Whisky production Flashcards
What are the three main sources of flavour in whisky production
-The raw materials (Water, malted barley and yeast)
-The production process (Mashing, fermenting and distilling)
-Maturation
What kind of difference to flavour is water said to make
Little to none in comparison to the other factors if it is pure water
Where does water have the most impact in whisky production
During fermentation as its main influence is on the yield of the whisky
How may water impact the flavour of a whisky and during what process
Water can increase the yield of the whisky however the increased yield can make the resulting whisky less flavoursome
Water is preferable with what kind of pH
A high pH as soft water is a better solvent than hard water
What are the benefits of soft water during mashing
It is a better solvent and extracts more from the malt during mashing
Why might one be so inclined to believe that peaty water is better than just soft water
Peaty water contains carbon dioxide and acid producing bacteria from the peat which means its capacity to dissolve solubles in enhanced
what is the most important commonly regarded factor that is controlled by water
Purity as it is imperative that it be pure of organic and mineral impurity
How many scotch distilleries use distilled water and what are some of their methods of treating water
None, their means of treating water is to use UV light to kill any harmful bacteria such as ecoli
what two large factors influence the placement of a distillery regarding water
Its volume and temperature
how does water temperature affect the spirit in the cooling tubes after being distilled
Warmer water in the worm tubs mean that the vapours take longer to condense and liquify so there’s more contact with the copper so the spirit is lighter and purer
If a distiller wants a heavier more traditional spirit then why might the water be cooler in the worm tubs when cooling the copper coils
Colder water means that the vapours condense quicker and liquify faster so there’s less contact with the copper producing a heavier more ‘traditional’ spirit
In what months are most distilleries generally the most productive and which season do most distilleries time their ‘silent season’ for
Traditionally distilling is a winter activity and the silent seasons are usually when water levels are lower during July and August (the summer months)
How is barley graded
On a scale of 1 to 9 with only the top three grades being suitable for malting
Of barley grades 1 to 9 only the top three grades are suitable for malting and whisky producing, what percentage of barley is this?
around the top 20% of barley
how is quality defined in barley by Maltsters
-High starch content
-Low protein content
-Low nitrogen content
-High likely hood of germination
-easy to process
-well ripened
Why is it better suited for barley to have a high starch content
The starch is what is converted into sugar and then alcohol so higher starch yeilds higher alcohol
Why is it better suited for barley to have low protein content for whisky
higher protein would mean less starch so less protein means that there is more starch
Why is low nitrogen suited for barley used for whisky
high nitrogen is indicative of high protein which is not suited to barley as it means there is less starch
Why is it difficult for farmers to keep nitrogen low in their barley
nitrogen is the key ingredient of many fertilisers which are used to achieve a high yield, so farmers are forced to not over use fertilisers otherwise the barley becomes unsuitable for whisky
why is the high likely hood of germination an important factor of barley grown for whisky
Germination is a pre-requites for malting so it is essential that the barley is able to germinate
Why is it important that the barley is easy to process for whisky
It needs to be processed quite heavily in the mill and mash and not become glue-like as some varieties can
why is it important for whisky barley to be well-ripened, plump and dry
farmers are often told to leave the crop until its absolutely ripe and cannot wait any longer then leave it for 3 days because barley with moisture greater than 16 will go mouldy in storage (although this is now less of an issue with artificial drying)
why do distillers buy malt from scotland, the UK and abroad
To spread the risk of bad local harvests
what is the rough distribution of produced barley used for whisky
75% is from Scotland, 15% is from England and 10% is from abroad (France and Denmark)
what five regions is the UK divided into in terms of barley grown
Northwest (including northern Ireland and North Wales), Northeast, Central, Southwest and Southeast
until the 1950s which barley varieties dominated the market
Spatt archer and Plumage archer
What were some of the hybrids produced from Spatt and Plumage archer barley
Proctor, Pioneer, Maris otter and Golden promise
Which was the barley Maris Otter a hybrid of
Proctor and Pioneer
Which of the barley hybrids was the most important of the malting barleys in the 1970s
Maris otter
which barley variety introduced in 1966 was especially popular and why
-Golden promise
-It thrived on Upland farms
-gave higher yields
-it germinated quickly and evenly
How was the barley variety golden promise superseded
New varieties yielded increased alcohol levels and were less vulnerable to mildew and disease
In the 1980s what varieties of barley were introduced and what were they replace with by the 1990s
Halycon, Pipkin and Puffin were all introduced but later replaced by Optic and Chariot
What is currently the most popular variety of Barley
Laureate
Why has there been a slight increase in demand for golden promise [the barley variety] in recent years
its been in increased demand from smaller distilleries on account of the quality of the spirit even at the expense of yield.
