Nick Carr on December 15, 2018 0 Comments History of Dr. Rudi Hops Dr. Rudi was a product of the New Zealand Horticultural Research Centre’s 1960s and 70s triploid hop research. This research was in response to a widening demand from breweries for seedless hop varieties. To meet this rising demand, Dr. Rudi Roborgh, whom had taken over the New Zealand hop research in 1951, used Colchicine, an alkaloid extracted from autumn crocus plants, to stop cell division and create tetraploid plants from the Calicross, Smoothcone, and First Choice hop varieties. These tetraploid plants had one-third the seeds of regular diploid plants. According to G.S. Wratt and H.C. Smith in their book Plant Breeding in New Zealand, in 1966 the Smoothcone and First Choice plants were open pollinated and the results were triploid plants. A seedling that would become the Dr. Rudi variety was propagated in 1968 as Brand 68-4-96. After the requisite testing and monitoring the variety was released in 1976 under the name SuperAlpha. In 2012, however, the variety was renamed in honor of Dr. Rudi Roborgh. Dr. Rudi has the same Smoothcone tetraploid mother as Green Bullet, another popular variety grown in New Zealand. Earlier this year, Stone Brewing used Dr. Rudi to some acclaim in their Loral & Dr. Rudi’s Inevitable Adventure Double IPA. How to Brew Beer With Dr. Rudi Hops The Dr. Rudi hop variety is not under any sort of protection, so it could be an option for you to grow in your backyard hop garden. However, because it is a New Zealand variety it may be somewhat difficult to find rhizomes or plants for sale in the United States. In the past, Great Lakes Hops has carried Dr. Rudi and is worth keeping an eye on. Also, realize that, if not grown in New Zealand, its terroir — the environment in which it is grown — may change its aroma and flavor profile to varying degrees. Acid Composition Breakdown Alpha Acid: 10 – 12% Beta Acid: 7 – 8.5% Co-Humulone: 33% Oil Composition Breakdown Total Oils: 1.3mL/100g Myrcene Oil: 29.2% (of total) Humulene Oil: 33.2% (of total) Caryophyllene Oil: 10.1% (of total) Franesene Oil: 0.5% (of total) B-Pinene Oil: ? Linalool Oil: 1.4% (of total) Geraniol Oil: ? Hop oil composition will vary between harvest years and where the hop was grown. These numbers represent an average only. Of course, before you attempt to grow your own hops, it would be wise to talk to other local growers in your area to ensure that you have a better understanding of what varieties will grow well in your area. General Characteristics: Origin — New Zealand Year Released — 1976 Growth Rate — Vigorous, good climber; may require more spacing between plants due to length of side arms Yield — Moderate; Ranging from 1000-1800 lbs/acre Cones — Long Compact Cones Maturity — Mid Season (late season in the U.S. : not recommended for places with a short growing season) Susceptible / Resistant To — New Zealand does not have any hop diseases, but grown in the U.S. Dr. Rudi shows improved resistance to downy mildew than Pacific Gem Ease of Harvest — Good Storage — Medium; Retains 60% – 70% alpha acid content after 6 months storage at 68°F Patented or Public — Public Aroma & Sensory Description: Dr. Rudi is described as having a soft to moderate floral aroma along with a fresh pithy citrus bite. Possible sidelines into lemon and some mellow fruitiness. Other notes often said to be expressed include pine needles, resin, herbal/spicy elements, and lemongrass. Bittering is considered crisp and clean. Availability: Dr. Rudi hops are easy to find in pellet form. Your local homebrew supply may even have them in stock. As with many imported hops, they are almost impossible to find in other forms, such as whole cone. If you are having trouble locating Dr. Rudi hops, try searching for the variety under their old name SuperAlpha. Some online homebrew shops may still use the old name. Use: When first released Dr. Rudi was branded as a high-alpha bittering hop. However, its oil profile has lent it favor as a dual-purpose hop and is now largely marketed as such. Used early in the boil it contributes a resinous, yet crisp bitterness with pithy hints of citrus. It works well as a single hop choice especially when looking for mellow fruit and herbal character. It is also often used to “round out” aroma varieties creating a more complex and fully realized flavor/aroma range. Dry hopping brings out more of the herbal and citrus with possible sweet grassy notes, depending on quantity used. Can Substitute With / For: Unfortunately, I’m not sure there’s a clear, halfway decent substitute for Dr. Rudi. The oil profile, according to Scott Janish’s hop oil calculator (this is a fun calculator to play around with if you get the chance) the variety is most similar to is the German Perle variety. Another Possible Substitute: Green Bullet Beer Styles That Use Dr. Rudi Hops Pale Ale & IPA Lagers Pilsners Australian Sparkling Ale Blondes Doppelbock English Bitters Sours Winter Ales Commercial Examples: To help you gain a better idea of this hop’s aroma and flavor I would recommend you sample as many of these as you can find. This, ummm… research will deepen your understanding of how Dr. Rudi works in different beer styles and give you a better idea of how to use it in your own homebrewing. Uses Only Dr. Rudi: Jack of Spades from James Squire Brewing (Australia) Dr Rudi from Rockhopper Brewing Company (UK) Dr Rudi Pale Ale from Newcastle Brewing Ltd. (UK) Dr Rudi from Bingley Brewery (UK) Uses Dr. Rudi With Other Hop Varieties: Mai from Matutu Brewing Company (NZ) — Also uses Hallertau and Saaz Four Wives from James Squire Brewing (Australia) — Also uses Czech Saaz and Motueka No. 1 Pale Ale from Rockhopper Brewing Company (UK) — Also uses Cascade Hay-Z IPA from Temblor Brewing Company (USA) — Also uses Vic Secret Cricket IPA from Firefly Hollow Brewing Company (USA) — Also uses CTZ If you have any experience brewing with Dr. Rudi hops or have tasted beer that make use of the variety, please let everyone know what your thoughts are down in the comments below. Happy Brewing!
