Mod 3 Raw Materials Flashcards
All water used during the production process in the Scotch whisky industry is
derived from
Rain or snow
The basic requirements of
water supply are that it is
adequate and available
water sources
- springs
- burns/rivers
- lochs
- wells
- boreholes
- mains
Water is used in several key phases of the
production process (3)
- steeping & mashing - ph microbiological purity
- cooling - volume temp
- dilution - ph,hardness, volume, temp, microbiological content.
why is it good to know the mineral content and ph balance of water when steeping and mashing
steeping and mashing are
basically biochemical processes, they can be
affected by the mineral and ion content - and by
the pH - of the water.
Why know hardness level
The mashing water used can influence the
fermentation, depending upon the hardness levels
and ions present.
soft water
heavier new make
Harder water
cleaner/sweeter new make
spirit
Cool Water
cool water is required for the
condensers, therefore the quality parameters here
are simply volume and temperature
Dilution
For cask filling. Water must pure
in terms of lack of solids and microbiological
content. Quality parameters that can be measured
therefore are pH, hardness, volume used,
temperature and microbiological content.
Once sourced, that water is used at four
key parts of the production process
steeping, mashing, cooling & dilution.
Main raw material in the production of single malt
Barley
Malting barley moves through 3 key stages in the pre production process
- growth & harvesting,
- variety development
- testing
Growth and harvesting
- malting barleygrown predominately on east side of uk
- lower rainfall than the west
3 . preferable soil - Harvesting takes place in the second half of July
and August in Southern England and East Anglia
and can start four to six weeks later in Scotland
Variety development
Each barley variety has different characteristics
and morphological features
some features are
1. grain shape
2. rachilla in ventral crease
3. Nerve pigment and colouring
Shape of grain
Is it bold, thin, or flat
Rachilla
a structure in the ventral crease, can be short or long.
Can have hairs that can be short and wolly or long and straight
what maltsters like in malting barley
Cost effective
* Bold grain
* Appropriate nitrogen level
* Good germinative ability
* Varietal purity
* Reliable supply
* Suitable storage
Best malting barley
homogenous bulk, with bold and even grains.
Grains of the same size will hydrate and process at
the same rate, leading to more homogenous malt.
Homogeneous Malt
Homogeneous simply means of the
same kind or alike. In malting, the
term is often used when describing a
sample of barley at intake.
Numerous samples, for example,
are taken from across the load and
mixed thoroughly to ensure, overall,
the sample is homogenous. Physical
features such as rachilla hairs and
spicules are assessed.
Agriculture and
Horticulture Development Board (AHDB).
Testing and breeding system in the UK
produces a recommended lists of barley varieties
and recommends those to use in the various
industries.
Agriculture and
Horticulture Development Board (AHDB).
Testing is done
prior to maltsters buying barley
5 test on barley
- Nitrogen
- Moisture
- Screenings
- Germination
- Varietal purity
Reference method for nitrogen
Dumas method
Near Infrared (NIR) equipment
equipment that most analysis is carried out on
barleyis dried because
a) off the field it is too wet for storage (in England the
moisture level is usually between 14-16% whereas in Scotland it can be up to
20%),
b) infestation can occur (insects cannot breed in barley if it is less than
15°C and less than 12% moisture
c) dry barley can be stored safely for
longer (germination potential can be inhibited if stored at higher moistures
and temperatures).
Insects cannot breed in what temps
(insects cannot breed in barley if it is less than
15°C and less than 12% moisture
recognized industry levels for barley temps and moisture during storage are
are less than 12% moisture
& 15°C.
how is barley dried
tower drier method
The drying is controlled by the rate of barley
flowing through the drier and the temperature of
the air being used. The wetter the barley, the lower
the air on temperature is required to be, as wet
barley can be damaged by heat
how is barely stored
Silos
ventilation systems normally suck air rather
than blow air. Flat store or ‘big shed’ have a
higher capital cost and can result in waste. The
air is blown through the bulk via permanent or
temporary air ducts.
barely is stored
in a silo or flat store
steeping
raising the moisture level to such an extent that
germination is initiated.
barely is dried prior to storage because
because, once off the field, it is
usually too wet to store. Drying barley also helps to reduce what is called dormancy in the grain
Dormancy
is the natural tendency
to inhibit germination, and can vary
depending upon variety, growing
conditions and harvesting conditions.
self-emptying cylindroconical vessel
very water efficient compared to false bottom
flat steeps, used for steeping
level of hydration in grain dependent on
Water temperature
* Grain size
* Variety
* Viability
Water temperature
Higher water temperature
results in more rapid water
uptake and may be required if
the grain is less mature
Grain size
Larger grains require more
time under water to reach
the same moisture level as
smaller grains.