what kind of differences are offered by the different varieties of Barley used in whisky production
little as any potential flavour differences are likely worked over due to intense processing and alcohol. However spirits made with Golden promise can be more oily and richer.
what is the modern day potential fear surrounding varieties of Barley
There is concern that new varieties sacrifice flavour to alcohol yield and resistance to diseases as well as that they change to quickly as new hybrids are developed.
What is yeast and how many cells of it are in a gram
It is a fungi micro-organism, one gram of which has around 10 million cells
What are the main products of yeast breaking down sugars
Carbon dioxide and alcohol
what is the typical pitch in terms of yeast percentage to the volume of malt mashed
Around 2.2%
Using the normal amount of yeast, how much yeast would your typical mash of eight tonnes require
175kg
How long does it take for a visual reaction between the yeast and the mash take to occur
a couple of hours
how long could fermentation go on for and what solution is produced and what is it called
It can go on for over 50 hours and it produces a saccharine malty solution called wash
What is Wash produced as during fermentation
Wash is a saccharine malty solution which foams a lot
how is the foam broken inside the washback to prevent it overflowing or building up pressure and how has this changed in the past
In the past were the yeast was less predictable people were employed to fight back the foam with heather flails or brooms. Now however mechanical switchers are used to break the foam
On occasion what a be added to help break the foam
Unperfumed liquid soap
what sort of yeast do distillers use today
cultured yeast that is grown from a single cell and it is either liquid, dried or most commonly solid
how does the yeast contribute to flavour
The yeast produces alcohol and congeners which include a range of esters, aldehydes, acids and other higher alcohols that all contribute to flavour
What do congeners from yeast contribute to the flavour
They produce a range of esters, aldehydes, acids and other higher alcohols
what two parts make up the barley (which is a seed)
An embryo (The part that grows into a new plant) and the endosperm (which is the store of starch that feeds the young plant)
during germination what enzymes does the barley predominantly produce and what’s its purpose
-Cytase which breaks down the cell wall and enables the starch accessibility for growth
-Amylase (also called diastase) which converts starch into a soluble form dextrin
What is dextrin (starches soluble form) converted into by amylase during mashing
Maltose a soluble sugar
what is malting in simple terms
It is effectively controlled germination
what do maltsters try to achieve during the germination process i.e what stage do they try to get to and how do they end the germination at that stage
They try to get it to a stage were the cell walls have been broken down but the starch has not yet been used by the growing plant. They stop germination at this stage by drying the ‘green malt’ in a kiln
What is green malt and why is it put in a kiln
Green malt is malt that has been going through germination and it is put in a kiln to dry it and stop germination at the desired stage
What moisture does dry barley have
12%
what moisture level does barley need to have in order for enzymes to be activated
46%
After the barley is cleaned how is its moisture level raised from around 12% to 46% after kilning
It is immersed in fresh water 3 times and this lasts for two to three days
How is the time that barley needs to remain immersed under water during steeping affected and changed
-Nitrogen levels
-temperature of the water
-ambient temperature
-Size of the grains
-The grains capacity for absorption
How is clumping during steeping avoided
The barley is constantly aerated whilst underwater which ensures equal uptake of water as well
what can a maltster do if they oversteep of understeep the grain
-If they oversteep it and it absorbs to much water it can be dried out by a tumble drying process
-if he under steeps it he can spray it however this can lead to uneven water uptake
how is regular germinating carried out i.e in the traditional sense
The barley is spread out across a concrete floor (Floor malting) to a depth of around 30cm
If floor malting is carried out why does it need to be turned with wooden shovels
the grains of barley sprout little rootlets which generate heat especially close to the floor so they must be turned to keep temperatures even and prevent the roots tangling
What does ‘turning the piece’ refer to in terms germinating barley
this is the process of turning barley to ensure even temperatures and prevent the roots from tangling
How long does floor malting usually go on for
it is usually about a week or less in hot weather
at what rate during germination does the barley loose moisture
The moisture is lost at around 0.5% per day
what eventually happens to the rootlets during germination and how do maltsters gauge if this has taken place and whether germination has gone on for the right length of time
The rootlets wither and die and maltsters will taste the grain to test its sweetness as well as rub it to access its texture. If it is chalky and smooth it is ready, if it lumps then it is not.
