus, giving the Brett a healthier environment (in lambics Brett tends to thrive before Pediococcus dramatically lowers the pH). Maybe I'm just being fooled and higher hopping rates (aged or fresh) are adding key compounds that I associate with the "funk" in a Cantillon, Orval (and many of my favorite American mixed-ferms)! These days our typical hopping rate is .5 lbs/bbl of aged hops at the start of the boil, and .5 lbs/bbl or fresh low alpha-acid hops in the whirlpool. 



Barrels of Rings is one of the bottles included with the first shipment of the Sapwood Cellars Shipping Club. It started as Rings of Light, brewed summer 2022, racked into barrels after primary fermentation, but before dry hopping. After 10 months of aging, we transfer directly from the two wine barrels into our blending tank (purged with 5.5 pounds of our selected Citra Cryo already in there). We agitated/roused and allowed to settle for a couple days, dropping the hops. Then we primed with sugar and rehydrated wine yeast (as we do for most of our barrel-aged sours) and partially carbonated the beer. As with the barrel fill, we're relying on CO2 purging of the bottles and the rapid refermentation to scavenge oxygen and preserve hop aromatics. 



Recipe: Barrels of Rings

OG: 1.063

65% Briess Brewer's 2-row

14% Great Western Malted White Wheat

13% Grain Millers Flaked Oats

8% Best Chit Malt

IBUs: 40

.5 lbs/bbl Meridian @ Whirlpool (212F)

1 lb/bbl New York Cascade @ Whirlpool (180F)

Bravo Salvo Hop Extract @ Whirlpool (180F)

Fermentation with Omega Cosmic Punch (the barrel sheet below is incorrect)

FG (Primary) 1.022

Brewed 8/5/22. Barrels filled 8/11/22 

Barrel #6: Fifth-fill Chambourcin red wine barrel that previously held our original barrel-aged pale ale, Measure Twice. That barrel was started with dregs from our collab with Free Will (Erma Extra), but along the way it was filled with bases that had dregs in primary from various American saisons (Casey and Holy Mountain).

Barrel #125: Second-fill Chardonnay white wine barrel that previously held a cider fermented with the Bootleg Biology Biology Mad Fermentationist Saison (plus we added the dregs from a stellar bottle of Barrique Wet Hop Reserve after filling).

6/21/23 116 gallons of beer from the two barrels transferred onto 5.5 pounds of 2022 Citra Cryo. 1.5 oz/gallon.

Carbonated to 2.05 vol, reyeasted with Premier Cuvee (rehydrated on a stir-plate with StartUp Nutrient), primed with enough glucose to add 1.1 vol of CO2 (~3.1 vol total in bottle). 

Final pH: 3.65

Final Gravity 1.009

7.1% ABV. 



Tasting Notes: Barrels of Rings

(My personal notes from a few months ago)

Smell - Nice blend of citrus (orange) and earthy-Bretty-funk. Still really fresh, no oxidative or old-hop aromatics. Really varied nose with a little pine sap, hay, and melon. Another hoppy base that got funkier than most of our bases. 

Appearance - Big dense white head, good retention. Light haze, very pale yellow.  Attractive. 

Taste - Light lemony tartness, but not sour-sour. Very saison-y. Some bitterness, but it doesn’t clash with the light bitterness. 

Mouthfeel - A touch of astringency. Great sptrizy carbonation. Medium-light body. 

Drinkability - Really nice. The bitterness does give it a different impression than a classic low-bitterness sour base. More saison-like. 

Changes for Next Time - Really good, not much to change on this one. Gin barrels would be fun. 



When visiting Epochal Barrel Fermented Ales in Scotland last year I was blown-away by how by how good (owner/brewer) Gareth Young's wild ales were aged on whole hops in the barrels for the entire secondary fermentation. I really enjoyed the first beer we did with it, Violet You're Turning Violet (Mosaic in the barrel, finished with a blend of wild and cultivated blueberries). It seems like a good option especially if you want variety in the hop intensity of a base, e.g., start with a more moderate hopped base and add hops to some barrels for blending options. 


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