unit 4 lesson 2 Flashcards
1
Q
What is the main reason we use hops in brewing?
A
To provide flavour.
2
Q
What is the botanical classification of commercially cultivated hops?
A
Humulus lupulus L.
3
Q
What part of the hop plant is the hop cone?
A
The fruit bearing part of the plant.
4
Q
What are the two basic groups of hop varieties?
A
- Bittering or high α-acid varieties
- Aroma varieties
5
Q
True or False: Hops can be used for both bittering and aroma.
A
True.
6
Q
Why are seeded hops typically not used for in brewing?
A
Due to the seeds’ high fatty acid content.
7
Q
Hops are dioecious, what does this mean?
A
That the plant is a either male or female
8
Q
What is the role of the hop breeding programme?
A
To develop new hop varieties.
9
Q
What is the typical time frame for a new hop variety to reach the market?
A
10-20 years.
10
Q
What must hop breeders consider when developing new varieties?
A
- Pest or disease susceptibility
- Yields
- Desirable aroma levels
11
Q
What is the primary function of the lupulin glands in hops?
A
To produce bitter and aromatic compounds.
12
Q
What are the effects of hops added at the start of wort boiling?
A
Impart characteristic bitterness.
13
Q
What do hops added during fermentation or maturation provide?
A
Aroma but very little bitterness.
14
Q
What is the average composition of total resins in a hop cone?
A
15-30%.
15
Q
How does the presence of male hops affect female hops?
A
They can cause unwanted pollination.
16
Q
What are the main types of hop pests?
A
- Damson-hop aphid
- Red spider mite
- Powdery Mildew
17
Q
What is the significance of vernalisation in hops?
A
It is required for hops to flower.
18
Q
Fill in the blank: Hops need a specific period of daylight, typically found between the ______ and ______ parallel of latitude.
A
34th, 55th
19
Q
What do farmers use to support the climbing hop plants?
A
Tall trellises with wooden support frames and wires.
20
Q
What is the main effect of the damson-hop aphid on hops?
A
Low yields and spoiling cone appearance.
21
Q
What characteristics do hop breeders look for in new varieties?
A
- Disease resistance
- High yields
- Desirable aroma
22
Q
True or False: New hop varieties are often developed to have improved resistance to diseases.
A
False.
Brewers often seek novelty, requiring a flow of new varieties. Some new hop breeding programs focus less on developing improved resistance to disease or high yields, leading to varieties that may not be grown extensively or remain available for many years. The intent is often to replace them within two to three years.
23
Q
What is the main effect of the Damson-hop aphid on hops?
A
Low yields, sooty mould fungus grows on the aphid honeydew, spoiling cone appearance and can cause cones to turn brown.
The aphid secretes honeydew, which leads to the growth of sooty mould on hops.
24
Q
What damage is caused by the Red spider mite?
A
Silver speckling and webbing on leaves and cones, leading to reddish brown cones and crop loss.
The presence of webbing indicates a significant infestation.
25
What are the symptoms of Powdery Mildew?
White powdery spots on leaves and stems, which can turn red if untreated, causing serious losses if cones become infected.
## Footnote
This is a fungal disease that thrives in certain environmental conditions.
26
What effect does Downy Mildew have on hop plants?
Causes stunted shoots and laterals, resulting in serious reduction in vegetative growth and cone losses.
## Footnote
It is caused by a specific fungus affecting the plant's growth.
27
Describe the initial symptoms of Verticillium Wilt.
Yellow patches on hop leaves that become black as the tissue dies.
## Footnote
This disease spreads rapidly once a field is infected.
28
What are the key symptoms of Hop Mosaic Virus?
Severe stunting of bines, translucent banding along veins, curling leaves, loss of cone yield, and drop in α-acid content.
## Footnote
This is a viral disease impacting hop quality and yield.
29
What is the suggested impact of Hop Latent Virus?
May reduce α-acid content.
## Footnote
This virus can be asymptomatic but still affect the quality of hops.
30
What symptoms are associated with Necrotic Ringspot Virus?
Chlorotic rings or arcs that can become necrotic, with cones and α-acids reduced by up to 50%.
## Footnote
This highlights the significant yield loss potential from viral infections.
