Haze redux

Haze has more layers than initially thought. In short, malts, yeast and hops all have important roles to play in different sources of haze. And it matters where your haze is coming from if you want to be able to control it. In terms of reliability, consistency, and ease of process a haze-positive yeast strain will do a lot to lay a foundation for haze, and a haze-neutral strain is going to go a long way in paving the way for clarity. 

This is what we can do to optimize what exists — but that’s not all we can do. Omega Yeast researchers also found the particular gene that’s responsible for haze. Its discovery means they are also creating new solutions in new tools for brewers. This is what’s new in haze. 

Doors open with the HZY1 gene

Observations in experimentation about yeast-determined haze suggested to Omega Yeast’s researchers that there was a genetic cause, so they set out to look for it — and they found it. The gene had previously been without a known function. Omega Yeast’s R&D team named it HZY1.

Examining the gene’s structure for clues on how it engages with haze, there were massive expansions made up of repetitive sequences in haze-positive strains. Comparatively, haze-neutral strains’ version of the gene were smaller, and showed fewer repetitions. 

When the Omega Yeast team went back to the whole yeast strain catalog and categorized strains by how much haze they contribute with a later dry hop, some strains were more strongly haze-positive than others. 

We see the diversity that occurred there reflected in the genetics, too: there are different degrees, locations and sizes to the repeats. 

  1. The long and short of it
    There was a good correlation between the size of the expansion in the HZY1 gene and a strain’s ability to make haze in a haze-positive manner. That meant selecting a strain by its HZY1 signature was predictive of how it performed. This was a great sign they’d found the right gene. 
  2. Knock it off
    They next knocked out the hazy version of the gene in haze-positive strains, which successfully resulted in the loss of haze. That was another great sign that Omega Yeast’s brewing scientists found the right factor. 
  3. Opportunity knocks
    Being able to knock out the HZY1 gene also meant there was now a perfect isogenic system for testing how haze affects flavor. It was now possible to brew identical beers with only a haze difference. 

The future is now

Now that Omega Yeast researches have the genetic target for haze, there are a lot of opportunities. They can design strains to be more reliable based on how brewers want to use them. 

They are already trialing strains with brewers in which they’ve disabled yeast-determined haze. Hazy versions of previously non-hazy strains are also on the horizon after that. Are there any strains on your hazy or non-hazy wishlist? 

  • A juicy non-hazy? British V is known for being good at making haze and has juicy esters. If we disable its HZY1 gene, we could make a juicy strain that’s great for clear styles. 
  • A chico fino? The haze Chico makes is low, but it isn’t zero. When Omega Yeast deletes its HZY1 gene, we get a further reduction in haze. This could be a great option for reliably clear beer with minimal fuss. 

hzy1Δ in practice

Even haze-positive strains can become haze-reduced, giving brewers the opportunity to make their classic juicy IPAs without the haze. We ran one such trial with the team at Cincinnati’s Rhinegeist Brewery.

Rhinegeist ran a split fermentation with Voss Kveik (OYL- 061) and its haze-reduced counterpart (OYL-061 hzy1Δ) and presented their process and findings at the 2024 Ohio Craft Brewers Association conference. 

Their goals were threefold: 

  1. Set up a malt base that will contribute minimally to haze. 
  2. Late dry hop only to promote haze. 
  3. Ferment with OYL-061 vs. OYL-061 hzy1Δ.


Batch Size 7 bbl
Malt 100% 2‑row Origin Pilsner
Strain OYL-061 and OYL-061 hzy1Δ
Pitch Rate 1.0 million cells/°P/ml
Temperature 68°F
Fermentation end point 14 days
Whirlpool hops Amarillo (4lb), Citra (2lb), and Centennial (2lb)
Dry hop 5lb each Amarillo, Citra, Centennial
Cold crashed at Day 14 for one week and transferred to keg 

Trial stats

Sensory data from the Rhinegeist trial shows that the hazy and reduced-haze beers returned similar results.

Fermentation Trial Stats

StatSample A: OYL-061 hzy1ΔSample B: OYL-061
FG3.67°P (AE)3.06°P (AE)
Time of attenuation4 days4 days
pH at crash4.654.69
Color6.03 SRM6.21 SRM
Haze34 NTUs702 NTUs

In the end, panelists both at Rhinegeist and in the audience for the OCBA presentation rated the beers as having very similar sensory profiles — lightly fruity and moderately hoppy. Across all panelists, preference was a fairly even split.

What we can take away from this is that haze is not necessarily making a large contribution to the beer’s flavor profile, so brewers should see haze as a component of the overall tasting experience when determining how they’d like to present the beer and its flavors to their target audience.

Troubleshooting haze by strain selection

Often when brewers get in touch with Omega Yeast’s experts, Omega Yeast starts by asking the brewer what yeast they’re using, especially when it comes to haze. Whether you’re looking to clear up or make more haze, here are a few scenarios that are common topics for troubleshooting: 

Brewing clear beer while unknowingly using a haze-positive strain 

Some brewers have been using strains that they didn’t necessarily realize were haze-positive. One example of this is Point Loma (OYL-043): considered by some to be an offshoot or better version” of West Coast Ale I (OYL-004) aka Chico, but it also comes along with some haze-generating capabilities that makes it a useful tool for brewing hazy beers, and might work against the brewer in a clear beer, depending on certain factors. 

Difficulty generating haze while using a haze-neutral strain 

Extra Special (OYL-016) and West Coast Ale I are popular strain options for their reliability, and many brewers have tried and struggled to make hazy beers with them. As one brewer once told us, no matter what we do they always seem to drop clear.” We generally suggest reserving these strains for your non-hazy beers. While it isn’t impossible to achieve stable haze with these strains, it will be hard work to make it stick. 

Sometimes it’s hazy, sometimes it isn’t

Another case is the DIPA strain (OYL-052), commonly known as Conan. DIPA was one of those interesting scenarios in which brewers were finding that their beers sometimes dropped clear and other times remained hazy. This is a scenario in which dry hop timing can aid your process. Omega Yeast’s research has found that later dry hopping tends to produce stronger haze. 

Other questions we’ve received from brewers: 

  • What clarifying agents can we use and still make hazy beer? People often use Whirlfloc and it still makes a hazy beer, but Clarex and Biofine would reduce haze considerably. 
  • Does yeast contact help retain haze? As of right now, Omega Yeast’s research team is running experiments to see how the presence of yeast in the cone affects haze stability (if at all). Early results are leaning towards no”.
  • What’s next for haze? Next on the horizon, haze reduction. A reliable, haze-neutral strain like Chico can have its haze reduced, making it even easier to make West Coast IPAs super bright. Reducing haze on an already haze-neutral strain can help reduce the need for clarifying agents and may even allow some additional dry hopping without the concern for new haze formation. 

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