Unit 2 - Lesson 8 - Yeast Flashcards
1
Q
What is the husk?
A
The dry outer layer that covers the kernel, consisting mainly of cellulose and lignin
The husk protects the embryo and forms a filter bed during wort separation in distillation. Almost all cereals have a husk except sorghum.
2
Q
What is the primary role of the husk?
A
To protect the embryo inside from physical damage
It also forms a filter bed during wort separation in the distillery.
3
Q
What is the function of the pericarp?
A
To restrict water uptake
It is located just below the husk.
4
Q
What is the function of the testa?
A
To limit water uptake and prevent nutrients from leaving the grain
The testa has a waxy coating.
5
Q
What does the term ‘scutellum’ mean in Latin?
A
‘Shield’
6
Q
What is the role of the scutellum?
A
Enables nutrient movement between the endosperm and the embryo
7
Q
What is the role of the aleurone layer?
A
To secrete enzymes into the endosperm
These enzymes help break down starch, protein, and cell walls into nutrients for the embryo.
8
Q
What is stored in the embryo of the barley grain?
A
Nutrients such as lipids, sucrose, and proteins
These nutrients allow the embryo to grow before nutrients from the endosperm are available.
9
Q
What is the endosperm?
A
The bulk of the barley kernel and the main source of food for the embryo
It consists of cells made with cell walls of β-glucans, pentosans, and proteins.
10
Q
What is the main storage carbohydrate in cereal endosperms?
A
Starch
Starch serves as an energy source for the developing plant.
11
Q
What does starch consist of?
A
Chains of glucose molecules
Yeast cannot ferment starch directly.
12
Q
What must happen to starch during the malting process?
A
It needs to be broken down into sugars
This is facilitated by barley enzymes.
13
Q
What can happen if β-glucans in the endosperm cell walls are not broken down?
A
Wort separation problems in the distillery
Proper breakdown is crucial for the malting process.
14
Q
What are endosperm proteins broken down into during malting?
A
Amino acids or free amino nitrogen (FAN)/yeast assimilable nitrogen (YAN)
These components are used by yeast for growth during fermentation.
15
Q
What are the most common cereals used in distilling?
A
Maize (corn), wheat, rye, sorghum, rice, and barley.
16
Q
What is a key requirement for bourbon production?
A
Must be made from more than 51% maize (corn).
17
Q
What factors should be considered when choosing a cereal for distilling?
A
Product type and legislation, availability, cost, GMO status, ease of processing, flavour, and enzymes.
18
Q
Why do distilleries consider local availability of cereals?
A
To minimise production costs and environmental impact.
19
Q
What happens if the cost of a cereal is too high?
A
We may not be able to make our spirit economically.
20
Q
What is the significance of GMO cereals in distilling?
A
Some countries allow their use, while others ban them, affecting distillers’ choices.
21
Q
What processing capability must distilleries have regarding cereals?
A
They must purchase cereals they can process, such as malted cereals.
22
Q
What flavour does rye contribute to spirits?
A
A spicy flavour.
23
Q
What role do malted cereals play in distilling?
A
They serve as a source of enzymes to convert starch into sugar.
24
Q
What is an enzyme?
A
A catalyst of biological origin that helps chemical reactions to occur more easily.
25
What is the primary family classification of maize?
Poaceae (grass family)
## Footnote
This family includes various grasses and cereals.
26
What is the genus of maize?
Zea
## Footnote
This is the taxonomic genus that includes maize and other related plants.
27
What is the species name of maize?
Zea mays
## Footnote
This is the scientific name used to identify maize specifically.
28
In what type of climates is maize predominantly grown?
Warm, temperate climates
## Footnote
These conditions are favorable for the growth of maize.
29
What are the main uses of maize?
Food, animal feed, and in beverages
## Footnote
Maize is versatile and serves multiple purposes.
30
Why is maize popular in distilling?
It has a large endosperm and is a good source of starch
## Footnote
The starch content is crucial for fermentation processes.
31
What percentage of the dry weight of a maize kernel is made up by the endosperm?
71-80%
## Footnote
This high percentage highlights the significant starch content in maize.
32
What percentage of the dry weight of a maize kernel is made up by the embryo?
10-15%
## Footnote
The embryo is the part of the seed that develops into a new plant.