What does the term ‘modification’ refer to in terms of germination
Modification refers to the rootling’s of the barley withering and dying and the green malt becoming mealy which is tested by its sweetness and texture
how can having your own maltings be beneficial and what are the downsides of this
it allows for greater control of the flavours sought, its more natural and it doesn’t force germination. However it is slower and requires suitable space for doing so.
Which distilleries produce 10-20% of their malt requirement with their own floor maltings and which distilleries meet 100% of their malt requirement via their own floor maltings
Bowmore, Laphroaig, Balvenie and highland park all produce 10-20% of their own barley and floor malt it.
Springbank and Glen Ord produce 100% of their needs.
what are the main problems with floor malting that mean it is done less in distilleries now compared to what it used to
It imposes a limit on the amount of malt that can be made at a time and it is labour intensive.
What have most distilleries replace floor malting with
pneumatic malting systems in large scale centralised maltings owned usually by individual companies
what are the two pneumatic systems for germination that are used today
Rotary drums and kilning vessels (SGKVs)
How do rotary drums work as a means of germinating barley as an alternative to floor malting
Its charged with damp grain from steeps (From 9 to 50 tonnes of grain), it is then turned by gravity around 9 times a day. As it rotates the humidity and temperature are controlled by internal sprays and blowing air
When were SGKVs first created (Kilns for germination)
Late 1970s
As a brief overview how does Kilning work
The green malt is spread over a metal perforated floor with a furnace below that heats it up to dry it
What are the two types of kilning and how do both work
-Directly fired, which is were the gasses of combustion pass through the malt bed
-Indirectly fired, where the air is heated by oil fired burners or steam heated radiators
what kind of roofs do Kilns have that have been used since the 19th century
Pagoda roofs which cap the tapering roofs which help to draw out the heat
What is the first stage of the kilning process
the free drying phase which evaporates any moisture on the surface of the green malt
What temperature is the warm air used for the first stage of kiling (to evaporate moisture on the surface of the green malt)
60 to 65 degrees Celsius
what stage of kilning is peat used if it is going to be used
The first stage, the free drying phase
What is the maximum temperature that can be used for the first stage of kilning if peat is used and why is this
60 degrees Celsius because any higher and the phenols that lend the whisky its smoky characteristic are destroyed. The peat also adheres to the barley husks only when they are still damp
How does the temperature of the first stage of kilning affect the level of peatiness if peat is used
The lower the temperature the greater the peatiness
After the first stage of kiling (The free drying phase) what is the second phase
The forced drying stage during the which the temperature is raised to 70-75 degrees Celsius and the airflow is reduced.
By the end of the Forced drying phase of kilning what is the level of malt moisture
Around 5%
What is the third and final stage of Kilning and what does it achieve
The final stage is the cooling phase were the temperature is lowered to around 30 degrees Celsius to prevent further curing of the malt.
How long does the whole Kiling process usually take and what affects this length of time
It takes between 20 and 48 hours depending on the type of kiling process being used, the size of the kiln and the amount of malt
What is peat
It is acidic decayed vegetation made from bog plants such as sphagnum moss, heather, sedges and grasses.
what are the necessary conditions for a peat bogs development
there must be a cold atmosphere, high rainfall , poor soil drainage and/ or aeration. The waterlogged soil is unable to break down the vegetation so a thickening layer of peat begins to develop.
what happens to the peat once it is cut
It is laid out on the heather for around a fortnite surrounding the peat bog then it is stacked into small pyramids called cas bhic to throughly dry for a year
what is the term used to explain how and why peat varies from place to place
Its palaeobotany
How may a lowland peat vary from and compare to peat bogs closer to the sea
Lowland peat bogs have more vegtable matter, are looser and brun more rapidly giving off more dust whereas peat bogs close to the sea may be saturated with sea spray and may eaven contain seaweed from winter storms etc.