Viability
The maturity (or viability)
of grain also affects water
uptake, with the barley
taking in water more
quickly as it matures.
Variety
Different varieties may take
in water at different rates,
so steeping cycles would
be altered
Optic typically
takes longer to reach the
same moisture level than
Concerto.
Multiple Steeping
The multiple steeping cycle normally takes place
over a 48-hour cycle and consists of two or three
‘wet’ periods, with ‘air rests’ in between.
What is multiple steeping
The multiple steeping cycle normally takes place
over a 48-hour cycle and consists of two or three
‘wet’ periods, with ‘air rests’ in between.
Target moisture at the end of steeping
the mid-40s but the actual figure is dependent
upon the type of malt being made.
higher steep out or cast moisture
result
in increased respiration and therefore increased
malting loss. It will also result in increased enzyme
activity and soluble nitrogen content.
Cast moisture
is the moisture level in the
grain as it is moved from the steeping
stage to the germination stage.
Cast moisture
- the more water, the
more active the grain, until you get to the
stage where it will drown. - The more active the grain, the quicker
the breakdown processes inside the
grain;
Hydrolysis
the technical term for the
breakdown of starch into sugars.
Germination physical changes
After water intake, the grain has
swelled and a small white chit (root cover) can be
seen.
Chemical Changes
Enzymes, stimulated by
the release of hormones, are released into the
endosperm degrading the cell walls and protein
matrix, thereby making the starch supply available
for hydrolysis during the mashing process.
Germination
produces the enzymes required for
the hydrolysis process. And distillers want the
starch and the enzymes
Structures in barley grain related to germination
- Micropyle
- Embryo
- Endosperm
- Husk
Germination
Embryo
the living part of the grain,
sometimes called the germ; it is the ‘baby’ plant.
Micropyle
the structure at the embryo end
of the corn that allows water to flow into the grain
(Basically, it is a hole that allows for water to
enter.)
Husk
the ‘skin’ that surrounds and protects
the barley.
Endosperm
the food reserve for the embryo.
It is a hard structure consisting of starch molecules
(long chains of sugar molecules) embedded within
a protein matrix all surrounded by cell walls.
Endosperm during germination
altered due
to the action of enzymes.
what does the embryo release at the start of germination
a
hormone called Gibberellic Acid, known as GA3.
MOdification Front
This initiates the aleurone layer to release
the enzymes required to break down the cell
walls, protein matrix and starch granules.
Modification front breakdown occurs
from the embryo end to the
distal end of the grain.
Malting Loss
Germination is complete once the endosperm has
been made friable. That is, it can be rubbed out;
meaning the cell walls and protein matrix have
been broken down.
starch is also broken down and used
for root and shoot growth, this usage is
Malting Loss
Controlled Germination
Keeps malting loss at a minimum
more malting loss that occurs, the less starch available for distillers to work with
Enzyme release timing
- Cell walls break down first
- second, protein matrix
- third, the starch
Physical changes during germination
- the grain has swelled and a
small white chit (root cover) can be seen. If the
husk is peeled away, the endosperm is still hard
but getting rubbery. - Rootlets appear - endosperm can be rubbed out once rootlets are at their strongest
Rootlets
Endosperm
the cell walls, protein matrix
and starch granules
Germination Vessels Features
- Mechanism to load and empty the vessel
- False bottom to allow air flow
- Fan for blowing humid air through the bed
- Mechanism to turn the grain
What has improved the control of germination
Drum maltings
Cool air can be blown through the
perforated deck into the grain bed thus removing
heat and carbon dioxide. The bed is turned
automatically by rotating the drum.
Second main stage process of malting
Germination
What is germination
the modification of the
endosperm and uses enzymes.
What is measured during germination
- growth
- temperature
- moisture
Kilning
heat the germinated
barley to dry it and, crucially, to stop germination.
The moisture in the grain is reduced to 4-5% prior
to further use in the distillery.
at what stage can flavor and color be added
Kilning
What does kilning do
It reduces some
undesirable flavours in the malt and stabilises the
enzymes, so that they can be utilised later during
mashing.
What percentage does kilning reduce the moisture in the grain to
4- 5%
two important parameters of kilning
- air on - temp entering the grain bed
- air off - temp leaving the grain bed
Why are there lower air temperatures used at the
start?
To protect the enzyme systems in the green
malt. As the grain is dried, the air on temperature
can be increased, as the enzyme systems are
stabilised.
Free drying
also known as pre break
air off increases in temp when?
as the kiln time progresses and as
the grain dries, the air off has less moisture and
therefore increases in temperature. This stage is
known as forced drying (or post-break).