33
What family does wheat belong to?
Poaceae (grass family)
## Footnote
The Poaceae family is commonly known as the grass family, which includes many species important for agriculture.
34
What is the genus of wheat?
Triticum
## Footnote
Triticum is the genus that encompasses various species of wheat.
35
What species of wheat is commonly cultivated?
Triticum aestivum
## Footnote
Triticum aestivum is known as common wheat and is widely grown for food.
36
What climates are suitable for growing wheat?
Warm, temperate climates
## Footnote
Wheat thrives in climates that are not too hot and not too cold, allowing for a good growing season.
37
What are the primary uses of wheat?
Food and animal feed
## Footnote
Wheat is a staple food for many cultures and is also an essential component of livestock diets.
38
What additional product can be made from wheat?
Spirits
## Footnote
Wheat is used in distillation processes to create alcoholic beverages.
39
What is a key characteristic of soft winter wheat?
Good source of starch
## Footnote
The high starch content makes soft winter wheat suitable for various food products and distillation.
40
What percentage of the dry weight of the wheat kernel is the endosperm?
65-70%
## Footnote
The endosperm is the main component of the grain that provides energy and nutrients.
41
What is the approximate percentage of the embryo in the wheat kernel?
3%
## Footnote
The embryo is the part of the seed that develops into a new plant.
42
What type of plant is rye?
A hardy plant that grows at high altitudes and can withstand very low temperatures
43
In which regions is rye mainly grown?
Europe, Asia, and North America
44
What family does rye belong to?
Poaceae
45
What is the genus of rye?
Secale
46
What is the species name for rye?
Secale cereale
47
What flavor is believed to be imparted to spirits when using rye in the distilling process?
A spicy flavour
48
What percentage of the dry weight of the rye kernel is made up of the endosperm?
Approximately 86%
49
Where does sorghum originate from?
South Egypt
50
How long ago did sorghum cultivation start?
Around 8000 years ago
51
What environmental conditions can sorghum tolerate?
Drought and extreme heat
52
Why is sorghum considered an ideal crop for dry, arid areas?
It can grow when other crops, like maize, cannot
53
List some uses of sorghum
* Food
* Animal feed
* Fuel
* Building material
54
What family does sorghum belong to?
Poaceae
55
What is the genus of sorghum?
Sorghum
56
What is the species name of sorghum?
Sorghum bicolor
57
Can sorghum be used to produce alcohol?
Yes
58
What is a reason for the increasing popularity of sorghum?
Its adaptability in difficult climates
59
In which countries is sorghum grown? Name at least three.
* USA
* Nigeria
* Sudan
## Footnote
USA, Nigeria, Sudan, Mexico, Ethiopia, India, Argentina, China, Niger and Australia as well as many other countries.
60
What is notable about the sorghum kernel's structure?
It does not have a husk
61
What percentage of the kernel weight does the endosperm make up?
Approximately 86%
62
What percentage of the kernel's dry weight is the embryo?
3.5%
63
What is the third largest commodity in the world?
Rice
64
What family does rice belong to?
Poaceae
65
What is the genus name for rice?
Oryza L.
66
What species of rice is known as Asian rice?
Oryza sativa
67
What species of rice is known as African rice?
Oryza glaberrima
68
How long has rice been a part of the human diet?
At least 4,000 years
69
What are the three main nutrients found in rice?
* Starch
* Protein
* Vitamins
70
What conditions can new varieties of rice tolerate?
* Drought
* Floods
* High salt levels
71
What is the most significant risk to rice crops?
Bacterial and fungal diseases
72
What alcoholic beverages can be produced from raw rice?
* Rice wine
* Sake
73
What is the most widely consumed staple food?
Rice
74
Is rice cultivation labor intensive?
Yes
75
What environmental condition is required for rice growth?
High rainfall
76
How can flooding benefit rice cultivation?
Reduces weed growth and deters vermin
77
Can rice grow without flooding?
Yes, but requires more effort to weed and control pests
78
What percentage of the dry weight of the rice kernel is the endosperm?
90-92%
79
What percentage of the dry weight of the rice kernel is the embryo?
3.3%
80
What protects the kernel of rice?