How is peat in Orkney graded
its got three grades, the top layer is ‘fog’ which is Rooty, the second layer is ‘yarphie’ which is small roots then the bottom layer is ‘moss’ which is the darkest layer that’s best for heat but not smoke
what are the three broad categories of peating
-lightly peated (1-5PPM)
-Medium peated (10-20PPM)
-Heavily peated (30-50PPM)
with regards to mashing articulated trucks arrive and typically bearing how many tonnes of malt
5,000 tonnes
malt is ‘dressed’ what does this term mean
It means that the malt has been passed over a reverberating wire mesh that removes clum
In terms of dressing malt before mashing what does ‘clum’ refer to
Clum is the withered shoots and rootlets produced during malting
What are the three key processes that make up malting
Steeping, germinating and kilning
from the malting process what are the main waste products used to make cattle feed
The ‘culms’ and other waste products
at the distillery the moisture levels of barley is tested, what is the maximum allowed moisture
12%
What three important factors regarding the malt is tested before mashing in the distillery
Moisture it must be below 12%
Viability for germination it must be 99% viable
Insect infestation
What process does the malt undergo when at the distillery before mashing
It goes through screening to remove any dust, stones and small grains
when needed the malt is transferred into the mill hopper then into the mill which has two sets of rollers. What do the two rollers do
One cracks the husks and the other grinds the malt
When grinding malt in a mill what are the percentages of flour, husk and grist
10% flour, 20% husk and 70% grist
What are the consequences to the proportions of flour, husk and grist not being correct
if it is too fine then the mash tun will not drain quickly enough.
If it is too coarse the liquor will drain too fast and maximum extraction will not occur
What is the grist mixed with in the mash tun to extract the maximum amount of soluble starch
Hot water
which Enzyme is also reactivated in the mash tun that would have become inactive during the other processes
Amylase which completes the conversion of starch into maltose
What are the key features of a mash tun
They are large circular vessels often with copper lids to conserve heat usually made from stainless steel or cast iron with a perforate floor through which the worts can drain
during the stage of mashing what is the liquid that is drained through the bottom called
Worts
How greatly do mashtuns vary in size and what else do they contain to aid in the process of mashing
They can vary between 1 tonne and 15 tonnes, they also have a rake on the inside which periodically stirs the mash
How many worts will a tonne of malt be expected to produce
5,000 litres
what kind of mash tun of German invention used by brewers has also been adopted by distilleries
the lauter tun/ lauter tuns
how many waters or ‘extractions are used during the mashing process in a mash tun
3
What is the first extraction/ water in mashing as in what’s its temperature and what’s its purpose etc
Its a third of the water left from the previous mashing,
It is heated to around 63/64 degrees,
Its mixed with grist in a mashing machine then added,
after around 20 minutes the rake inside stirs it,
this drains of the Worts through the underback
What is the optimum temperature for the enzymes referred to and why is it crucial temperatures stay within this region
The strike point, If the water is too hot the enzymes are denatured/ killed and if the water is too cold the amount of grist needs to be reduced.
In a mash tun what are the holes in the floor of it referred to as
The underback
What is the second extraction/ water in mashing and what temperature is it etc
Water is pumped into the mashtun at 70 degrees and it is stirred and then left for 30 minutes. It is then emptied into the underback
What is the third extraction/ water in the mashing process called, what does it do, what temperature is it etc
The third extraction is called ‘Sparge’
It goes into the mashtun at 85 degrees,
It takes 15 minutes to fill and settle,
Its then pumped into the hot water tank to be used as the first extraction for the next mash.
What approximate percentage of sugar does the third extraction of mashing contain
around 1% sugar
What is the remaining waste in the mash tun called and what is it used for
It is called draff and it is used by local farmers as wet draff for cattle feed. Alternatively it can be sent to a dark grains plant to be dried and combined with resides from wash still distillation (‘pot ale’) and compressed into cattle cake
what do the worts from the mash tun pass through as they leave through the underback
A heat exchanger
What is the worts temperature reduced to upon going through the heat exchanger and why
Their temperature is reduced to 20 degrees which is vital because otherwise the yeast would be killed and the maltose would decompose.
