hop cultivation, varietal experimentation

The creation of new hop varieties

article written in collaboration with Alexandra Berry

Hops offer a world of possibilities that are increasingly being exploited and improved. Indeed, with more than 300 varieties available on the market - less under the Organic label, as you may have noticed - brewers have the choice! In a world where innovation seems to be a must in the market, new varieties are constantly being developed.

Why create new varieties?

Without varietal development, we would probably not have the fruity bitterness and the Aromatic explosion of American-style IPASthat we have been enjoying in recent years. But the pleasure of the taste buds is not the only motivation for the development of new varieties. Performance is also important in the field, where yields must be high thanks to increased resistance to climatic changes and diseases, greater adaptability to storage, a more concentrated oil content, higher alpha acids, etc. Without forgetting that hops is a historically medicinal plant with therapeutic virtues whose properties are also expected and perfectible.


Understanding hops

The hop(Humulus lupulus) is a flowering plant whose seed has two embryonic leaves. Hops belong to the dicotyledonous family (like roses, apples, strawberries for example) and more precisely to the Cannabaceae family (thus cousin of hemp and cannabis). There are actually three species of hops: Humulus Yunnanensis, H. Japonicus and H. Lupulus, the latter being the species used in brewing.

Hops are dioecious*: they have male and female flowers on separate male and female plants. These flowers are the small hop cones, filled with oils and rich aromas. Hop plants have ten chromosomes, nine of which are autosomes ("normal" chromosomes). The last chromosome will determine the sex of the plant. Indeed, as in the human being, the hop plant has X and Y chromosomes; the plant with an XX chromosome will be female, and XY male. Attention, although we name them identically, the X and Y chromosomes of hops will not be homologous to those of the human being.

*Wild hop varieties are diploid, meaning they have two sets of chromosomes, one inherited from the mother and one from the father. Some commercial cultivars are triploid, meaning they have three sets of chromosomes.



The reproduction of hops

In nature, hops reproduce sexually. Pollen from the male plant - which carries a copy of each of its ten chromosomes - lands on the female cone and fertilizes an egg. The ovule also carries a copy of the chromosomes. The fusion of the pollen and the ovum creates a zygote that contains two copies of each of the ten chromosomes.

This zygote is encapsulated in a seed, which becomes a seedling (a male or female plant) and the cycle continues. The hop plant then produces a rhizome* which are sort of storage stems that can create both the roots and stems of hops. Once the variety has been created, a hop can thus propagate asexually by the lateral growth of the rhizomes.

*Often available for those who wish to plant their hops at home.

To know:

In brewery, only the female plants are cultivated because only these produce the cones concentrating the glands of lupulin. These contain the alpha and beta acids as well as the essential oils for the brewing. The male plants as for them, do not have cones.

Hops plants therefore grow each spring from these rhizomes, which at the time of planting are the size of a finger of the hand. The first set of vines is cut each spring, and the second set that emerges is tied to trellis wires (see article on growing hops).

It usually takes three years for a new hop clone to produce a sufficient, quality crop. The underground rhizome forms a large tangle called a crown. These crowns can be reused to create new hop plants.

Example of a rhizome
Source: https://lameute.beer/produit/plan-de-houblon-en-pot/

Steps to create a new brewery variety

Create the new plant

A new brewery hop variety is the result of a fusion between a female hop plant (often an already known brewery variety) and a male plant that represents a desired characteristic (alpha acid content, high HSI*, favorable yield...). When the female flowers are born, they are bagged to block airborne pollen. Pollen from the male flowers is applied to these female flowers to cause the production of new seeds. These are then planted in greenhouses to germinate.

*preservation and storage capacity.

Source: https://www.beervanablog.com/beervana/2022/6/23/reprise-how-a-hop-earns-its-name

A little science:

Hop plants have a high level of heterozygosity which measures genetic variance. Diploid organisms have two copies of each gene. Each of these copies is called an allele. If an organism has two different alleles for a gene, it is heterozygous for that gene. If the organism has two identical alleles at that locus, it is homozygous.

Hops are heterozygous in that each seed contains a new mixture of alleles. And, although all the plants are obviously the same hop, each is a unique variety of that hop. Thus, if you cross a female Cascade with a male (even with genetic material from Cascade) none of the seeds would yield a plant Cascade.

Plant evaluation

The first year, these plants are grown in greenhouses. All those representing agronomic defects are put aside and those which are preserved are then moved outside. It is necessary to wait for two years of growth in the open air to evaluate their yield, their resistance to diseases... We also evaluate the brewing potential: alpha acid, oil composition etc.

Source: https://www.beervanablog.com/beervana/2022/6/23/reprise-how-a-hop-earns-its-name

Clone evaluation

The rhizomes of validated plants are broken down to produce between 15 and 30 clones. As each one matures, it is evaluated again to ensure that the performance of the seedling applies under all circumstances and that each plant has the same characteristics. The analysis of these properties is done continuously and the successful seedlings are then cultivated on larger and larger plots.

Source: https://www.beervanablog.com/beervana/2022/6/23/reprise-how-a-hop-earns-its-name

Commercial scale testing

In the final stage, some cultivars are finally planted on a plot of about two hectares. The plot must be able to produce enough hops to cover the bottom of a hop drying kiln. The grower then goes through the picking, cone separation, drying and packaging to see if the hops are compatible with commercial scale machinery and packaging. He can already do brewing tests. If everything is validated, the producer then decides if he wants to commercialize this cultivar*.

*Note: to stand out in a market saturated with new hop tests and varieties, each cultivar must have distinct characteristics, making it stand out from a catalog. This can be based on aroma, yield, alpha content, storage capacity, etc.


Source: https://www.gardeningknowhow.com/edible/vegetables/hops/plant-spacing-for-hops.htm

An experimental hop

The most famous example of variety creation would be the Hop Breeding Company, a company working with both Yakima Chief Ranches and Barth Haas*, which produces the experimental hops known as HBC (the company's initials, followed by a batch test number). For example, Citra was originally HBC 394, Sabro was HBC 438, or Mosaic was HBC 369... Hence the interest in highlighting the experimental hops used on certain beers, they can become stars 😉 !

*Jason Perrault of Yakima Chief and Michael Ferguson of Barth Haas are the two hop growers closely involved in this program.

When hops begin to be marketed under the name HBC, this implies that their cultivation has been validated and exploited in commercial form, but that they are still in the experimental phase on the brewing market. Indeed, at this stage, it is necessary to validate the interest of the hops with the brewing industry and their capacity of behaviour through time. The variety will obtain its name after a few years of commercialization, when its interest and its characteristics will have been tested and approved on the field.

Thus, between the production of an initial seedling and its commercialization, it can well take a decade and each clone of a seedling can reach tens of thousands.....

It is important to know that for each new variety marketed, hundreds of semi-hybrids have not been selected.

                                                          Source : https://beerandbrewing.com/terpenes-brewing-with-the-essence-of-hops/

The next time you enjoy a pint of your IPA with a new hop, you'll know that it took years of testing, rejection, and improvement to achieve this result Aromatic !







Hieronymus, S., (2012), For the Love of Hops, The Practical Guide to Aroma, Bitterness and the Culture of Hops, Brewers Publications.

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