Seed coat (bran)
81
Fill in the blank: Rice has no _______ but has a seed coat that protects the kernel.
husk
82
Where did barley originate from?
Western Asia and northern parts of Africa
83
How long ago did barley cultivation start?
8,000 years ago
84
What is the current rank of barley among global crops?
Fourth largest crop
85
What is the family of barley?
Poaceae
86
What is the genus of barley?
Hordeum
87
What are the two species of barley?
* vulgare (six-row barley)
* distichon (two-row barley)
88
What is barley primarily grown for?
Animal feed
89
What type of barley is used in distilling?
Malting barley
90
How is malting barley different from feed barley?
lower in protein and higher in starch
91
What is the role of barley enzymes during the mashing process?
Breaking down starch to fermentable sugars
92
Does barley typically contain more or less starch than maize?
Less starch
93
What are malting barley varieties selected for?
* Agricultural potential (yield, disease resistance)
* Malting potential (fermentable extract, enzymes)
94
Which board approves barley varieties in the UK?
Agriculture and Horticulture Development Board (AHDB)
95
How many rows of kernels do two-row barleys have?
Two rows
96
How many rows of kernels do six-row barleys have?
Six rows
97
In two-row barley, which spikelet develops a kernel?
Only the middle spikelet
98
In six-row barley, how many spikelets develop a kernel?
All three spikelets
99
What are some traits of successful new malting barley varieties?
* Better yield (more tonnage per hectare)
* Shorter, more rigid straw
* Better disease resistance
* More uniform grain
* Better extract potential (more starch)
* Lower β-glucan and protein levels
100
What compound has been bred out of some barley varieties?
Glycosidic nitrile
101
What is ethyl carbamate (EC) identified as?
A trace compound in foods and alcoholic beverages
102
Why is ethyl carbamate (EC) a concern for distillers?
It is carcinogenic (cancer causing)
103
How is ethyl carbamate (EC) created in the distilling process?
From precursors produced by some malting barley varieties
104
What do distillers do to control levels of EC in their products?
Purchase malt made from barley varieties with low or null potential to produce precursors
105
What is glycosidic nitrile (GN)?
A precursor to ethyl carbamate produced by some malting barley varieties
106
What is the typical limit for glycosidic nitrile (GN) levels set by distillers?
Below 0.2 g/t
107
What is barley commonly used as?
Malted barley
108
What is the typical maximum moisture for storage of maize?
15%
109
What is the starch percentage (dry weight) for maize?
70-80
110
What are the other purchase specifications for maize?
Large, full kernels
111
What products are made using maize?
* Corn whisk(e)y and some grain whiskies
* Scotch whisky
* Grain neutral spirits (GNS)
112
What is the typical maximum moisture for storage of wheat?
15%
113
What is the starch percentage (dry weight) for wheat?
65-70
114
What are the other purchase specifications for wheat?
* Nitrogen < 2.0%
* Specific weight > 72 kg/hl
115
What products are made using wheat?
* Grain whiskies
* GNS
116
What is the typical maximum moisture for storage of rye?
15%
117
What is the starch percentage (dry weight) for rye?
Up to 86
118
What products are made using rye?
* Some US whiskies such as rye, bourbon and Tennessee types
* GNS
119
What is the typical maximum moisture for storage of sorghum?
14%
120
What is the starch percentage (dry weight) for sorghum?
Up to 86
121
What products are made using sorghum?
* Sorghum whisk(e)y
* Sorghum rum
* GNS
122
What is the typical maximum moisture for storage of rice?
14%
123
What is the starch percentage (dry weight) for rice?
90-92
124
What products are made using rice?
* Rice baijiu
* GNS
125
What is the typical maximum moisture for storage of barley?
12%
126
What is the starch percentage (dry weight) for barley?
57-88
127
What are the other purchase specifications for barley?
Nitrogen 1.5%
128
What products are made using barley?
* Unmalted barley used in some Irish whiskey
* Scotch whisky
* GNS
129
What is the Brix standard for liquid sugar from sugar cane and sugar beets?
67, minimum 62
130
What must sugar pass to avoid flocculation problems during production?
The haze test
131
What is the maximum humidity for storing sugar?
0.04 g/kg
132
What is the main use of sugar cane?
Most sugar cane is used for sugar production
133
What is a significant by-product of sugar production?
