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Organic Hops Variety Trials and Over-wintering Study

Hops in the hand


There is great interest among Colorado microbrewers in locally grown hops. The Colorado Department of Agriculture’s Marketing Division conducted a survey and received results from 33 of the 88 microbrewers in Colorado. Thirty of the microbrewers indicated that they would like to be able to purchase Colorado-grown hops, and over half of the surveyed microbrewers were interested in organically grown hops. There is also increasing interest among brewers to make a beer with green or “wet” hops. The production of a wet hop beer would require that the hops be at the brewery within 12 hours of harvest, which would require a local sources of hops.

There is great promise for a hops industry in Colorado. Abundant sunshine and low humidity (which can reduce disease problems) are in our favor. High winds may be a problem in open plains areas since blowing dust could contaminate the lupulin glands. It will also be important to choose varieties that overwinter well. It hasn’t been determined if buyers will require pelletized helps so processing facilities may or may not be required. Such a venture could be cooperatively owned and operated.

Due to the interest in Colorado-grown hops, the CSU Specialty Crops Program is conducting an organic hops variety trial and over-wintering study at the Horticulture Research Center (HRC) northeast of Fort Collins, Colorado. Winter hardiness, alpha and beta acid values, brewing qualities, and yield will be evaluated for several varieties of hops (see below). We hope to collaborate in the future with West Slope research stations and growers to develop baseline hop production information for that region of the state as well.


The hop rhizomes were planted on certififed organic land at the HRC on June 1, 2004, approximately 7′ apart (to keep varieties separate). Six plants each of 10 different varieties were planted for variety trials and two plants each of 4 additional varieties were planted for demonstration. Varieties were chosen based on range of alpha values, maturity times, and those commonly used by microbrewers in Colorado.

We planted “regular” rhizomes. Some companies offer larger” jumbo” rhizomes for planting. The rhizome was planted vertically with the top of the rhizome approximately 1.5″ below the soil surface. A shovel-full of composted manure was mixed in with the soil surrounding the rhizome. The hops were watered with drip irrigation.

The winter of 2005 offered temperatures consistently below freezing with several nights of below zero temperatures providing for a good test of winter hardiness. On May 25, 2005, the hops trellis was built using 14′ long 3″ diamater iron well pipe. The pipe was pounded 4′ into the ground every 20′ in row. High tensile wire was stretched on the top and bottom of the trellis. Baling twine was tied from the bottom to the top in a “v” formation to allow the bines to climb. On June 1, 2005, the plants were trimmed back to 4 main bines. Two bines were guided to each twine. Hops Plants

On June 22, 1-2 gallons of composted dairy manure were applied to the base of each hop plant. Leafhoppers and spider mites, common pests on hops, were present but did not merit control. No powdery mildew was observed on the plants.

Variety Descriptions

Below is a list and description of the varieties being grown for variety trials and demonstration at the HRC.

Est. Alpha Value
Variety Trial Varieties
Canadian Red Vine
vigorous, moderate disease resistance, late maturity, very good yields in the Northwest (2000+ lbs./acre)
medium strength aroma, good yields, med-late maturity, 1800-2200 lbs./acre yields in the Northwest, very commonly used by Colorado microbrewers
good for small brewers, can be used for aroma and bittering, early maturity, same male parent as Nugget, 1430-1700 lbs./acre yields in the Northwest, commonly used by Colorado microbrewers
1800-2400 lbs./acre yields in the Northwest, medium to late maturity, can be susceptible to hop mosaic virus
medium late to late maturity, very good yield 1800-2200 lbs./acre in the Northwest
Mt. Hood
1240-1960 lbs./acre yields in the Northwest, disease resistant, didn’t do well in southern Idaho, commonly used by Colorado microbrewers
high yields, vigorous growth, disease resistant, medium late to late maturity
medium bittering quality, 1500-1900 lbs./acre yields in the Northwest
very good yields in the Northwest (1800-2000 lbs./acre), medium to medium early maturity
potential for high yields, very late maturity
Demonstration Varieties
Brewers Gold
high yielding (2200-2600 lbs./acre) in the Northwest, the father of most current high alpha varieties, not grown in the U.S. after the advent of the super-alpha varieties
classic German aroma hop, used frequently by Busch in premium beers, hybrids have better yields (1000 to 1900 lbs./acre in the Northwest)
medium-early to early maturity, good yields (1100-1780 lbs./acre) in the Northwest
good yields (1200-1600 lbs./acre in the Northwest), medium to medium-late maturity, similar to Hallertauer

Preliminary Observations

Winter survival was very good, 61 out of the 66 hops rhizomes planted in 2004 survived the winter. Canadian Red Vine, Chinook, Cascade, and Centennial were the first to flower on July 6, 2005. Canadian Red Vine, Chinook, and Cascade seemed to produce the most cones during this first year of cone production (2005) based purely on observation. Hop cones were not harvested this year since production was minimal, they will however be harvested in 2006 and tested for alpha and beta acids. Canadian Red Vine hops

Red Vine harvested hops

One plant of Canadian Red Vine (consisting of four bines) was harvested this year just to get a rough idea of yield and it produced 2.18 lbs. of hops wet weight, and 0.57 lbs. dry weight.

The 2002-2003 Grower Grant entitled “Hop Variety Test in Western Colorado” offers more information on growing hops on the West Slope of Colorado near Paonia and gives more yield information on the varieties grown there. Hop research is also being conducted at the CSU Western Colorado Research Center at Orchard Mesa.

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