Last month I have been living and working on a hop farm in Victoria Australia. I'd like to tell you all a little bit about Hops how they are grown and get to your beer!
Hops are the flower that develop on female hop vines which are grown in paddocks of suspended wire hung vertical from the ground. The hop flowers are generally harvested in early to mid fall. Once ready the hop vines are cut and loaded into trailers and from paddocks to a processing facility on the farm.
We use hops in all beer as a flavoring ingredient, imparting flavors such as pine resin, floral, spiciness, and citrus flavors, and as a preservative. The Germans pioneered hops in beer when it was realized that the preserving attributes of hops were far superior to other previously used bitter plants like dandelion, marigold, and heather.
Here at Rostrevor Hop Gardens the hop varieties grown are Galaxy, Super Pride, Ella Topaz, Vic Secret, and Pride of Ringwood.
Once the hops are picked they are brought to the 'shed' where workers attach the vines to hooks on a conveyor. This suspended conveyor brings them through a threshing machine that separates the leaves and vines from the hop flowers. From there they are loaded by conveyor to the kiln buildings(this is where I worked!)
The kiln is a building where the hops are dried and conditioned. Hops are laid out evenly or 'raked' onto large perforated floors and for about 12 hours, large gas burners heat the hops from below consistently at 60°C. Once the desired moisture is achieved they are dropped onto conveyors to the next building, the pellet plant.
In the pellet plant the dried hop cones drop into a bin where they slowly travel into a grinder that turns them into a fine mulch. They are heated and moistened a touch before entering a circular machine that drives the hot mulch in and pushes it out through small holes about a quarter inch in diameter before they break off and drop into another machine that cools and hardens them. The result are fine rabbit or chicken food like pellets that are then vacuum sealed into bags and shipped to cold storage or brewers.
Most brewers use condensed and dried pellets for brewing as it is easier to maintain consistent Alpha acid content and flavors in the beer then bulked hop counts. It is also cheaper and more efficient to transport boxes of compressed hop pellets to distributors and Brewers.
Hop Science 101
What next? Well first why are the hops flavored and what makes them preserve our beer?
Inside the hop flower our lupulin glands that contain essential oils and resins. Hop resin contains two types of acids, alpha and beta acids, in different levels depending on the variety.
The alpha acids in hops are what impart both flavors and an antibiotic(bacteriostatic) effect. Beta acids react differently and do not affect flavor but instead impart most of the hop aromas in your beer. So depending on your desired result, you may want a variety with more or less of either acid.
Bittering hops tend have much higher alpha acid content then aroma hops(usually, European hops: 5-9% Alpha Acid, and US hops: 8-19% AA)
When making beer hops are added during the "boil" of the wort(wort being beer before it has alcohol content). When you choose to add the hops it is entirely up to you. For a more bitter beer adding bittering hops at the beginning will allow the essential oils to evaporate more leaving Alpha acids behind. Hops added later in the boil or in the fermentation process will impart more aroma to the beer rather than flavor.
That's all I have learnt here and researched on my own time, but working on the hop farm was tough and I learnt a lot. I must say If I took anything away besides money, it would be a thirst for brewing more beer!
W
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