Molasses
134
What products are made using molasses?
* Rum
* Cachaça (Brazilian cane liquor)
* Vodka
* Gin
* Mekhong Whiskey
135
What is the first stage of the malting process?
Cereal delivery
136
What must be checked during cereal delivery?
* Moisture content
* Grain size
* No broken grains
* No signs of infestation
137
What is the second stage of the malting process?
Cereal storage
138
How should cereal be stored to prevent issues?
In a cool, dry environment
139
What is the purpose of the steeping process?
To soak cereal grains and start germination
140
What occurs during the germination stage?
Steeped grain is transferred to a vessel with a perforated floor for air control
141
How long does the germination process take?
Approximately four days
142
What is the purpose of kilning in the malting process?
To remove moisture, stop germination, and add flavor
143
What is the function of the perforated floor during germination?
To allow air to be blown through the bed of grain
144
What occurs during the steeping process of cereal grains?
Cereal grains are steeped in water to increase moisture content for germination
## Footnote
Steeping involves submerging grains in water, leading to germination.
145
What is the significance of the micropyle in the steeping process?
Most water enters the grain at the micropyle
## Footnote
The micropyle is a small opening in the grain where water absorption occurs.
146
What is respiration in the context of steeping grains?
Grains consume dissolved oxygen and starch from endosperm, producing energy, carbon dioxide, and heat
## Footnote
This process supports the growth of the grain during steeping.
147
How is heat managed during the steeping process?
Compressed air is blown into the steep water to mix the grain and prevent heat buildup
## Footnote
Mixing helps maintain consistent temperature and oxygen levels.
148
What is a typical duration for the first wet period in steeping?
4 to 8 hours
## Footnote
This duration allows the grains to absorb sufficient water.
149
What happens after the wet period in the steeping process?
The steep water is drained, initiating the first air rest
## Footnote
During the air rest, grains continue to germinate and require oxygen.
150
What is the role of fresh air during the air rest?
Fresh air supplies oxygen and removes carbon dioxide produced by respiring grains
## Footnote
This prevents suffocation of the grains.
151
How many wet periods and air rests are typically involved in steeping?
2-3 wet periods and 2-3 air rests
## Footnote
This cycle occurs over approximately 48 hours.
152
What is the change in moisture content of the grain during steeping?
Increases from about 12% to between 42% and 45%
## Footnote
At this moisture content, grains begin to grow.
153
What is the first sign of germination in cereal grains?
A small rootlet, known as a chit, appears at the embryo of the grain
## Footnote
The chit indicates the beginning of the germination process.
154
What are the typical shapes of steeping vessels?
Conical or flat-bottomed
155
What are the key features of steeping vessels?
* Filling and emptying facilities
* aeration
* carbon dioxide extraction
156
How is grain added to a steeping vessel?
Via the top of the steeping vessel
157
What is used to suppress dust during the transport of cereals?
Water sprays
158
How is grain distributed in a conical steeping vessel?
Spread over a cone
159
What mechanism is used to spread grain in a flat bottom tank?
Giracleur
## Footnote
Rotating arms with blades
160
Where is the water inlet typically located in a steeping vessel?
At the bottom of the steeping vessel
161
What controls the water level in a steeping vessel?
Sensors inside the steep tank and valves at the inlet
162
What happens to light materials like straw during the steeping process?
They float on the water and are removed through the overflow
163
What is the purpose of the perforated screens at the bottom of steeping vessels?
Allow water to be drained away, leaving the grain behind
164
How does the size of the perforated screen differ between conical and flat bottom vessels?
Conical vessels have small screens; flat bottom vessels have the entire floor perforated
165
What is the area under the perforated screen called?
Plenum
166
How does water usage compare between conical and flat bottom steeping vessels?
Flat bottom vessels use more water per tonne of malt
## Footnote
Plenum is quite large and must be filled with water before the water reaches the grain
167
What is done to replace the dissolved oxygen in steep water?
Compressed air is blown into the steep water
168
How is aeration achieved in a conical vessel?
Using an aeration ring or nozzles in the wall
169
How is aeration provided in a flat bottom vessel?
Using pipes under the vessel floor
170
What gas must be extracted during air rests to prevent suffocation of the grain?
