Liquid hop products have been a major innovation in the industry, delivering brewers more tools to play with when it comes to designing and optimising beers from a sensory and yield perspective. Here Andy Parker the author, award-winning brewer, and founder of Elusive Brewing, shares his experiences of working with such products at the Berkshire-based brewery.

Liquid hop aroma products are far from a new development. Back in 2016, when Elusive started, the perpetually in demand modern hop varieties such as Citra and Mosaic were not available on the spot market, so we turned to Barth Haas’ PHA products to help add those top notes to some of our early brews.

This helped stretch the small quantity of those desirable varieties we could get our hands on a little bit further and also set us down a path of experimenting with less in demand varieties, soon discovering that blending hops could produce an aroma greater than the sum of its parts. 

Over the past 3-5 years, liquid hop products have been a key area of innovation within the industry, driven by a demand for ever more intense aroma and flavour with a keen eye on hot and cold side yield.

In a modern craft brewing landscape where consumers demand high levels of hop impact, packaged yields are going down and per-litre production costs are going up.

At Elusive, the style of beers we brew are hop forward but not often intensely so by modern standards. Our best seller Oregon Trail is hopped at around the equivalent of 13g/L (grams per litre), split evenly across hot and cold side additions.

Over the past 18 months, we’ve experimented with just about every liquid hop product on the market, with two aims: 1) explore how much hot side intensity we could impart into our West Coast-style IPAs and Pale Ales without access to anything other than a very rudimentary whirlpool and 2) increase the packaged yield to deliver as high a sales margin as possible from each gyle.

Whilst we are able to liquor back and fill fermentors to the brim with the aid of a hop-derived antifoam, reducing solid matter in the form of dry hop additions without compromising on aroma or depth of flavour was key to help us package more beer from the same tanks. 

Focusing first on the hot side, there are several hop varietal specific products designed for use in the kettle or whirlpool, fully or partially replacing the use of whole cone or pellet hops in this application.

“In our case, we’ve been able to achieve very positive results in terms of finished beer quality whilst increasing packaged yield.”

Andy Parker, Elusive Brewing

These include Barth Haas (Haas) Incognito, Totally Natural Solutions (TNS) HopGain Floe and Yakima Chief Hops (YCH) Dynaboost. Their specific production methods are proprietary but involve CO2 extraction of volatile aroma oils into a substance that has varying degrees of flowability across each product.

The liquids are supplied in 1-2Kg tubs and the suppliers claim each kilogram is the equivalent to using 6Kg (Haas) and 10Kg (YCH) of T90 pellets. TNS suggests an initial dosing of 1/10th the weight of T90 but doesn’t state an equivalent weight as the oil content has been standardised, so this will vary depending on the hop variety.

All three suppliers advise that the product is best dissolved into hot wort and whirpooling is recommended to ensure a good mix. We found the TNS product was flowable enough to pour directly into the copper from the fridge but the YCH and especially the Haas products became more flowable having been warmed slightly. 

If increasing hot side yield is your aim, these products can be helpful – especially if you’re using whole cone hot side, as losses caused by doing so can be significant. Whole cone hops can hang onto as much as 5 litres of wort per kilogram added, five times the volume that pellet slurry will absorb.

To get the most out of these products, it’s recommended to whirlpool for a sufficient amount of time and with sufficient velocity to fully dissolve them. We found in practical use that all left a degree of oily residue in the kettle – nothing that couldn’t be shifted through CIP or a bit of elbow grease.

As well as aroma oils, Incognito and Dynaboost contain a high concentration of alpha acids, so wort temperature is also a consideration if the aim is to minimise isomerisation and bitterness. TNS have stripped the alpha acids from HopGain Floe, so this can be added directly post boil.

We’ve had good success with these whirlpool products but perhaps the best results, given our lack of vigorous whirlpool, have been from using them via a ‘hop dipping’ method whereby they are dissolved in a jug with hot wort and a small amount of pellets, then dosed straight into the fermentor at the start of transfer, with the initial wort being cast in hot before the temperature is reduced as transfer progresses until pitching temperature is reached.

This method ensures good even mixing and prolonged contact time during active fermentation. For us, cleaning was also more efficient as our Unitanks are much easier to clean via CIP than our kettle.

Our own trials suggested that, using this method, we ended up with more flavour and aroma being present post fermentation (before dry hopping) when using all liquid – or a mix of liquid and whole cone – than we did from just using whole cone at equivalent weights. 

Moving onto products aimed at cold side additions, Haas (Spectrum), TNS (HopBurst) and YCH (Hyperboost) all have varietal specific offerings and these are joined by products from FreeStyle Hops (SubZero Hop Kief) and Abstrax (Quantum Series – available from Charles Faram), to create quite the choice for the brewer. The intensity of these products by volume varies across the board, so it’s recommended to refer to their datasheets for dosing advice.

Haas recommends that Spectrum, which is more viscous than other products in this class, is added a few points off final gravity so that the active fermentation naturally mixes it into the near finished beer. Other products can easily be dosed post-fermentation.

The key is getting them dispersed well to maximise the aroma gained and ensuring that dosing is optimised to achieve the required intensity. We’ve found that adding them along with the auxiliary finings works well followed by rousing, with the tank temperature reduced and yeast and dry hop matter already dropped out.  

We’ve had the best results from a sensory perspective when replacing between 25% and 50% of the equivalent T90 addition with liquid products.

However, we did try brewing a beer that used 100% liquid hop products, in collaboration with TNS, and both our own sensory and consumer feedback was positive. There’s likely a trade-off between true-to-type sensory results and yield here, however. 

It’s clear that the continued innovation in this space has delivered brewers more tools to play with when it comes to designing and optimising beers from a sensory and yield perspective.

In our case, we’ve been able to achieve very positive results in terms of finished beer quality whilst increasing packaged yield, significantly so when using these liquid products in combination with super-concentrated hop pellet products such as Crosby Hops CGX, Haas LupoMAX or YCH Cryo Hops in a blend with T90 pellets.

On completion of our project to optimise yield, we’re now packaging an extra three 30L kegs of Oregon Trail per 17HL batch, with no negative sensory impact.

The associated extra revenue per batch more than offsets the increased cost of ingredients too, so it’s actually costing us less per litre to produce in real terms.

Andy Parker is owner and head brewer at award-winning Berkshire-based Elusive Brewing and was named the British Guild of Beer Writers Brewer of the Year in 2022. He co-authored CAMRA’s Essential Home Brewing book and champions the vibrant British homebrewing scene from where his love of beer and brewing developed. Last September, his latest book The Modern Homebrewer was published. Co-authored with Jamil Zainasheff, it’s a hands-on, practical guide to the most modern and up-to-date home brewing ingredients, equipment, and processes. The book equips both novices and the most experienced brewers with the skills they need to produce professional quality beer at home.