A Look at Studies and Outreach to Breweries

Lupulin Powder in the Hop Stand

Intense juicy and resinous hop flavor and aroma, less astringent vegetal flavors while using half the amount of hop material–I’m interested! In this article, I look at some of the research surrounding hops, proteins, and clarity and how those might apply to using a new product called lupulin powder. I brew an experimental side-by-side Mosaic pellet to Mosaic lupulin powder beer and reach out to two breweries who have been included in the testing stages of LupuLN2 to get their opinions and results.

YCH Hops was nice enough to send me samples of their Mosaic lupulin powder product called LupuLN2, which they describe as being a purified lupulin powder containing most of the resin compounds and aromatic oils derived directly from whole hop flowers. They create LupuLN2 with a proprietary cryogenic separation process that preserves the aromatic hop components and removes most of the vegetal leafy material.

I reached out to YCH Hops to try and gather some more information on LupuLN2, specifically how they produce the powder and for confirmation that a large portion of the polyphenols are removed during processing, which is something I cover in more detail below. Here is some of what I received from YCH Hops:

“Whole hop cones are separated into concentrated lupulin and bract at extremely low temperatures, preserving each component of the hop; nothing is crushed. LupuLN2 offers brewers approximately twice the concentration of resin content of traditional T90 hop pellets and should be dosed at approximately half the amount by weight. Brewers should note that LupuLN2 will create intense hop flavor and aroma with reduced vegetal and polyphenol flavor contribution because the leafy, plant material has been removed. The flavor profile of LupuLN2 is variety specific, but more pronounced due to the concentration. LupuLN2 is available in hop powder and hop pellet form. It can be applied anywhere in the brewery but early kettle recommendations are not recommended for risk of boiling out the intense aroma.”

Lupulin Powder Hypothesis

We can theorize a few possible results from using lupulin powder compared to hops. The first is that lupulin powder may prevent fewer iso-alpha-acids from being stripped from solution simply from introducing less leafy material to the beer, which we know can pull some iso-alpha-acids acids out of solution. In addition, the bitterness added to the beer from dry hopping via humulinones should also be less because when the lupulin powder should contain less. This is because when pellets are made, the lupulin is broken exposing the alpha acids to something on the leaf material that is causing the oxidation from alpha acids to humulinones. So when using lupulin powder in the dry hop, you should retain more of your original hot-side bitterness in iso-alpha-acids and there should be less bittering potential from humulinones.1

The second possible outcome when using lupulin powder is that it might result in less total polyphenol extraction into the beer due to less total vegetal hop matter. During dry hopping, about 50-60% of total polyphenols can find their way into beer, which alters the final beer characteristics. 2 In one study, as the polyphenol content in beer increases via dry hopping so too did an increase in sensory bitterness, harsh, medicinal, and metallic tastes as well as the duration of such characteristics remaining on the palate. Although, some suggest this has more to do with humulinones than polyphenols as one paper estimated that humulinones have up to 7-10 times greater influence than polyphenols on dry hop sensory bitterness.3 This is all to say that dry hopping with lupulin powder may result in less of the cold-side bitterness or astringency that can result from large pellet dry hopping from humulinones and polyphenols.

Brewery Experiences with LupuLN2

In an effort to see how my experiences with LupuLN2 compared to others experimenting with the powder, I reached out and spoke to Joe Mohrfeld, the Director of Brewing at Pinthouse Pizza Brewpub in Austin TX, and formerly of Odell Brewing. Joe came on my radar after stumbling across a presentation online he recently gave before a YCH Hop & Brew Shool session on brewing with LupuLN2.

I also had the pleasure of speaking to Josh Hare, founder and Brewer at Hops and Grain Brewing also located in Austin TX, who has also experimented with LupuLN2. I was impressed with both Joe and Josh’s commitment to experimentation despite having the obvious economic pressures of selling beer and their willingness to share their results with me. Also worth noting is Hops and Grains efforts to understand the numbers behind the experiments, utilizing a growing list of lab equipment that will allow them to combine both their sensory data with some hard numbers.

Hops and Grain have settled in using about 40% of the total dry hop charge in lupulin powder for both Citra and Mosaic and slightly more when using Simcoe to get their desired aroma intensity. Pinthouse Pizza has experimented with Simcoe, Mosaic, and Citra so far and said when using about half the dry hop amount in lupulin powder compared to pellets, they have yielded as much as a barrel of additional beer in a 15 bbl batch due to less leafy material absorbing the beer, that’s like 250 pints! The additional beer should help offset the higher cost for the lupulin powder. I noticed the increased yield just brewing a 5-gallon batch, after filling my serving keg, the carboy used for dry hopping the powder still had about 3/4 gallon of beer, which I typically overshoot on purpose to yield 5 total gallons when using pellets due to absorption loss.