Carbon dioxide
171
What mechanism is used to draw fresh air through the grain in steeping vessels?
Fans
172
Which type of steeping vessel has a more even airflow?
Flat bottom steep vessels
173
What is the duration of germination for steeped grain?
Between three and six days
## Footnote
This is done in a controlled environment to stimulate enzyme production.
174
What is the purpose of germination?
To stimulate the grain to produce important enzymes for sugar conversion
175
What is the process called that refers to the changes in grains during germination?
Modification
## Footnote
This process should be as complete and even as possible.
176
What are the two main environmental factors controlled during germination?
* Temperature of the grain bed
* Moisture content of the grain
177
What is the function of enzymes during germination?
Break down the protein matrix and cell wall components to access starch.
178
What makes up an endosperm cell?
* Cell walls made of β-glucan and pentosan
* Protein matrix embedded with starch granules
## Footnote
large and small starch granules
179
What hormone does the embryo produce during germination?
Gibberellic acid
180
What is the role of gibberellic acid?
This hormone stimulates enzyme production in the aleurone layer.
181
Where is α-amylase produced and what is its function?
Produced by the aleurone layer; breaks down starch into glucose chains of various sizes.
182
Where is β-amylase produced and what is its function?
Present in endosperm and activated during germination; breaks down long glucose chains into maltose.
183
What does limit dextrinase do during germination?
Breaks down branch points in glucose chains.
184
What are β-glucanases and pentosanases responsible for?
Breakdown of β-glucan and pentosan in endosperm cell walls.
185
What is the function of proteases in the germination process?
Breakdown of the protein matrix in endosperm cells.
186
What happens to the endosperm as barley grows during germination?
It becomes soft and can be rubbed into a paste with no hard lumps.
187
What is the term used for barley after it has been modified and is ready to transfer to the kiln?
Green malt
188
What physical change indicates that the endosperm is well modified?
It rubs into a paste with no hard lumps.
189
True or False: The starch granules in the endosperm are easily accessible without enzyme action.
False
190
What is a germination vessel?
A germination vessel is a container that holds a batch of germinating grain for between three and six days.
## Footnote
Typically circular or rectangular
191
What is a Saladin box?
A Saladin box is a type of rectangular germination vessel invented by Charles Saladin in the 1800s.
192
What are the common design features of germination vessels?
* Filling and emptying facilities
* A perforated floor
* Fans and air recirculation
* Turning machines
193
How is grain filled in a Saladin box?
A conveyor transports steeped grain along the length of the box and spreads it into multiple piles for the turning machine to evenly flatten across bed
194
How is grain filled in a circular germination vessel?
Steeped grain comes down a chute at the center and is directed to a horizontal screw that spreads it across the floor.
195
What is the typical depth of the grain bed?
Between 2 and 3 m
196
Why must the grain be distributed evenly?
To ensure even airflow through grain
197
How is grain emptied from a circular germination vessel?
The horizontal screw is reversed and pulls green malt to a chute in the middle of the vessel
198
How is grain emptied from a Saladin box?
The turning machine transports green malt to a conveyor in the floor or an elevator that lifts the green malt to a conveyor above the malt box
199
What is the purpose of the perforated floor in a germination vessel?
The perforated floor allows air to be forced through the grain, keeping it cool and preventing overheating.
200
What role do fans play during germination?
Fans blow saturated air through the germinating grain
201
How does the air get saturated and why?
Humidification sprays mist the air ensuring it is saturated with moisture to prevent moisture loss from the grain.
202
How is temperature controlled during germination?
Warm air from above the grain bed can be recirculated back into the air being applied under the grain bed using recirculation louvers.
203
How does a turning machine operate?
Multiple vertical helical screws rotate to pull germinating grain from bottom to top of the bed
204
What is the function of turning machines in germination vessels?
Turning machines break up tangled rootlets in the grain, ensuring proper airflow and easy emptying of the vessel.
205
How often do turning machines operate?
Turning machines typically move through the batch every 8-12 hours.
206
What is an alternative type of germination vessel?
A rotating drum can be used to gently turn the green malt, preventing rootlet matting while providing airflow and temperature regulation.
207
What is the primary aim of kilning?
