Hops

Question 1

What are the parts of the hop cone?

Answer 1

Central strig, 2 bracts, 4 bracteoles
Seeds, Achene (fruit and seed), Lupulin glands

Question 2

Total resin percentage of hop cone

Answer 2

15-30%

Question 3

Essential oils percentage of hop cone

Answer 3

0.5-3%

Question 4

What are the hop breeding methods?

Answer 4

Selective breeding and cross breeding

Question 5

Where are hops indigenous?

Answer 5

Europe, Asia and North America

Question 6

Best latitudes for hop growth

Answer 6

34-55th parallel (for period of light)

Question 7

What are the major types of hop pests?

Answer 7

Damson hop aphid (yields, mold, browning), Red spider mite (silver speckling and webbing, loss of crop)

Question 8

What are the major hop diseases?

Answer 8

Powdery mildew (loss), Downy mildew (Stunted shoots), Verticillium Wilt (yellow/black, spreads), Hop Mosaic virus (stunting, loss, low acid), Hop latent virus (acid decrease), Necrotic ringspot virus (major cone and acid decrease)

Question 9

What is the typical timeline (N hemisphere) for first hop shoots, full height and harvest?

Answer 9

April, mid-end July, End of August-Late September

Question 10

Hop moisture at harvest

Answer 10

75-80%

Question 11

Hop kiln temp and moisture specs

Answer 11

Kiln at 65 C, moisture decrease from 80 to 10%

Question 12

What part of hop plant holds the total resin and essential oil?

Answer 12

Lupulin

Question 13

What part of the ho cone holds the Polyphenols?

Answer 13

Bracts/Bracteoles

Question 14

What comprises soft resins?

Answer 14

Alpha acids, Beta acids, uncharacterized components

Question 15

What are the three homologs of alpha acids?

Answer 15

Humulone, cohumulone and Adhumulone

Question 16

What are the three homologs of Beta acids?

Answer 16

Lupulone, Colupulone and Adlupulone

Question 17

What are the 3 isomers of isomerism hops?

Answer 17

Cis or trans

Question 18

What salts are used to pre-isomerize hops?

Answer 18

Magnesium or potassium

Question 19

What homolog has the highest solubility and utilization?

Answer 19

Cohumulone

Question 20

What is typical hop utilization in typical brewing process

Answer 20

30-35%

Question 21

What factors (13) affect hop utilisation?

Answer 21

pH, Boil time, Wort gravity, Trub, Temperature, Pressure, Hop age, Hop product, Quantity of hops, Wort boiling system, Hop alpha acid level, Wort composition, Foaming

Question 22

What are oxidized alpha acids?

Answer 22

Humulinones (66% as bitter)

Question 23

What consists of most of hard resins?

Answer 23

Xanthohumol (Beta hard resin)

Question 24

What % of polyphenols in beer come from hops?

Answer 24

20-30, sometimes higher if dry hopped

Question 25

How can polyphenols benefit beer stability?

Answer 25

They are antioxidants, acting as free radical scavengers and chelating metal ions

Question 26

Polyphenol groups

Answer 26

Flavanols, Flavan-3-ols, Phenolic carboxylic acids, Other

Question 27

Three categories of Hop essential oils

Answer 27

Hydrocarbons (50-80%), Oxygenated (20-50%), Sulphur (<1%)

Question 28

What are the major hydrocarbon aromatics called?

Answer 28

Terpenes (terpenoids)

Question 29

Notable hop hydrocarbons

Answer 29

Beta-myrcene (mono 30-70%), Alpha and Beta-Pinene (mono), Alpha-humulene, Beta-caryophyllene, Beta-farnesene

Question 30

Six types of hop oxygenated oils

Answer 30

Esters, alcohols, Aldehydes, Acids, Ketones, Epoxides

Question 31

Notable hop oxygenated oils

Answer 31

Linalool, geraniol, citranellol, hexanal, Undecan-2-one, methyl

Question 32

What temp are T45 pellets hammer milled?

Answer 32

-35 C

Question 33

What moisture are T90/45 hops dried to?

Answer 33

6%

Question 34

What are the main varieties of non-isomerized pellet hops?

Answer 34

T100, T90, T45, BBC Pure Hop Pellet, Cryo/CGX

Question 35

Typical utilization between T90 and T45 hops?

Answer 35

27-32% vs 35%

Question 36

What are the solvents used in hop extract?

Answer 36

Ethanol or CO2

Question 37

What property of hop extract solvents is important for extraction?

Answer 37

Polarity

Question 38

What hop components does ethanol extract from hops?

Answer 38

Soft and hard resins, essential oils, polyphenols

Question 39

What are the typical steps for hop extract production?

Answer 39

Break bales Sieve Wet mill Extraction Centrifuge/Filter Evaporator Distillation Column Separate resin extract from tannin

Question 40

Typical utilization of non-isomerize hop extracts

Answer 40

35-40%

Question 41

What compound is used to catalyze pre-isomerized hops?

Answer 41

Magnesium oxide

Question 42

What is typical utilization of pre-isomerized hop pellets?

Answer 42

65%

Question 43

What are the 6 types of isomerize hop extracts?

Answer 43

Isomerized kettle extract (IKE) Isomerized hop extract (iso-extract) Hydrogenated/reduced hop extracts Rho-hydro iso-extract Tetra-hydro iso extract Hexa-hydro iso-extract

Question 44

When is iso-extract best added?

Answer 44

Post-fermentation

Question 45

What is lightstruck flavor?

Answer 45

3-methyl-2-butene-1-thiol Light-induced reaction involving riboflavin (photosynthesiser), a sulphur compound and isohumulone.

Question 46

What are reduced hop extracts?

Answer 46

chemically changed by reducing the unsaturated bonds on the side chains that can be affected by UV light. UV light removes the side chain the iso-a-acid which reacts with sulphur free radical

Question 47

What are the three types of reduced hop iso-extracts?

Answer 47

Rho, Tetra and Hexa

Question 48

What are the main processes involved with hop aroma product extraction?

Answer 48

Steam and vacuum distillation, thin film evaporation, CO2 fractionation, chromotography

Question 49

What can cause silver/brown spots on hops?

Answer 49

mildew

Question 50

What can cause black coloration on hops?

Answer 50

Mold due to aphids

Question 51

What can cause red color on hops?

Answer 51

Spider mites

Question 52

What methods are available for measuring hop a-acid content?

Answer 52

-Lead conductance value -UV light absorbance spectrophotometry -High pressure liquid chromatography

Question 53

What methods are available for measuring hop essential oil content?

Answer 53

-Total essential oil analysis by steam distillation -Gas chromatography with flame ionization detection (GCFID)

Question 54

What wavelength of UV light is used to measure a-acids?

Answer 54

325 nm

Question 55

What wavelength of UV light is used to measure b-acids?

Answer 55

355 nm

Question 56

What wavelength of UV light is used to measure background absorbance of a and b-acids?

Answer 56

275 nm

Question 57

What are the three process considerations in hop dosing automation?

Answer 57

Preparation of addition Measuring quantity and transfer Dosing into wort