As was with my experience, it was Joe’s opinion that dry hopping with lupulin powder has a significant difference in the end product. Specifically, the powder seems to give a more intense and true varietal specific aroma, reminiscent of actually “being in the bail room.” Josh, who frequently visits hop suppliers and has also spent time in bailing drying rooms shared this sentiment saying the powder is the “most honest and true representation of the hop at their peak freshness.”

When dry hopping with 100% powder in beers previously designed around 100% pellet dry hop schedules, Pinthouse Pizza wasn’t thrilled with the results. In these beers, the hop aroma intensity was there, but it lacked the depth they were looking for. The sweet spot for them seems to be dry hopping with 30-50% with powder and the rest in pellets. This ratio seems to bridge the gap of softer fruit aromatics from the pellets with the brighter, more rounded, and intense aroma from the LupuLN2 while lowering the astringent harshness you can get with heavy pellet additions. Results are more encouraging in beers they have designed from the beginning with 100% powder dry hop schedules, however.

Josh at Hops and Grain in Austin TX has done side-by-side experiments brewing with lupulin powder against pellet beers (from the same hop-lot) and had his own trained sensory panel as well as consumers rate and give feedback on the beers. It was “nearly unanimous” that people chose the powder beer as the one they like the most.

Usage

Because I was using a Big Mouth Bubbler for the primary fermenter for this beer, I could see inside after I added the Mosaic LupuLN2 powder. Unlike pellets, which sat at the top for a short period but gradually fall into suspension, the powder just stuck around at the top for longer than I was comfortable with. I ended up coming back a few hours later and giving the fermenter a little nudge to encourage the powder to get into suspension. The first time Pinthoue Pizza dry hopped with LupULN2 powder they came back two days later psyched to pull a sample and found the beer didn’t have any aroma. After looking inside the tank, they could see the powder was still chilling on top of the beer just like they left it, suggesting this tendency to sit on top of the beer is probably more likely as the amount of powder is increased.

Picture is two days after PintHouse Pizza added lupulin powder to a tank (didn’t go into suspension).

In order to get lupulin powder into ssuspension, a brewery might need to use a recirculation tank or experiment with adding the powder directly to the fermenter prior to adding the wort, which would allow it to mix evenly as the beer is added and fermentation should push the powder around. This early addition could also potentially result in some biotransformations of hop compounds, however, I would worry about C02 pushing some of these aromatics out during the most active phases of fermentation. Homebrewers can easily nudge the powder into solution with a short swirl of the fermenter or even gently using a sanitized spoon to push the powder down into the beer.

The plus side, however, is once you do get the powder into the beer, it doesn’t seem to want to drop out. Unlike pellets, which will slowly sink to the bottom of the fermenter, the lupulin powder seems to want to stay suspended. This could explain the faster extraction times that some are reporting when using lupulin powder. If the hop powder is staying in suspended, this removes the need to agitate or circulate the beer to encourage both extraction and extraction time. Pinthouse Pizza found that just after 30 minutes of circulation, they seemed to have close to complete extraction! Hops and Grain also mentioned that when using lupulin powder the contact time needed for extraction was much less. Sounds to me like less tank time is another added bonus for pro brewers.

One potential downside of using large amounts of lupulin came from Hops and Grain that noticed when brewing a beer with 100% dry hopped lupulin powder without running the beer through their centrifuge, resulted in a beer with a gritty-like mouthfeel. I didn’t experience this in my beer, I did use a 300-micron filter around the dip tube in the keg which could have helped with this or I just didn’t use as much powder.

Brewing Experiment

To test out the advertised benefits of LupuLN2, I decided to brew a 10-gallon split batch NEIPA. Both 5-gallon batches would be exactly the same, the only difference was one would get whirlpool and dry hops with LupuLN2 and the other would get twice the amount in weight of Mosaic pellets to the powder in the whirlpool and dry hop. This was the plan anyways. I frequently make easily avoidable mistakes and I came through in the clutch in this experiment. A couple days after dry hopping the beers, I was sitting at a red light thinking about hops, as were the people waiting at the light with me, when it occurred to me that I dry hopped the wrong beers! So, to make this a positive mistake, what I’m examining here is how the dry hopping differs between lupulin powder and pellets and potentially, how the hop flavor from the whirlpool with powder can carry through in the final beer dry hopped with pellets.

I was excited to see how WLP007 would perform in an NEIPA, having tried most of the other commonly used strains the style having already tried Vermont Ale, Wyeast 1318, and RVA Manchester Ale with plans to experiment with WLP030 Thames Ale in the near future. By most accounts, WLP007 is an extremely fast working and flocculant strain that should leave beers reasonably clear without fining, but dry hopping during fermentation will likely stand in the way of clarity in my experience.