* To reduce the moisture content of the green malt so it can be safely stored
* Preserve the enzymes the grain has produced during steeping and germination
* Add flavour to the malted cereal
* Complete the kilning process in time for the next batch to be kilned
208
What is the air-on temperature in the kilning process?
The temperature of the air being forced through the malt bed
209
What is the purpose of air-on air?
To dry the green malt and cool the air
210
What does the air-off temperature refer to?
The temperature of the air coming off the bed of green malt
211
What is the air-off relative humidity?
The humidity of the air coming off the malt bed
## Footnote
It indicates the moisture removed from the green malt.
212
What does the air-off relative humidity indicate?
the moisture removed from the green malt
213
How many phases are there in the kilning process and what are they?
Four phases
* Free drying
* Forced drying
* Curing
* Cooling
214
What is the moisture content of green malt at the start of kilning?
Typically between 43 and 45%
215
What does the high moisture content tell us about the green malt enzymes?
They can be damaged by excessive heat
216
Why is it called the free drying phase?
green malt freely releases moisture from its surface into the air
217
What temperature range is used during the free drying phase and why?
55-65°C
Prevents enzyme damage
218
How long does the free drying phase last?
6-8 hours
219
What happens at the break point during the free drying phase?
The air-off temperature begins to increase and air-off relative humidity decreases
## Footnote
This indicates the end of the free drying phase.
220
Why does the break point occur?
all the free surface moisture has been removed from the green malt
221
What is the temperature range increased to during the forced drying phase?
65-75°C
222
How long does the forced drying phase typically last?
8-10 hours
223
Why is the temperature increased during the forced drying phase?
to force the remaining moisture out of the inside of the grain kernel
224
What is the purpose of the curing phase?
To determine the final moisture
225
What is the typical final moisture range of the malt?
4-6%
226
What temperature range is applied during the curing phase?
75-85°C
227
How long does the curing phase typically last?
30 min to 1 hour
228
What indicates the end of the curing phase?
When the air-off temperature reaches a set point
229
What is the purpose of the cooling phase in kilning?
To cool the malt so it can be safely stored
230
How is the malt cooled during the cooling phase?
Ambient air is blown through the malt bed
231
When does the cooling phase finish?
When the air-off temperature is less than 30°C
232
What is the typical design of kilning vessels?
Kilning vessels are typically circular in design although sometimes they are rectangular.
233
What features do kilning vessels share with germination vessels?
* Filling and emptying facilities
* Perforated floor
234
Why do kilning vessels not have turning machines?
Because the rootlets produced by grain during germination dry out and fall off during the kilning process.
235
How deep is the grain bed in a typical kiln?
Approximately 1 m deep.
236
What is the primary method used to heat the air in kilns?
All kilns are heated by burning some sort of fuel, typically natural gas or oil.
237
How does a directly heated kiln function?
The air is heated directly by the combustion gasses of the fuel.
238
What is NDMA and why is it significant in malting?
N-Nitrosodimethylamine (NDMA) is a potential carcinogen produced from reactions between nitrous oxides and nitrogen-containing compounds in malt.
239
What NDMA levels are expected in malt?
NDMA levels below 1.0 µg/kg are expected.
240
Describe how an indirectly heated kiln operates.
A fuel is burned but not used to heat the air directly
241
What is the role of fans during kilning?
Air is blown through the green malt
242
What happens to the air at the end of the kilning process?
The air coming off the grain bed is hot and relatively dry.
243
What is the purpose of recirculation louvers during kilning?
To control the proportion of air that is recirculated during kilning.
244
Why are heat exchangers used in kilning?
To capture valuable heat from the exhaust air and heat the incoming ambient air.
245
What materials are typically used to construct heat exchangers?
Heat exchangers are typically made from glass or stainless steel.
246
What is a germinating and kilning vessel (GKV)?
A vessel where the germination and kilning processes are combined, eliminating the need to move grain between vessels.
247
What were the first large scale malting houses known as?
Floor maltings.
248
How was grain treated in early floor maltings?
Grain was received into the top and dropped into deep cisterns for steeping, then piled onto a stone floor for germination.
249
What thickness of grain layers was required for sufficient temperature control during germination?
Thin layers of 8-15 cm.
250
How was room temperature controlled in early malting houses?
By opening vents in the walls and manually turning grain
251
What limitation did early kilning processes face?
