Experiment: Dry Hop Timing and Yeast-determined Haze
See the differences in haze and clarity when dry hop timing varies with a haze-positive and haze-neutral yeast strain.
May 15, 2024
Yeast-driven Haze
Lab trials turned up an important factor in haze for Omega Yeast’s researchers: yeast-driven haze. See the stark differences in haze outcomes when dry hop timing varied with what Omega Yeast researchers coined as “haze-positive” strains and “haze-neutral” strains. Yeast makes haze in conjunction with elements of the dry hop, and some strains are better at it than others.
The Experiment
For each series in this experiment, researchers inoculated nine identical flasks of wort with the same yeast on the same day, and then dry hopped them at different times during fermentation (note: the control flask — pictured above — was not dry hopped. The central flasks were dry hopped on progressive days — day zero, one, two, three, four and seven. The last flask was double dry-hopped, and received half early in fermentation and half late).
Test Yourself
Can you identify which series in the image above was fermented with British V (haze-positive) and which with Chico, AKA West Coast Ale I (haze-neutral).
TIP: look for substantial haze with later dry hop timing to find the haze-positive strain. Keep scrolling for the solution (below)!
| Haze-positive | Haze-neutral |
|---|---|
| British Ale I | Bayern Lager |
| British Ale V | British Ale VIII |
| East Coast Ale | Daybreak V |
| Hefeweizen Ale I | DIPA (Conan) |
| Irish Ale | French Saison |
| Kolsch I | German Lager I |
| Kolsch II | Lutra Kveik |
| *Point Loma (W Coast Ale III) | Point Loma + |
| Scottish Ale | Tropical IPA |
| Voss Kveik | W Coast I (Chico) |
| West Coast Ale II |
DID YOU GET IT RIGHT?
Haze-positive
With British V, haze levels increased when the dry hop happened later during fermentation.
Haze-neutral
With West Coast Ale I haze levels are too low to establish a haze styling from a yeast-determined source, no matter when the dry hop happens.
Day of fermentation dry hop: control (none), “KO” (essentially at yeast pitch), day 4, day 7, and days 1&7 (double dry hopped).
BONUS
Flasks that received both an early- and a late-fermentation dry hop (“1&7”)consistently dropped clear. This was like how the early-fermentation dry hop alone behaved. That means the early-fermentation dry hop has a dominant clarifying effect; and that phenomenon could be useful for brewers who want clarity instead of haze.
It’s hard to tell in the pictures of the flask series up above — at the time those photograph were taken the flasks were still somewhat active with yeast in suspension. This photo from an additional experiment shows the phenomenon much more clearly.
SUMMARY
If you understand yeast-contributed haze in relation to dry hop timing, and how it differs with haze-positive and haze-neutral strains, hopefully it was pretty easy to spot which was which:
- Haze-positive strains can contribute significant levels of haze in beer in conjunction with mid-to-late fermentation dry hop timing (and can drop clear with early-fermentation dry hop timing), thanks to something going on with their version of the HZY1 gene.
- Haze-neutral strains don’t ever achieve significant levels of yeast-driven haze.
- And, an early- and late-fermentation double dry hop behaves like early-fermentation dry hop in terms of haze. The early-fermentation dry hop dominates even with later-fermentation dry hopping.
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