Recipe

Water: 100% Reverse Osmosis treated at .20 grams/gallon gypsum and .60 grams/gallon chloride
OG: 1.056
FG: 1.015
Mash PH: 5.36

Grist:
60% Briess 2-Row
22% Briess Wheat – White Malt
18% Flaked Oats
Mash for 60 Minutes at 157°F

Hops:
12 grams Nugget at 60 minutes (both beers)
2 ounces Mosaic Lupulin Powder 25 Minute Hop Stand
or
4 ounces Mosaic Pellets 25 Minute Hop Stand

Dry Hops:
1 ounce Mosaic Lupulin Powder at Day 4 of Fermentation and 1 ounce Mosaic Lupulin Powder in serving keg
or
2 ounces Mosaic Pellet at Day 4 of Fermentation and 2 ounces Mosaic Pellets in serving keg

Lupulin Powder in the serving keg

Results

Although the Mosaic hops used for both the lupulin powder and pellets that I used were more than likely from different hop lots, which can have descriptor differences, I didn’t have a hard time at all telling the beers apart. The LupuLN2 beer screamed aroma compared to the pellet hopped beer. Specifically, the powder dry hopped beer produced big aromas of pine, sap, weed (legal), resin, peppercorn, with some tropical notes buried in there. I was reminded a lot of a beer I made with Experimental Pine Fruit hops, now called Eureka, which also had intense resinous characteristics with some cherry-like fruitiness. The Mosaic pellet dry hopped aroma was much less intense and had a softer edge to it. The pellets still produced a beer with some of that dank Mosaic quality but with some mixed sweet fruit aromas.

The flavor again showed how different the powder behaves then the pellets. Despite the pellet hopped beer having been whirlpooled with the LupULN2 powder (because of my mistake), the powder dry hopped beer had much clearer hop saturated flavor. The Mosaic pellet dry hop was much more astringent and vegetal on the palate, which seemed to hide the hop flavor (if it was present, to begin with). This could be explained by research indicating that the increase in bitterness and astringency found in the dry hopped beers correlates to the total polyphenol content. 4 Josh at Hops and Grain also suggested that the increased polyphenols when using pellets seems to “mute” the desired hop flavor.

I don’t want to make too big a deal out of this astringent/pellet aspect because I’ve been dry hopping and enjoying beers forever with them. But honestly, this “vegetal bitterness,” likely from both polyphenols and humulinones, is now something I’m detecting (unfortunately?) more and more of after using the powder. It’s almost like the astringency stops the flavor from coming through to match the nose. I much preferred the flavor aspect of the lupulin powder beer, or likely a mix of the two.

For homebrewers, I wonder if one way to maximize both the fruity aroma of the pellets and intensity in both flavor and aroma of the powder would be to dry hop early in the process with pellets and do small keg hop additions with the powder. The powder would mix fairly evenly when filling a keg and with quick extraction. The small amount of powder needed at this stage could aid in flavor without introducing large sums of vegetal material to the beer for long storage periods (until the keg kicks).

As far as using WLP007 in a NEIPA, I’m pleasantly surprised with the results. Compared to the other strains I’ve used, this one seems to stay out of the way the most. In other words, there doesn’t seem to be any big esters or yeast derived characteristics that stand out. It didn’t finish out too dry, which is something I prefer in the style. The mouthfeel was nice and full and soft. Really seems like a solid yeast choice for these flavorful beers, I’m curious to taste a WLP007 beer next to one of the other strains now.

Clarity

One unexpected result in my experience was the noticeable difference in clarity between the two beers. The pellet hopped beer, which had twice the amount of hop material in weight, was significantly cloudier and had more of that murky NEIPA look where the powder beer had more of a “hop sheen” (stole that phrase from Joe at Pinthouse Pizza). These results have gotten me to dig a little deeper into the literature of haze.

Mosaic Lupulin Powder | Mosaic Pellets

It seems to me that one possible reason for the haze is due to polyphenol extraction during dry hopping leading to colloidal haze, specifically formed by polyphenol and protein interaction. When polymerized (oxidized) polyphenols react with proteins, the bindings between protein and polyphenols are irreversible, resulting in a permanent haze.5

One study that sheds some light on to what’s going on with the haze by using a polyphenolic extract from spent hops and dosed beers and tested among other things, the turbidity levels. Upon the addition of polyphenols to the base beer, the authors found a haze would form. Over time, about 25% of the polyphenolic material would fall out of solution when the additions were on the high end (up to 200 mg/L), but that seems to indicate to me the majority are still hanging around in the beer. Sensory analysis of the higher polyphenol beers had higher marks for harsh, medicinal, and metallic tastes.6