Limited air flow due to a lack of fans to blow hot air.
252
What architectural feature is associated with the distinctive outline of malt whisky distilleries in Scotland?
Pagoda roofs.
253
Are there still floor maltings in use today?
Yes, there are still a few, such as the one at Highland Park Distillery in Orkney.
254
What is the trend in malting production today?
Most of the malt used today is made in large scale commercial malting plants.
255
What is peat?
Decayed plant material or organic matter that forms over thousands of years.
256
What is the key ingredient for producing peated malt?
The smoke produced by burning peat.
257
How is peat burned to produce smoke?
In a separate unit (firebox) under controlled conditions to produce smoke and minimize flames.
258
What are the compounds known as that provide flavour and aroma in peated malt?
Phenols.
259
What is the required moisture content of peat for burning?
50-60%.
260
Why is controlling peat moisture level essential?
Smoke is required when burning peat, not flames.
261
What contributes to the unique characteristics of a peat smell?
High levels of organic material in peat.
262
List some flavour compounds found in peat.
* Phenol
* Cresol
* Eugenol
* Guaiacol
263
What type of malted wheat is typically used in distilling?
Pale and lightly kilned malted wheat
## Footnote
Malted wheat used in food is typically darker and imparts a sweet flavor.
264
What influences the selection of wheat for malting?
The nitrogen (protein) content
## Footnote
Wheat nitrogen is typically less than 1.60%.
265
Which type of wheat is good for malt used in alcohol production?
Soft wheat
266
What is the typical moisture level for steeping wheat?
42%
267
At what temperature is wheat germinated?
Typically lower than 16˚C
268
How long is wheat usually in the germination vessel before kilning?
Up to five days
269
What is a notable characteristic of wheat malts in terms of fermentation?
High levels of free amino nitrogen (FAN)
270
What is a key enzyme characteristic of rye malts?
High levels of α- and β-amylase enzymes
271
Why must rye be treated similarly to wheat during processing?
Rye has no husk
272
How does rye behave during the steeping process?
Rye rapidly takes up water
273
What is the germination duration for sorghum malt?
Four to six days
274
What happens to α- and β-amylase enzyme levels during the germination of sorghum malt?
They increase
275
What is the typical moisture content of malt distilling malts?
Around 4.5%
## Footnote
Moisture content above 7.0% can complicate milling in conventional roller mills.
276
What moisture content range is typical for grain distilling malts?
Between 5% and 6%
## Footnote
This higher moisture is manageable for grain distilleries using hammer mills.
277
Why must malt be dried?
* To stabilize it for long-term storage
* To allow it to be milled in conventional roller mills
278
What is the extract of distilling malt?
The measure of the total material available from the malt for the yeast during fermentation.
279
What does a higher extract in malt indicate?
A higher specific gravity of the wort produced.
280
What is the main concern for grain distillers regarding extract levels?
They are primarily focused on providing enzymes and soluble nitrogen/FAN.
281
What do friability and homogeneity indicate about malt?
How easily the malt will mill and how evenly it has been modified.
282
What friability percentage indicates malt is suitable for malt whisk(e)y production?
Greater than 86%
283
What is the typical friability specification for grain distilling malt?
Greater than 80%
284
What does a fermentability test measure?
The percentage of extract that can be fermented by yeast.
285
What is the constant factor used to calculate alcohol yield in litres of alcohol per tonne (LA/t)?
6.06
286
What are the two main enzymes involved in mashing?
* α-amylase
* β-amylase
287
What is diastatic power (DP) a measure of?
The malt's ability to degrade starch.
288
What enzyme potential is expected for malt distilleries?
Greater than 75 °IoB (240 °WK EBC) DP
289
What enzyme potential is expected for grain distilleries?
* 165-200 °IoB (500-600 °WK EBC) DP
* DU greater than 65°IoB/EBC
290
What do soluble nitrogen and FAN provide during fermentation?
Nutritional sources for yeast.
291
Why are soluble nitrogen and FAN particularly important for grain distillers?
The raw cereal contributes little soluble nitrogen and FAN.
292
What does the phenol level in malt indicate?
The level of smoky aromas in the finished spirit.
293
What is required for non-peated whisk(e)y regarding phenol levels?
The malt must be free of phenol.
