Why Test Hops? To know the  -Acids,  -Acids and Essential Oils Content for: Determining Peak Harvesting Time Blending for Product Consistency Competitive Marketing To know the Moisture Content for: Preparation for Storage To know the Hop Storage Index (HSI) for: Monitoring Changes (Handling & Aging)

A Little Chemistry - I “Bitter Acid”: First isolated from hop cones in late 1800’s Its structure was unknown, but it had some chemical characteristics similar to acids Improved chemistry in early 1900’s revealed there were actually two “Bitter Acids” First called “Alpha Acid” (Greek for “Acid A”) Other called “Beta Acid” (Greek for “Acid B”)

A Little Chemistry – II  -Acids: Improved chemistry in mid-1900’s revealed there were three variations! Humulone Major component (Example: Citra Hops) “Soft” bitter flavor, not “harsh” Cohumulone “Harsher” bitter (some argument about it) Variety high in cohumulone: Brewer’s Gold (US) Adhumulone Smallest component Contribution to bitterness not well understood

A Little Chemistry – III  -Acids (cont.) : Very Poorly soluble in water solutions ~ 0.030% boiling temp. (270 mg/L)  -acids converted into isomerized-alpha acids (Iso-  -acids) By heat and H 2 O during “The Boil” Slowly! (60 – 90 minutes)  -acids also converted into harshly bitter oxidized  -acids with time and temp. Slow but relentless reaction with oxygen

A Little Chemistry – IV  Iso-  -Acids: “Isomer” (Greek) “Iso” = same, “mer” = parts, “isomer” = same parts Same  -acid parts, just rearranged Much more soluble in water solutions About 100 times more soluble than  -acids ~3.0% boiling temp. (270 mg/L) Iso-  -acids are actually the source of bitterness in beer

A Little Chemistry - V  -Acids: Also three variations Lupulone Colupulone Adlupulone  -acids have little bittering capability Even less soluble than the  -acids Do not isomerize into more soluble forms  -acids do convert into oxidized  -acids Much more soluble than original  -acids Are harshly bitter

Just for Fun! Humulone Lupulone  -Acid  -Acid (One of These is Not Like the Other)

Gray = CarbonRed = OxygenLight Blue = Hydrogen Cross your eyes until the two black dots overlap. Focus on the overlapped dots and the rest of the image should come into focus with the side-chains reaching out toward you. (You may have to tilt your head slightly to get the black dots to line up correctly.)

A Little Chemistry – VI Essential Oils: Flavor is strongly influenced by aroma Over 100 flavor/aroma compounds in hop oil Most are at trace levels Fresh Hop Aroma: Linalool, Geraniol, Limonene, Terpineol, Myrcene Noble Hop Aroma: Oxides/Epoxides of Humulene, Caryophyllene, Farnesene Oil component ratios are variety specific Known component ratio can identify variety Known variety can identify component ratio

A Little Chemistry – VII Sweaty/Onion/Garlic Fruit Cocktail Orange Tropical Fruit Grapefruit Melon Green Apple Tutti Frutti (Estery) Rose Floral Apricot/Peac h Green Hop Pine Taste Perceptions Sweaty/Onion/Garli c Apricot/Peac h Melon Tutti Frutti (Estery) “More Floral, Tutti Frutti and Melon Notes” Beer brewed with “Typical” Harvest Cascade Hops “More Sweaty/Onion/Garlic and Apricot/Peach Notes” Beer Brewed with “Late” Harvest Cascade Hops

Chem. Summary Brewers Choose Hop Varieties for: Bitterness (Boiling Hops) Iso-  -acids are primary beer bittering agents  -acids and  -acids have little beer bittering Oxidized (old or abused) hops produce harsh bitterness in beer Aroma/Flavor (Finishing Hops) Oil % composition determines flavor Each variety has a known % composition Age and abuse affect flavor of hops & beer

Determining Harvest Timing

A Tale of Two Farms Williamette Valley, Oregon (MapQuest)

Apples to Apples Farm # Farm #1 Williamette Farm #1 Farm #2 Pre-Harvest Sampling Harvesting Samples Post-Harvest Sampling SeptemberAugust 2010, 2011 Data from Ref (2) Seasonal Effect 2011 harvest is slightly earlier than the 2010 harvest for both farms. Location Effect #2 Farm’s Williamette harvest is 5 days later in both years.

Cascade One of These is Not Like The Other Farm # Williamette Farm #2 Pre-Harvest Sampling Harvesting Samples Post-Harvest Sampling SeptemberAugust 2010, 2011 Data from Ref (2) 6 days Same day in 2010 Now, throw in… Varietal Differences!

What Can We Learn from Harvest Studies? 2002 Data from Ref (1) 2010, 2011 Data from Ref (2) Harvest Dates In Blue AUG SEP

Predicting Harvest Maturity 2002 Data from Ref (1) 2010, 2011 Data from Ref (2) Only if you are harvesting for  -acids Harvest Dates In Blue AUG SEP ✓ ? ? Can  -acid content predict harvest maturity?