Parameters monitored during kilning
- Air
Air on and air off temperatures. - Humidity
Humidity for air off (although this is not very
common). - Moisture
The moisture of the malt
These parameters are determined at the end of
the kilning process.
is endosperm softer during kilning?
Yes
What develops flavour and color
maillard reactions and NDMA formation
NDMA
formation
formed when nitrous oxides react with
nitrogen compounds in the presence of heat)
could have occurred unless care is taken.
Maillard reactions
formed from amino acids
and sugars in the presence of heat
chemical
reactions that take place in heat,
producing flavour and colour
compounds. They take place in the kiln
when temperatures reach above 160°C.
Amino acids (from the protein matrix
breakdown) react with the sugars (from
the starch breakdown) to produce colour
and flavour.
What is NDMA
a carcinogenic compound
that can be formed in kilning under
certain circumstances. NDMA
formation is a bad thing in malt as
this compound has been found to
be a carcinogen and therefore has
legislative limits for spirit in some
countries. NDMA can travel through
the process into the spirit, so the
malt and the new make spirit are
routinely analysed for NDMA as a
due diligence test. Modern practices
however reduce the formation of
this compound in the malt.
What is Peat
is an additive and is used to add flavour to
the malt during the kilning process. It is partially
decomposed plant material, produced in a wet
environment in the absence of oxygen. Peat can
be dug up and dried, thus becoming a fuel that
can be burned.
How is peat described (2 ways)
- Medicinal (TCP, germoline, hospitals)
- Smoky (smoked meat, burnt wood, bonfire)
What differentiates peat
Different areas in Scotland produce peat with
different active compounds, dependent upon
plant species and environmental conditions
How much original phenolic compound ends up in the new make
about 1/3rd. Can be altered in the still run.
it is all about the spirit to feints cut
in the spirit still (
When are phenols collected
in the later part of the heart or spirit cut
Phenols
- heavier more medicinal phenols come off later in the run vs lighter smoke and bonfire earlier
- later you cut from spirit to feints, the heavier the new make
- Lagavulin
and Caol Ila use the same malt so have the same
phenol range entering the stills, but Caol Ila cuts
off spirit earlier so has less medicinal phenols
in their spirit than Lagavulin
the same malt
produces an entirely different spirit due to the
spirit-to-feints cut point.
True
The longer the spirit run, the more phenols in the
spirit; this also results in a lower alcohol strength
in the final spirit collected.
True
too long of a spirit run can result in feinty characteristics
True
How long storage for kilned malt
3 weeks
why 3 weeks
allows for homogenization of the
analysis and allows the malt to ‘settle’.
fiery Stills
A fiery still is when it is very hard to
control the level of frothing inside the
still at the start of distillation, and can
sometimes lead to carryover where froth
and solids go through the condenser into
the safe. This will cause quality issues in
the spirit. You normally get fiery stills if
the malt processed has not been rested
for at least three weeks after kilning.
Deculmed Malt
Rootlets removed, done prior to dispatch
Third main stage of malting process
Kilning
Important parameters of kilning
air on and air off
A flavor and coloring added during kilning
peating
what adds medicinal and smoky flavours
Peat
Steeps today
cylindroconical vessels that load
via gravity into a germination
vessel. They use compressed
air for rousing
Drum maltings greatly improved the control of
germination
True
Kilning systems have improved cost effectiveness
True
Steeps use compressed air to rouse the
grain and fans to remove CO2 and heat.
True
Germination vessels all have false
bottoms for air flow and a means to mix
up the grain
True
Kilns are now designed to improve
efficiency such as the use of waste heat
True
what system makes use of a small foot print
tower malting system
what happens before milling
- malt passes through a destoner
- a magnet is used to remove ferrous material
MIlling process
- The first set of fluted rollers are used to open up
the grain, breaking off the husk. - Subsequent sets of rollers grind up the
endosperm. - Beaters in between the sets of rollers remove
husk, fine grit and flour; meaning only the larger
grits pass through the bottom rollers.
What is Grist
malt is ground into grist
Grist is made up of approximately
10% flour, 70% grits and 20% husk.
Grist analysis
- needed for spirit yield
- impacts sucess of the mashing operation
at a large efficient distillery 1 tonne malt
produces 415 to 420 litres of spirit
smaller distilleries produce from 1 tonne malt
400 litres
Yeast
a single-celled organism which feeds on sugar, producing alcohol,
carbon dioxide and heat in return.
Yeast used for distilling
Saccharomyces cerevisiae
It typically has a 10 micron cell diameter
and 1,000,000,000 cells per gram.