A common practice when brewing NEIPAs is to dry hop early into fermentation, sometimes as early as brew day, but typically around days 2-4. This may be important as it relates to proteins and polyphenols. A study that looked at how the protein content in beer changes during active fermentation examined two different strains (WLP001 and KVL011). They found that with both strains, the protein content decreased during fermentation. Likely either degraded proteolytically by yeast or precipitating out with the yeast slurry. Specifically, WLP001 had a decrease of 16% and KVL001 decreased 42%.7

This is then a speculative paragraph based on the literature, but I wonder if dry hopping early into fermentation is then exposing the extracted polyphenols from the hops to a higher amount of available proteins in the wort, essentially increasing this polyphenol and protein interaction leading to permanent haze. It’s also interesting to think that as the experiment above showed, different strains may be leaving more proteins in the finished beer than others, which can also boost perceived mouthfeel8 (this sounds like NEIPA strains to me).

Getting back to lupulin powder, which consists mainly of only the aromatic resins and oils and not the vegetal polyphenols, it makes sense then that the result could be a clearer beer due to less polyphenol and protein interaction.

I’ll be interested to see how these two beers age as I’ve seen fairly aggressive oxidation in some of the NEIPAs I’ve brewed. This polyphenolic haze in these beers could potentially be part of the reason for this accelerated oxidation. Polyphenols have been shown to aid in flavor stability, but diminish colloidal stability and even “increase oxidation in the beer.” 9 This could be because although some classes of polyphenols might protect a beer from oxidation, other classes can actually pro-oxidants and can enhance beer staling.10 So it makes sense that some of the pro-oxidative polyphenols hanging around in the beer indefinitely could be causing the increased oxidation I’ve noticed, especially at warmer temperatures. So if the lupulin powder is introducing less of polyphenols to being with, perhaps the beer will age more gracefully.

Summary Points

  • In my experience, LupuLN2 produced a slightly clearer beer with noticeably more aroma intensity, which was danker than the same pellet variety (at least for Mosaic).
  • A combination of both pellets and lupulin powder might get you the best results. A combination of both the intense true variety characteristics with a sweeter fruitier character from the pellets. However, it really depends on what characteristics you’re looking for in the beer.
  • The lack of polyphenols in LupuLN2 seems to really go a long way in creating more perceived hop flavor without the vegetal bite large pellet additions can give you. In my little experience tasting the two beers, the less astringent aftertaste really paves the way for more lingering hop flavor vs. lingering bitterness/astringency which seemed to halt hop flavor.
  • When using large amounts of LupuLN2, it might be necessary to get creative to make sure the powder is actually getting into suspension and not just sitting on top of the beer. Once suspended, the powder might not drop out as easily as pellets.
  • Less time is likely needed to get full extraction with LupuLN2 than with whole cone or pellets.
  • Although I don’t have direct experience with it, I have been told that it’s possible that if you use a plate filter, the lupulin powder can gum things up and cause problems.

Footnotes

  1. Humulinone Formation in Hops and Hop Pellets and Its Implications for Dry Hopped Beers. (2016). Technical Quarterly TQ. doi:10.1094/tq-53-1-0227-01
  2. Forster, A., & Gahr, A. (2013) On the fate of certain hop substances during dry hopping. Brewing Science, 66, 93-103.
  3. Parkin, E. J. (2014). The influence of polyphenols and humulinones on bitterness in dry-hopped beer (Unpublished master’s thesis).
  4. Kaltner, D., Forster, C., Flieher, M., & Pinto, T. (2013). The influence of dry hopping on three different beer styles. Brauwelt International, 355-359
  5. L. Mélotte, INBR, UcL, XIIIth J. DE CLERCK CHAIR, September 2008
  6. S. (2008). Bitterness-Modifying Properties of Hop Polyphenols Extracted from Spent Hop Material. Journal of the American Society of Brewing Chemists. doi:10.1094/asbcj-2008-0619-01
  7. Berner, T., Jacobsen, S., & Arneborg, N. (2013). The impact of different ale brewer’s yeast strains on the proteome of immature beer. BMC Microbiology, 13(1), 215. doi:10.1186/1471-2180-13-215
  8. Narziss, L. Abriss der Bierbrauerei. Ferdinand Enke Verlage, Stuttgart, 1972.
  9. Oberholster A, Titus BM (2016) Review: Impact of Dry Hopping on Beer Flavor Stability. Ann Food Process Preserv 1(1): 1004.
  10. Irwin, A.J., Barker, R.L. and Pipasts, P., Journal of American Society of Brewing Chemists, 1991, 49, 140.
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