In March Garage Project and Hāpi Research held the second Hāpi Symposium, the first since 2019 after Covid postponements. It was a super-geeky day of talks from hop & yeast scientists, hop growers and brewers — a full-on download on the current hop science as well as glimpses of future trends.

Hāpi Research was established in 2018 by Garage Project and Freestyle Farms as a research & development programme for hops in New Zealand. Its mission is growing the hop farming and craft brewing industries in New Zealand, with a focus on sustainability & innovation. Funding comes from the government (MPI), hop growers like Freestyle Farms, research institutions and breweries including Garage Project. They have a hop breeding programme which is starting to produce new varieties which will hit the market in the next few years.

There were two main themes of the Hāpi Symposium: unlocking new flavour compounds in hops, and expanding the growing region for hops in New Zealand, with a related discussion about the terroir of hops — are there differences in the same varieties grown in different regions?


If you’re a lover of hoppy beers and pay attention to what’s written on labels you’ll probably have come across the word “thiols” increasingly over the last couple of years. If you’re not a student of beer labels but you like big juicy flavours in your hoppy beers, then you’ve certainly experienced the impact that thiols can have.

The talks at the symposium had me wracking my brain for the dim & distant memories of high school biochemistry lessons. I’ll try to summarise some of the key points without getting into the details of “valence bond cleaving” and other such delights!

Thiols are a group of highly aromatic compounds which give, amongst other things, the pungent gooseberry aromas in sauvignon blanc grapes. They can be found in varying levels in many New Zealand hops, most notably in Nelson Sauvin. Thiols exist in two forms: free and bound. The free thiols can be extracted simply by dissolving them in the beer, which is where we get some of the wonderful aromas from New Zealand hops. Bound thiols can be found in a lot of different hops, and even in malted barley. To get at the bound thiols you need to do some more serious biochemistry. Some yeasts will do some of this work (you may have heard the term “biotransformation” in relation to some hazy beers) and there are some enzymes which brewers can use.

Dr Laura Burns from Omega Yeast in Chicago talked about new strains of yeast created using CRISPR gene editing technology which will unlock those bound thiols, massively boosting the aroma and flavour content in beers. Unfortunately, this was a bit of a tease for New Zealand brewers as they won’t be able to get their hands on these yeasts due to New Zealand’s strict non-GM policies regarding importing of yeast. It seems likely that ways around these restrictions may be found over time, so look out for beers made with yeasts like Cosmic Punch in the future.

New hop regions

One of the other key topics was the expansion of hop growing regions beyond the “traditional” ones. In New Zealand the vast majority of hops are grown in the Nelson region but we had talks from people growing hops in the Nelson Lakes and even in Southland. In the USA they’re seeing an increase in hops being grown in areas such as Idaho, Colorado and even Florida. It will be a long time before these new regions get close to the amounts of hops grown in the more traditional regions such as Washington State and Oregon, but it’s interesting to see the shift.

These shifts are certainly being influenced by climate change. Wildfires in the Pacific Northwest of the USA have led to batches of hops being discarded due to smoke taint, and both drought and flooding have caused issues in the USA and New Zealand. Hops have a narrow window of sunlight hours and temperature that they like to grow in, so as the climate shifts some areas may become unviable for growing good quality hops, while other areas may open up.

Common themes

Throughout the various talks and panel sessions, a couple of common themes emerged.

The first was the importance of sensory analysis — regularly smelling and tasting both the ingredients going into beer and the finished product. It’s vitally important for hop growers and brewers to be able to identify changes in beers brought on by changes in ingredients, in process, or even in growing conditions. Hop growers even talked about doing sensory analysis of hop cones in the fields to determine when they were ready for harvest. For home brewers and beer drinkers this doesn’t have to go as far as taking sensory training courses (although these can be good fun and a real learning experience); it could be as simple as getting a group of friends together regularly to taste beers and talk or write about your impressions to develop a common tasting language.

The other key theme for me was the matrix effect — how very small changes in one flavour or aroma component within a beer can have a disproportionate effect on how the beer is perceived. Changes to aroma compounds at levels below the threshold for perception can really make other flavours pop. This leads back into the other theme — it’s important to smell and taste your beers regularly to understand how the profile changes with these small tweaks.

What does it mean for drinkers?

The Symposium was very much targeted at brewers and there was a lot of technical information to absorb. The average craft beer drinker is probably not all that bothered about monoterpenes, bound thiol precursors and yeast shmooing (yes, that’s a real word!). However, brewers having more knowledge about the things that drive flavour in beer will inevitably lead to better, more flavourful liquid in our glasses. And the focus on thiols is linked to the continuing voracious demand for juicy, fruity beers — hazies are still the engine driving the craft beer industry and that engine runs on thiols. Finally, climate change is going to put pressure on existing hop growing regions, so the work to expand into new areas is going to be vital if we want to keep drinking our favourite hoppy beverages.