Yeast cell division
yeast propagates by budding
daughter cell to mother cell
Anaerobic respiration
In the absence of oxygen, yeast metabolises sugar
to give ethanol.
What can affect yeast
- infection
- alcohol
- sugar
yeast strain can change the flavor profile in the wash
true
what is pitching rate
the amount of
yeast used can also affect the congener profile by
altering the rate of fermentation
why is wort clarity iimportant in terms of spirit character
a cloudy wort has the potential to give rise to a
nutty spirit, a clear wort more likely to give a fruity
or sweet spirit
Yeast
one of the three raw materials
permitted for single malt Scotch whisky
Yeast is a single cell organism which can
metabolise sugar into ethanol
True
Mashing
he process of adding hot water to the grist
Mashing process is filtration
- the solids form a filter bed,
- the liquid is filtered through this bed
- drains out the bottom of the mashtun.
Purpose of mashing
breakdown the
starch in the grain and turn it into fermentable
sugars.
wort
a sugary liquid, drained into the washback
where fermentation occurs.
spout temperature is vital
it is at this point
where most of the enzymatic activity occurs.
Optimal mashtun temperature
63.5C this temp balances the gelatinizatio of the starch with the enzyme activity
Gelatinisation
simply means getting the
starch to become soluble in water. When
the starch swells and is hydrated, it can
be dissolved in water which allows the
enzymes access to do their work.
Would happen faster at +63.5 but would be denatured
Enzymes at the spout
- α-amylase
- β-amylase
α-amylase
reacts at random along the chain of the
starch molecules breaking the α-(1,4) bonds, thus
chopping up the starch. This activity reduces once
you get above 67°C.
β-amylase
more selective,
releasing maltose molecules from the nonreducing
end of the starch. This enzyme is far less
stable with heat, with all activity ceasing after a
time at or above 65°C.
secondary conversion
remove the wort and cool it quickly so
that the enzyme activity can be continued in the
washback;
This is vital
limit dextrinase
Another enzyme
breaks
down the branches in the starch molecules, acting
upon α-(1,6) bonds, producing more straight chain
dextrins.
where does limit dextrinase happen
does happen in the mashtun but
more predominantly in the washback as part of
secondary conversion.
normal operation in distilleries now
means that all further waters are added in one
continual sparge
True
Subsequent ‘waters’ are added at a higher
temperature to allow for full gelatinisation of the
starch. Higher temperatures can only be used as
adequate levels of enzymes have been removed
into the washback with the cooled wort, thus
allowing for the breakdown of the gelatinised
starch in the next stage of the process.
True
Why is wort cooled between16 -20C?
- To preserve the enzymes to ensure
secondary conversion - To protect the yeast that will be added
to the washback
4 types of Mashtuns from older to newer
- traditional
- semi lauter
- full lauter
- filter
What do mashtuns have in common 1
- Mixing grist -this must be done in such a way as
to fully hydrate the grist thus leading to maximum
starch gelatinisation and commencing the
hydrolysis of the starch molecule
Mashtun common 2
- Additional water -
Additional water must be able to be added into
the tun and the resultant liquid (wort) must be
able to be removed or pumped. The wort must be
cooled after draining through the slotted floor and
false bottom in the tun.
Mashtun commonalities 3
- Stirring or slicing -
Each type also needs a mechanism for stirring
or slicing through the bed, to allow for increased
drainage.
mashtun commonalities 4
- Draff removal
Each type of mashtun must have a system
designed to remove the left over draff. can be simple but now usually automated
in-place cleaning
New progression in mashtun design
an automated system
cleans in the tun and under the floor, normally
with hot caustic; thus removing the need for
operator entry.
other developments in mashtun technology
- Temperature probes are now much more
accurate and reliable, thus leading to
improved efficiency and constancy. - Automation, along with computer control,
has improved levels of consistency and
further reduced operator requirements. - Development in pumping control has
removed the requirement for an underback
and many sites now pump directly to
the washbacks.
traditional mashtuns are associate dwith
- distilleries with visitor centers, ie springbank
- a cloudy wort due to the continual break up
of the bed by the rakes or paddle
semi-lauter
have to stop
pumping while extra water is added.
referring to mashtun operation - the arms and knives are at a fixed
height.
full lauter
water can be added as
wort is removed,
referring to arms in mashtun operation - the arms and knives can be raised
and lowered.
What is a mashtun made out of
cast iron or stainless steel
The bottom is effectively a sieve which
allows the sugary liquid – wort – to drain
through to the underback (if there is
one) and then onto the washback where
fermentation occurs
True