31
What is the first step in starting a new hop garden?
Consider propagation methods such as layering, mist propagation, or taking cuttings.
## Footnote
These methods ensure healthy plants for growth.
32
What types of hop varieties can be selected?
* Aroma variety
* Bitter variety
* Traditional variety (up to 7 m)
* Dwarf variety (up to 2-3 m)
## Footnote
The choice of variety influences growth requirements and harvest timing.
33
What is the typical soil pH required during the growth phase of hops?
Around 6.5.
## Footnote
Proper soil pH is crucial for nutrient uptake in hop plants.
34
When do hops typically reach full height during the growing cycle?
By mid-to-end July.
## Footnote
This is also when lateral growth begins to occur.
35
How are tall hops typically harvested?
By cutting the whole bine, including the string, and taking them to the hop picking machine.
## Footnote
This method is efficient for large-scale operations.
36
What moisture content should hops have at the time of harvest?
Between 75-80%.
## Footnote
Harvesting at this moisture level helps maintain quality.
37
What temperature is used to dry hops in a hop kiln?
65°C.
## Footnote
This process reduces moisture from 80% to 10%.
38
What is the purpose of conditioning hops?
To even out moisture levels within the cones and throughout the batch.
## Footnote
Proper conditioning prevents combustion in storage.
39
True or False: Hops are harvested when they are fully mature.
False.
## Footnote
They are harvested during growth to maintain optimal quality.
40
What are the key steps in hop production?
* Identify required hop types
* Breed hops to meet needs
* Propagate, plant, and grow
* Harvest, dry, and stabilize hops
## Footnote
Each step is critical for successful hop cultivation.
41
Fill in the blank: Hops are perennial, meaning they _____.
[grow back each year]
## Footnote
This characteristic influences the growing cycle and management practices.
42
What is the significance of oil content in hops?
Determines aroma and quality for brewing.
## Footnote
The composition of the oil changes as the cone matures.
43
What happens to the hop plant parts above ground towards winter?
They die and are pruned back.
## Footnote
Nutrients move to the rootstock for the next growing season.
44
What is an Achene?
The fruit of the hop that contains the seed, similar to the pips on a strawberry.
45
What are α-acids?
Bitter compounds found in hops that contribute to the bitterness of beer.
46
What are Aroma Hops?
Hop varieties used primarily for their aromatic properties, typically with lower α-acid content.
47
What is a Bine?
The stem of the hop plant, which wraps around supporting structures in a helix.
48
What are Bittering Hops?
Hop varieties used primarily to impart bitterness to beer, typically with higher α-acid content.
49
What is a Bract?
Leaf-like structure attached to the central strig of the hop cone.
50
What is a Bracteole?
Smaller leaf-like structure attached to the central strig of the hop cone.
51
What is the Cannabinaceae Family?
The plant family that includes hops (Humulus lupulus L.) and cannabis.
52
What is Clonal Selection?
A breeding method where the best and most robust plants are selected for propagation to maintain purity of a single variety.
53
What is Colloidal Stability?
The ability of beer to remain clear and free from haze over time.
54
What is Crossbreeding?
A breeding method where different varieties with desirable attributes are selected to produce hops with the desirable attributes of both.
55
What is Dry Hopping?
The process of adding hops during fermentation or maturation to impart aroma without adding significant bitterness.
56
What are Dual-Purpose Hops?
Hop varieties that possess both desirable aroma and good bittering potential.
57
What are Essential Oils?
Aromatic compounds found in hops that contribute to the aroma of beer.
58
What is a Hop Back?
A vessel used in brewing to filter wort through hops, adding flavor and aroma.
59
What is a Hop Cone (Strobilus)?
The fruit-bearing part of the hop plant, consisting of a central strig with bracts and bracteoles attached.
60
What is a Hop Kiln?
A drying facility where hop cones are dried using warm air to reduce moisture content.
61
What is a Hop Picker?
A machine used to separate hop cones from the bines during harvest.
62
What is a Hop Variety?
A specific type of hop plant with unique characteristics, such as α-acid content and aroma profile.
63
What is the scientific name for the hop plant?
Humulus lupulus L.
64
What does IBU stand for?
International Bitterness Units.
65
What are Lupulin Glands?