Varietal Differences Notice the considerable variation between varieties. The early behavior of one… 2002 Data from Ref (1) 2010, 2011 Data from Ref (2) Date Harvested In Dark Blue …does not predict the later behavior of others. AUG SEP

Getting it Right? Peak Harvest ? How do you know? 2002 Data from Ref (1) 2010, 2011 Data from Ref (2) Date Harvested In Dark Blue AUG SEP

Single Day Harvest? 2002 Data from Ref (1) 2010, 2011 Data from Ref (2) What do you think those early maturing cones look like at harvest, 15 days later? Date Harvested In Dark Blue AUG SEP

Cascade Study Harvest Dates In Blue 2002 Data from Ref (1) 2010, 2011 Data from Ref (2) Properly chosen harvest date? Looks Good AUG SEP  -acid  -acid Oil (x40)

Williamette Study Harvest Dates In Blue 2002 Data from Ref (1) 2010, 2011 Data from Ref (2) AUG SEP Properly chosen harvest date? Hmm…  -acid  -acid Oil (x40)

Can You Judge Maturity on Appearance? 2) Data from Ref (3) ?Test Characteristics vs. Days to Harvest Later harvest is better for Oils

Pre-Harvest Testing Maturation Summary: Know what the brewer wants:  -Acids for bittering Essential Oils for aroma & flavor (finishing) Determine approach to harvest date Peak harvest varies Field to field Season to season Variety to variety Appearance can be deceptive Later is better for finishing hops

Drying Hops

Moisture Content Fresh Hops: Fresh hop cones contain 70-80% moisture by weight Quickly turns to mush: think of “bagged Lilly blossoms” Drying heat oxidizes  -acids and vaporizes oils Good: Less than 140 °F Better: Less than 120 °F Best: Less than 100 °F

Moisture Content Dried Hops: Too Dry- Less than 6% moisture: Cones become brittle, Crumble with handling, Lose resins as “shake-out” and Don’t pelletize as well Goal Moisture Content: 8-10% Too Moist - More than 12% moisture: Prone to spoilage by mold and mildew Potential risk of fire

Yes! FIRE! Spontaneous Combustion: Ironically, in 2006, moist hops caused this fire in a Yakima, WA, warehouse destroying or ruining two million pounds of baled hops, and the 40,000 ft 2 warehouse that contained them.

Why Test Hops? For the Grower: Know the  -Acids,  -Acids and Essential Oils Content for: Determining Peak Harvesting Time Blending for Product Consistency Competitive Marketing Know the Moisture Content for: Preparation for Storage Know the Hop Storage Index (HSI) for: Monitoring Changes (Handling & Aging)

Hop Storage Index & Aging HSI = A nm A nm 0% Oxidized HSI = % Oxidized HSI = % Oxidized HSI = % Oxidized HSI = 2.4

HSI & Freshness Completely Oxidized Fresh Hops

Why Monitor HSI? KNOW Your Product: HSI as indicator of quality Vine Fresh Hops – 0.20 to 0.30 Fresh Dried Hops – 0.20 to 0.40 Moderately Abused Hops – 0.40 to 0.60 Abused Hops – 0.60 to 0.80 Poor Quality, Oxidized Hops – 0.80 to 1.2 Garden Compost Hops – 1.2 to 2.4 HSI does vary slightly with variety and growing conditions – Best to get an initial reading on your harvest each year.

Protect Your Product From: Heat Every 10 °C (18 °F) decrease in temperature roughly doubles the storage life Moisture <6% - Dry, brittle, fragile 8% – 10% - Ideal range >12% - Moisture is catalyst for chemical (and biologically induced) change Oxygen – Reduce Exposure Reduce surface area (compress or pelletize) Protective barrier (impermeable packaging) Remove oxygen (vacuum or inert gas packing)

Monitor and Maintain the Quality of Your Product!

Why Test? Protect Your Investment Large infrastructure investment Large labor investment Market Your Product Known/Certified level of quality Improved negotiating position Grower/Brewer trust REMEMBER… COMPETITION… YOU HAVE...

Large Idaho Hop Farm Elk Mountain Farms At 1700 acres, this is one of the largest hop farms in the world and grows hops exclusively for Anheuser-Busch.

Texas Large-Hop Farm “What we lack in acreage, we make up for in size.”

Rick Cole, Proprietor Midwest Hop and Beer Analysis, LLC 319 Water Street Evansville, WI HOPS (4677)

References 1)Jelle de Keukeleire, Geert Ooms, Arne Heyerick, Isabel Roldan-Ruiz, Erik van Bockstaele and Denis de Keukeleire, Formation and Accumulation of  -Acids,  -Acids, Desmethylxanthohumol, and Xanthohumol during Flowering of Hops (Humulus lupulus L.) 4436 J. Agric. Food Chem. 2003, 51, 4436 − )Daniel C. Sharp, Harvest Maturity of Cascade and Willamette Hops, Master of Science Thesis, Oregon State University, Presented January, ) Murphey, J. M.; Probasco, G. The Development of Brewing Quality Characteristics in Hops During Maturation. MBAA TQ 1996, 33, 149– 159.

Additional Resources arvest arvest nielSharpC2013.pdf?sequence=1 nielSharpC2013.pdf?sequence=1 ers_1 ers_1 us%20 us%20 %20Common%20Hops/Hop%20Anatomy%20and%20Chemistry% html %20Common%20Hops/Hop%20Anatomy%20and%20Chemistry% html (Elk Mountain Farm) anheuser-busch-and-goose-island-bring-a-hop-farm-back-to-life (Elk Mountain Farm) anheuser-busch-and-goose-island-bring-a-hop-farm-back-to-life