Citra-Galaxy NEIPA: Bioconversion

There has been passionate discussion about hop bioconversion, especially in relation to NEIPA. Studies have shown geraniol in hops like Citra is converted during fermentation into citronellol when there is excess linalool present. But what does this mean for your beer? I talked to Stan Hieronymus when planning an experiment based on his suggestion to use other linalool and geraniol rich hops to mimic Citra. He directed me to a more recent study from the same team that suggested the thiol 4-MSP (aka 4-MMP) has a synergistic effect with these terpenes. Some hops (e.g., Citra, Centennial) contain linalool, geraniol, and 4-MSP and thus can be used as a single hop to create a fantastic IPA.

The question I set out to answer was whether the same flavors can be achieved piecemeal by adding individual hops to fill in the background flavors and then dry hop with fancy hops to lend varietal character. It is a practical consideration because hops like Citra and Galaxy are in short supply, and often cost four times the price of less-sexy varieties. If we can only get our hands on a couple boxes of Citra for Sapwood Cellars' first year, how do we maximize the amount of Citra-forward IPA brewed?

The problem with blindly relying on the science regarding individual compounds is that you can miss the IPA through the hops. I selected Chinook (geraniol), Nugget (linalool), and Eureka (4-MSP). However, each contributes a variety of other aromatics, how would these come through?

Most of the bioconversion happens to terpenes extracted on the hot side, so how important is a mid-fermentation dose of dry hops? At the end of the combined boil I added Chinook, Nugget, and Eureka for the whirlpool. On day two, I dry hopped one fermentor with more Chinook and Nugget and the other with Citra and Galaxy. I then keg-hopped both with Citra/Galaxy in stainless steel hop filters (rather than the nylon knee-highs I'd been using).

I hooked the two kegs up in the kegerator without paying attention to which beer was on which tap. I was able to identify them almost immediately with my first carbonated sample a week later. I thought that was enough to skip the triangle test and go straight to preference. I brought a growler of each to the DC Homebrewer’s August meeting. There were lots of strong opinions (I didn't tell the homebrewers what I was testing, but asked them to focus on the hop character). With 11 votes to 8, the beer with Citra and Galaxy as the first dry hop addition won, but not by as much as I would have guessed. Here are select comments that each elicited:

Cheaper Hops - Nugget/Chinook: West Coast, spicy, subtle, vegetal, fruitier, aromatic (several), "Galaxy/Mosaic," more bitter (several), minerally, crisper.

Cheater Hops - Citra/Galaxy: Piney, fruity, juicy, berry, fresh orange, hoppier, sweeter, restrained, rounder, more dry hop, more aromatic.

These results were of the beers after less than two weeks in the keg. While freshness is essential for NEIPA given their sensitivity to oxygen, a little extra time post-fermentation can be beneficial. I’ve gotten a few emails from brewers disappointed with the “juiciness” of their beer a few days after kegging. It often takes time for the yeast (which is coated in hop compounds) and lupulin to settle out and clear the way for those juicy flavors. In this case I also found the extraction of the keg hops took a couple weeks, with the Cheaper Hop half tasting more like Citra and Galaxy now a month after kegging.

I think this experiment contradicts the old adage that dry hopping only effects aroma. Flavor and aroma are inextricably linked. Dry hopping can even decrease IBUs, or it can add bitterness depending on how much iso-alpha is in the beer already. There are few simple rules in brewing!

For my tastes too much maltiness distracts from the hops in NEIPAs. I don’t care for the full Maris Otter crackery flavor that some examples have. For this batch I started with a similar malt bill to my previous NEIPA, but subbed in Golden Promise for about 2/3 of the base malt. Golden Promise is softer than some of the other British base malts, and I thought it worked well here to increase the perception of maltiness without distracting.

Cheaper Hops

Smell – Nice mix of bright citrus juice (orange) and more classic Pacific-Northwest hop-bag resin. Has some of that bold Citra/Galaxy tropical, but it is a component rather than a feature. Toasty notes, nice depth addition from the Golden Promise.

Appearance – Maximum haze without muddiness. Slightly darker than some of my previous batches, which likely increases the appearance of haze. Nice head, but retention isn't remarkable.

Taste – Falls a little short of full-on NEIPA, lacking that wonderful saturated juicy hop flavor. Although the fullness of the hop character has increased while sitting on the keg hops. Pineapple, orange candy, and dank. Slightly sharp bitterness, a bit lupulin bite in the throat.

Mouthfeel – Smooth, but a little chalky in the finish.

Drinkability & Notes – A nice solid NEIPA with some character that might appeal to the cross-over West Coast drinker. Certainly nice to be able to get that good an IPA from 2/3 inexpensive hops, but it isn’t fooling anyone.

Cheater Hops

Smell – Similar notes of pineapple and orange, but without an undercurrent of resin. Not an especially amped nose compared recent batches with London III, lacking the oomph of my favorite NEIPAs. Perhaps the malt getting in the way?

Appearance – Identical.

