Dry Hopping

Hop Terminology

• Alpha Acid: part of soft resins, main component of bittering. Can make up ~3% to ~14% w/w in the hop.

• Beta Acid: part of soft resins, do not provide much bittering in natural form, some oxidation products contribute a harsh bitterness, parts can be transformed into light stable bittering forms

• Essential oils: (myrcene, humulene, caryophellene, farnesene) Hightly volatile hydrocarbons that typically flash off during boiling. Some of the oxidation products are thought to be positive flavor/aroma contributors. Can make up ~0.5 - ~3mls/100 gram of hops

• Soft resins make up the bittering components (a- & b- acids)

• Essential oils are responsible for the amount and quality of the flavor and aroma (myrcene, humulene, caryophellene, farnesene).

• When writing a recipe we need to balance these two components of hops against each other.

Hop Components

• Hops are typically divided into three types:– Aroma: Goldings, Willamette, Hallertau– Bittering: Magnum, Nugget– Dual purpose: Cascade, Centennial, Columbus

• When creating a recipe think about the quality of the bitterness, flavor and aroma and its appropriateness to the style.

Traditional Hop Additions

• When can we add hops to the wort/beer?– First wort – Beginning/early in the boil– Middle of the boil– End of boil/whirlpool– End of fermentation (dry hopping)– Post filtration

What’s most effective?

• 1 lb/bbl for 50 minutes of post boil kettle residence• 1 lb/bbl for 80 minutes of post boil kettle residence• .5 lb/bbl for 80 minutes of pbk & .5 lb/bbl dry hop• 1 lb/bbl of dry hop only with no kettle addition

• Presumptions: – Kettle hops at the end of boil will increase hop flavor– Increased residence time in contact with hot wort will increase

more “hop character”– Dry hops will create more hop aroma– How does the blend of the two effect flavor and aroma?

Results

• Positive impact on flavor as residence time reaches 90 minutes vs. shorter times – i.e. 60 minutes or less

• Dry hopping clearly improved hop aroma but did not provide good hop flavor

• Best result was from the combination of long residence and dry hopping for flavor and aroma

• Found a relationship between increased hop aroma & hop flavor and perceived bitterness

• Clear negative correlation between sulfate and hop flavor

Factors effecting hop aroma

• Typically use a-acid levels for determining how much hop to use when bittering.

• Need to use essential oil content when determining how much hop to use for aromatic (dry hop) additions

• Essential oil will be variety dependent and vary from harvest to harvest

• Hop selection:– Late harvest typically yields higher a-acid AND

higher essential oil content. – Later harvest can see an increase in essential oils

by 30% – Additionally late harvest hops see an increase

aroma intensity AND aroma quality– This corresponds to increase aroma

intensity/quality in finished beer

Practical / method 1

• Drop in the top • Nucleation / foaming• Dangerous, awkward,

impractical

Practical / method 2

• More user friendly• Longer set up / clean up

time• Better results

Practical / method 3

Practical / method 3

Practical / method 3

• Larger external tank• Flow meter• Pump for mixing

Practical / method 3