Glands within the hop cone that produce bitter and aromatic compounds used in brewing.
66
What is Mist Propagation?
A method of propagating hop plants by maintaining a mist of fine water droplets over cuttings to stimulate root growth.
67
What are Pectins?
Polysaccharides found in hops that can affect the brewing process.
68
What is a Perennial Plant?
A plant that lives for more than two years and does not need to be replanted annually.
69
What are Polyphenols?
Compounds found in hops that affect flavor, colloidal stability, and mouthfeel of beer.
70
What is Propagation?
The process of growing new hop plants from cuttings, layering, or seeds.
71
What are Resins?
Bitter compounds found in hops that contribute to the bitterness of beer.
72
What is Selective Breeding?
A breeding method where the best and most robust plants are selected for propagation to maintain purity of a single variety.
73
What is Strobilus?
Another term for the hop cone, the fruit-bearing part of the hop plant.
74
What is a Trellis?
A framework used to support the growing hop plant.
75
What is Vernalisation?
The process of exposing plants to low winter temperatures to encourage dormancy and flowering.
76
What are hops primarily used for in brewing?
To provide flavor
## Footnote
Hops also have antimicrobial properties and contribute to foam, colloidal, and flavor stability.
77
What is the scientific classification of commercially cultivated hops?
Humulus lupulus L.
## Footnote
Hops belong to the Cannabinaceae family, which also includes cannabis.
78
What do hop cones contain that is crucial for beer flavor?
Chemical compounds
## Footnote
The hop cone is the fruit-bearing part of the hop plant.
79
What are the two main types of hop varieties used in brewing?
Bittering varieties and aroma varieties
## Footnote
Bittering varieties impart characteristic bitterness, while aroma varieties provide aromatic properties.
80
What is the impact of the timing of hop additions during brewing?
Affects bitterness and aroma
## Footnote
Hops added at the start of wort boiling impart bitterness, while those added during fermentation provide aroma.
81
What are the typical α-acid values for aroma hops?
Below 10%
## Footnote
Bitter varieties have α-acid content above 10% and can have a strong aroma.
82
What are the key stages in a hop breeding program?
Creating crosses, raising seedlings, assessing for aroma, selecting varieties, and commercial propagation
## Footnote
This process can take 10-20 years.
83
What is the importance of lupulin glands in hop cones?
Produce bitter and aromatic compounds
## Footnote
These compounds are essential for brewing.
84
What are common challenges faced by hop growers?
Climate, day length, pests, and diseases
## Footnote
Common pests include damson-hop aphid and red spider mite.
85
What is the ideal moisture content for hops at harvest?
75-80%
## Footnote
Hops must be harvested within 10 days of ripening to prevent over-ripening.
86
What is the purpose of drying hops after harvesting?
To reduce moisture content and prevent deterioration
## Footnote
Hops are typically dried to 10% moisture.
87
What is the role of conditioning hops?
To even out moisture levels
## Footnote
Conditioning occurs at 20-24°C with 58-65% relative humidity.
88
True or False: Male hop plants are kept on farms to encourage pollination.
False
## Footnote
Male plants are destroyed to prevent unwanted pollination.
89
Fill in the blank: Hops are _______ plants, meaning they produce either male or female flowers.
dioecious
90
What is the typical growing cycle for hops in the Northern Hemisphere?
Begins in March, with harvesting from late August to September
## Footnote
Plants can grow up to 30 cm per day during the active growing period.
91
What are the effects of pests and diseases on hop plants?
Reduce yields, spoil appearance, and affect α-acid content
## Footnote
Diseases include powdery mildew and hop mosaic virus.
92
What factors influence the popularity of hop varieties?
Brewer, grower, and trader benefits
## Footnote
Traits such as pest resistance and high yields are desirable.
93
What is the typical temperature used for drying hops in a hop kiln?
65°C
## Footnote
This temperature reduces moisture from 80% to 10%.
94
What must be balanced when determining the optimum harvest time for hops?
Yield, α-acids, oil content, appearance, and aroma
## Footnote
There is no single optimum harvest time due to these variables.
95
What is the purpose of tall trellises in hop cultivation?
To support climbing hop plants
## Footnote
Hops are perennial plants that live for more than two years.