Taste – It has that saturated fancy hop (4-MSP) flavor. Bright, fruity, really juicy. Nice toasty-malty note in the finish, lingering with just a touch of resin. Firm bitterness. The aftertaste is where I really get the Citra-Galaxy rounded tropical fruit compared to the Cheaper hops.

Mouthfeel – Seems slightly crisper, less chalky.

Drinkability & Notes – I’m a sucker for that full fruity flavor with a slight weirdness from the hops. Drinkable and wonderfully hoppy. The hot-side additions of less expensive hops really worked in this batch!

Changes for Next Time – Clearly that early dry hop addition isn’t all about bio-conversion. I’ll be focusing my linalool and geraniol additions at the end of the boil and 4-SMP hops at that early dry hop.

Recipe

Batch Size: 5.50 gal
SRM: 3.8
IBU: 78.1
OG: 1.060
FG: 1.016
ABV: 5.8%
Final pH: 4.52
Brewhouse Efficiency: 68%
Boil Time: 60 mins

Fermentables
-----------------
37.6% - 5 lbs Simpsons Golden Promise
22.5% - 3 lbs Rahr 2-row Brewer's Malt
21.1% - 2.8 lbs Quaker Quick Oats
18.8% - 2.5 lbs Weyermann Carafoam

Mash
-------
Mash In - 60 min @ 154F

Hops
-------
1.00 oz Nugget (Pellets, 13.00% AA) @ 15 min
2.00 oz Chinook (Pellets, 13.00% AA) @ Whirlpool 30 min
2.00 oz Nugget (Pellets, 13.00% AA) @ Whirlpool 30 min
1.00 oz Eureka (Pellets, 18.00% AA) @ Whirlpool 30 min

Cheaper Hops Option:
3.00 oz Chinook (Pellets, 13.00% AA) @ Dry Hop Day 2
3.00 oz Nugget (Pellets, 13.00% AA) @ Dry Hop Day 2

Cheater Hops Option:
3.00 oz Galaxy (Pellets, 14.00% AA) @ Dry Hop Day 2
3.00 oz Citra (Pellets, 12.00% AA) @ Dry Hop Day 2

Both
1.50 oz Citra (Pellets, 12.00% AA) @ Keg Hop
1.50 oz Galaxy (Pellets, 14.00% AA) @ Keg Hop

Water
-------
5 g Calcium Chloride @ Mash
4 g Gypsum (Calcium Sulfate) @ Mash
.5 tsp Lactic Acid @ Mash

Calcium	Chloride	Sulfate	Sodium	Magnesium	Carbonate
90	90	90	10	5	45

Yeast
-------
SafAle S-04 English Ale

Notes
-------
Scaled to be brewed as either half of the batch.

Brewed 8/6/17 with Collin

Mash pH initially 5.55 pre-acid. Acid brought it down to 5.26. Around 5.4 if it had been cooled.

Whirlpool hops added right at flame-out.

Used ice to get it down to 70F. 5 gallons into each fermentor. Shook to aerate and pitched S-04 directly. Left at 64F to ferment.

Up to ~68F internal by 24 hours.

After two days down to 1.024 (60% AA) added 3 oz Nugget/Chinook to FV1, and 3 oz each Galaxy/Citra to FV2. Fermentation slowing down. Increased ambient temperature to 68F.

8/16/17 Kegged both. ~4 gallons of FV1, 4.5 of FV2. Quad-flushed. 1.5 oz each of Citra and Galaxy in the new screens, weighted with marbles.

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Backyard Gruit: Alehoof and Yarrow

Why brew a light, refreshing “lawnmower” ale to be enjoyed after yard work when you can brew a batch flavored with lawnmower clippings? Well not literally, but this is a batch of sour beer flavored with ingredients foraged from what would otherwise be clipped. A beer that captures the aroma of summertime in my backyard!

In April, when I posted a photo of my North-Eastern Australian IPA sitting on my lawn, Caleb Levar (I tried to send him bottle dregs to culture in 2011) pointed out that the ground cover with vibrant purples flowers was a brewing herb:

use the Creeping Charlie in that picture!

— Caleb Levar (@celevar1) April 3, 2017

I met Carlos, my brewing partner for the day, back in February when Blane invited us to brew (with juniper, smoke, and kveik). Carlos is an enthusiastic forager, and talked about a variety of exciting projects like malting his own quinoa for a 100% quinoa beer! We’d been looking for an excuse to brew together again since, so this was perfect!

I hadn’t heard of ground ivy beer previously, but in addition to being an invasive species, it is a historic English/saxon brewing herb (often called alehoof). Brewing herbs growing wild is a great argument for lawn as a meadow in addition to avoiding the use of fertilizer and herbicide! Crushed, alehoof smells a bit like parsley crossed with arugula, green but not grassy, a little peppery. That flavor is rich in terpenes, phenols, and vitamin C. The list of volatiles in this study for Glechoma hederacea is so long that it is difficult to pick out what compounds are responsible for it's flavor. However, it contains many of the terpenes in hops including important aroma molecules: humulene, caryophyllene, linalool, and traces of myrcene and geraniol.

