Author: Matt Del Fiacco

I’ve been watching IPA trends with great interest. While I don’t tend to brew IPA much myself, I’m incredibly interested in the methods brewers use to extract hop aroma and flavor without the accompanying bitterness. The pursuit of strong-but-soft hop quality characteristics of hazy NEIPA points to hop additions occurring later in the boil as being crucial to achieving this sought after character, as it reduced the isomerization of alpha acids while also allowing for less time to drive off other essential hop oils.

An increasingly popular method of imparting a beer with as much hoppy goodness as possible is the hop stand, a post-boil hop addition that occurs prior to chilling the wort to pitching temperatures. The general idea behind this method is that a wort temperature of around 170°F/77°C will allow for the extraction of desirable flavor and aroma oils from the hops without isomerizing the alpha acids, thereby reducing what they contribute to bitterness.

The thing about hop stands is that there are myriad approaches brewers can take, from adding a dose of hops immediately at flameout and letting them sit for a specific amount of time to chilling the wort to a certain temperature before adding the hops and letting them rest. With a prior xBmt comparing hop stands occurring at either flameout or 170°F/77°C returning non-significant results, I couldn’t help but wonder if an even lower temperature might make a difference. In theory, wort temperature at flameout is still hot enough to isomerize alpha acids, but surely there has to be a point where only hop oils are extracted without bitterness. Indeed, an experiment performed by the Experimental Brewing IGORs indicated tasters were capable of distinguishing a beer with a flameout hop stand from a similar beer where the hop stand occurred once the wort was chilled to 120°F/49°C, even when accounting for potentially flawed data. Would this be something I could replicate? I was curious to find out!



| PURPOSE |

To evaluate the differences between beers where the hop stand additions were made at either flameout or once the wort was chilled to 120˚F/49˚C.

| METHODS |

Since this batch doubled as a Hop Chronicle beer, I went with a simple American Blonde to let the hops stand out.

Look Me In The Eye Hoppy Blonde Ale

Recipe Details Batch Size Boil Time IBU SRM Est. OG Est. FG ABV 5.5 gal 60 min 25.4 IBUs 3.6 SRM 1.043 1.011 4.3 % Actuals 1.043 1.005 5.0 % Fermentables Name Amount % Pale Malt, 2-Row (Rahr) 8.375 lbs 94.37 Carahell (Weyermann) 8 oz 5.63 Hops Name Amount Time Use Form Alpha % Medusa 16 g 60 min Boil Pellet 3.8 Medusa 21 g 30 min Boil Pellet 3.8 Medusa 40 g 15 min Boil Pellet 3.8 Medusa 33 g 20 min Aroma Pellet 3.8 Yeast Name Lab Attenuation Temperature Flagship (A07) Imperial Yeast 75% 60°F - 72°F Notes Water Profile: Yellow Bitter in Bru’n Water Spreadsheet

A couple days before brewing, I spun up a starter of Imperial Organics A07 Flagship yeast that would later be split between the batches.

I was in the middle of moving during this brew day, so my parents graciously allowed me to set my stuff up in their backyard so I could knock this xBmt out.

I adjusted RO water with minerals then weighed out and milled the grains while it was warming up to strike temperature.

With the water heated, I dropped mashed in, briefly stirring gently before turning on the pumps for recirculation.

After letting the mash settle for a couple minutes, I confirmed I’d hit my intended mash temperature.

After the 60 minute mash, I removed the grain from the wort, allowing it to drip into the kettle as I began heating the wort.

At this point, I measured out equal amounts of hops for both batches.

Once a boil was reached, hop additions were made at the times stated in the recipe.

After 60 minutes, I cut the heat to both batches and immediately added the flameout hop addition to one batch and let it continue to recirculate without chilling. For the other batch, I quickly chilled the wort to 120°F/49°C, set my controller to maintain this temperature, then added the hop charge and turned the recirculation pump on.

I let both batches “stand” for precisely 20 minutes before chilling to my desired pitching temperature, after which they were racked to fermentation kegs.

Hydrometer measurements at this point confirmed both batches were sitting at the same OG.

I placed the fermentors next to each other in my temperature controlled chamber, attached blowoff tubes, and pitched the yeast.

After a week of vigorous fermentation activity, dry hops were added to each batch and they were left 3 more days before I took hydrometer measurements indicating FG had been reached.

I cold crashed, fined with gelatin, then pressure transferred the beers to serving kegs.

After a period of burst carbonation, I reduced the CO2 to serving pressure and let the beers condition for a few days before serving them to participants. Even after an additional week of cold conditioning, they never dropped clear, which I’ve seen before in hop stand beers.

| RESULTS |

A panel of 22 people with varying degrees of experience participated in this xBmt. Each taster, blind to the variable being investigated, was served 2 samples of the beer where the hop stand occurred at flameout and 1 sample of the beer with a 120°F/49°C hop stand in different colored opaque cups then instructed to select the unique sample. At this sample size, a total of 12 (p<0.05) correct selections would have been required to achieve statistical significance, though only 9 tasters (p=0.29) chose the different beer, indicating tasters were unable to reliably distinguish a beer made with a flameout temperature hop stand from one where the hops were added at 120°F/49°C.

My Impressions: I went into my own blind triangle tests with shaky confidence, and sure enough, even having sampled both beers numerous times, I just wasn’t able to tell them apart consistently. Over 4 attempts, I was only correct twice, and I admit those both felt like random guesses. Overall, the beers had a lot of hop character, which I perceived as being quite dank with hints of tropical fruit and apricot. The malt presence was pretty soft. I really enjoyed both beers, neither had a harsh bitterness, and both were full of delicious hop character!

| DISCUSSION |

Based on the conventional wisdom, adding a charge of hops immediately at flameout when the wort is still near boiling temperature ought to result in a beer with a higher level of bitterness compared to adding the hops to cooler wort. Moreover, performing such a hop stand in cooler wort should, or at least is believed by many to, restrict the volatilization of delicate hop oils, thereby resulting in a beer that’s not only less bitter, but more aromatic and flavorful. However, the fact participants in this xBmt were unable to reliably distinguish a beer where the hop stand was performed at flameout from one where hops weren’t added until the wort was 120˚F/49˚C calls this wisdom into question.

I can’t say for sure what’s going on here, and I certainly didn’t expect these results, but I have a few theories. First off, the fact the level of bitterness between the beers didn’t immediately give it away suggests that isomerized alpha acids from kettle hop additions may contribute a similar quality of bitterness as non-isomerized alpha acids from hops added as after the boil. After all, hops are bitter, as anyone who has been silly enough to eat a raw pellet knows, and that bitterness goes somewhere when added to even cool wort or beer. Ultimately, the beers in this xBmt received the same amount of the same hops, and while the calculated and maybe even actual IBUs were different based on wort temperature, it would seem that difference wasn’t large enough to impart a noticeable difference. The second and perhaps even more confounding thing about these results is the fact the cooler hop stand beer wasn’t noticeably more aromatic and flavorful than the flameout hop stand beer, suggesting volatilization occurred at a similar rate in both. Is it possible hop stands at cooler temperatures, at least on the homebrew scale, are no more beneficial than tossing hops in at flameout or maybe even during the boil?

Despite these results, my inclination is to continue dropping the temperature of the wort when performing hop stands in hopes that I ward off as much bitterness as possible. Even if it doesn’t make a difference, it’s an easy enough practice that continuing to do it doesn’t change much about my brew day, though if ever I’m pressed for time, I certainly won’t hesitate to toss my hops in at flameout.

If you have thoughts about this xBmt, please feel free to share in the comments section below!

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