When I visited my parents a couple months later, my father showed off the yarrow in his garden on Cape Cod (a few feet from where my mead is buried). Another classic brewing herb! I had read that yarrow loses its most interesting aromatics during drying, so this was a rare opportunity to try it fresh. β-pinene, linalool, and β-caryophyllene are found in yarrow and hops, so another chance of a beer with flavors reminiscent of a wet hopped ale? I actually have a keg on wine-barrel solera still sitting in my basement with fresh yarrow from Spruce on Tap that I purchased when I brewed my India Pale Gruit... I should probably pull a sample.

For the alehoof  usage-rate I referenced Sacred and Herbal Healing Beers (3 oz dried/12 quarts per roughly three gallons), and Growler Magazine (6–8 quarts per 5 gallons). Both sounded like a lot of an herb I'd never tasted in a beer, so I went easy with two quarts in 11 gallons at the start of the boil. We split the yarrow adding the leaves with the alehoof, and the flower heads and stems in the whirlpool treating it like aroma hops. Again though, 2 oz in 11 gallons is less than most recipes I could find.

Carlos brought a bag of pink salt from Maras, an Incan salt production facility still in use today. A stream of subterranean brine in diverted into shallow pools and allowed to evaporate. The light reddish color comes from traces of iron. Iron isn't a positive beer additive, but using ancient salt is romantic with traditional herbs. Salt is a classic part of gose, and can help meld bitterness and acidity (as in a salad).

We planned to split the batch, but Carlos had a flight to Peru a week after brewing to cover between head brewers at a small brewery. I revived Right Proper's House Lacto culture (which did good work in my lone qunioa beer) and pitched the other half with GigaYeast's Sour Cherry Funk. I didn't have a plan for that pack, so this seemed like a good test. It is still in the fermentor, this tasting is of the Right Proper half.

Backyard Gruit-Gose

Smell – Slight spicy and herbaceous aroma. There are some green notes that with the knowledge of what is in there reminds me of mowing. Luckily it doesn’t remind me of boiled greens. Not an overpowering or aggressive gruit/herbal character, allowing room for grainy maltiness to come through.

Appearance – Glowing yellow, cloudy. Dense white head. Better head retention than my previous efforts with this culture. Still not fantastic, but enough to snap a few pictures in the backyard. Good lacing.

Taste – Big lactic acidity, tangy. Minimal sweetness and bitterness. There are herbal notes, but also a citrusy (orange and lemon) character I usually associate with lightly dry-hopped sours.

Mouthfeel – Light and bright. This is the second sour in a row on tap that doesn’t seem to be getting as carbonated as the other taps despite the same pressure. Could be a little bubblier.

Drinkability & Notes – The sourness is at the high end of what I’m looking for. The pH reading was 3.03, but it doesn't taste quite that sour. Otherwise refreshing, just not the sort of beer I naturally gravitate to for a second pour.

Changes for Next Time – I’m satisfied with the experiment. The fresh herbs do lend a fresher flavor than dried herbs, less concentrated and distinct. Doubling the herbs would create a more “obvious” flavor, but as a beer on tap subtlety is a virtue. I’ll wait for the other half to see how it compares with age before making final proclamations on the process.

Recipe

Batch Size: 11.00 gal
SRM: 3.2
IBU: 0.0
OG: 1.047
FG: 1.009
ABV: 4.9%
Final pH: 3.03
Brewhouse Efficiency: 70%
Boil Time: 60 Mins

Fermentables
-----------------
90.0% - 18 lbs Rahr 2-Row Brewer's Malt
10.0% - 2 lbs Briess Red Wheat Malt


Mash
-------
Mash In - 60 min @ 153F

Hops
-------
None

Other
-------
3.50 oz Ground Ivy @ 60 mins
1.00 oz Yarrow Leaves @ 60 mins
0.50 oz Peruvian Salt (Mines of Maras) @ 15 min
1.00 oz Yarrow Flowers/Stems @ Whirlpool

Water
-------

Calcium	Chloride	Sulfate	Sodium	Magnesium	Carbonate
50	30	50	15	10	90

Yeast
-------
Right Proper House Lacto Blend

Notes
-------
Brewed 7/8/17 with Carlos

Made a 3.5L starter with the Right Proper House Lacto culture that had been sitting in my fridge for... six months. Seemed to start up well.

Ground ivy harvested from the backyard that morning. Yarrow harvested three days prior on Cape Cod.

Chilled to 80F and pitched RP Lacto (left at 80F). Other half left at 65F for 6 hours to drop a bit cooler before pitching Cherry Funk (left at 65F).

7/22/17 Racked the Giga half to secondary (1.012, mildly tart).

7/26/17 Kegged the Right Proper half with 3 oz of table sugar to carbonate (1.009, firm acidity). Seal was not good, didn't hold pressure.

8/6/17 Moved the Right Proper half to the keggerator, fixed the lid, and attached to gas. Final pH 3.03... not confident in that reading.

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