What is the next essential stage after mashing in the Mash tuns and what vessel is it done in
Fermentation which is done in vessels named washbacks.
what is the range in capacity in a washback
between 220 gallons(1,000 litres) and 15,178 gallons (69,000 Litres)
What are washback’s commonly made of
Larch, pine (Oregon pine also called Douglas fir is a widely used favourite) or stainless steel
Why is Douglas Fir a favourite to make washbacks out of
It grows tall and has a tight grain with few knots
Fermentation is similar in distillation and brewing with one important difference what is it
The process for whisky is non-sterile
What are the principles of fermentation
Yeast needs oxygen and it is denied this by the anaerobic conditions in the washback so it extracts it from the sugars in the wash and produces alcohol and carbon dioxide.
How much do the worts pumped into the washback fill it up to
Around 2 thirds
when is the worts referred to as a wash
When the yeast has been added to it in the washback which is usually done as the worts enter the back.
What is the first phase of fermentation in the washback called, how long does it last and what happens
The log phase, it usually lasts a couple of hours, during this phase the yeast simply adjusts to its surroundings
What happens during the second phase of fermentation
The yeast cells rapidly multiply consuming the sugars of the wash to produce alcohol and carbon dioxide. This reaction causes the wash to seethe and froth quite violently which can cause the washback rock. During this phase the temperature also rises to 35 degrees
What happens during the final phase of fermentation and how long does it last
The reaction begins to calm down as the alcohol inhibits the yeast and there is then a massive growth of bacteria.
Why is the bacteria growth at the last stage of fermentation important
It allows for a second bacteriological fermentation which predominantly comes from the malt and is basically lactic acid which helps to lower the pH.
How does the length of time left for the second period of bacteriological fermentation affect the flavour development of the wash and future whisky
A wash left for two days (48 hours) will be malty and cereal-like whilst a wash left for 60 hours or more is more complex, fruity and floral
Why must the washback’s be cleaned and sterilised between uses
A build up of bacteria can render the yeast useless
What is one of the main advantages of a stainless steel washback and the big disadvantages of wooden washbacks (Pine/ larch)
The stainless steel washback’s remain more sterile (not completely so though) and are easier to clean, and last longer than the wooden washback’s which need replacing after around 40 years.
Some insist there are advantages to the wooden washback’s over the metal washback’s what are some of these debated advantages
some believe there is a beneficial reaction between the wash and the bacteria inside the wood,
some believe well seasoned washback’s increase the esteriness of the wash,
some believe that wooden washback’s aid in insulating the fermentation during winter months
How many litres of alcohol are distillery managers expected to extract per tonne of malt and what may reduce this
420 litres worth (92 gallons) however secondary fermentation can reduce this
What stage comes after fermentation
Distillation
What is the key purpose of distillation
It separates Alcohol from the water in the wash and concentrates it
Why is the alcohol separated from the water during distillation
Alcohol has a lower boiling point than water so it evaporates before water does.
What are the vessels in which distillation occurs called and how may they be broken down and explained
They are called pot stills and are large copper pots with a wide base and tall tapering top that leads to the neck/ lyne arm/ lyne pipe which connects to the condenser.
what is the traditional means of cooling the vapours from a copper still that only 15 distilleries still have
Worm tubs. which was a large tub of cold water that had a long metal coil immersed in it that cooled the vapours and liquified the alcohol
What is the more common modern way of cooling and condensing the vapours from a copper pot still that are used by most distilleries today
Shell and tube condensers.
This is were the shell (a large cylindrical tube) contains the vapours and tubes within contain the cooling water that cools the vapours
Whisky distillation requires a pair of stills what are the terms given to the first still and second still
The first still is called the ‘wash’/’singling’ still
the second still is called the ‘low wines’/’doubling’ still
is a third still permitted for scotch whisky
Yes it is and they are occasionally used by some distilleries although not many, at least not anymore.
why are the was/ singling stills typically larger than the low wines/ doubling stills
They need to hold a greater quantity of liquid.
What are the three basic designs of stills
-‘plain’ or ‘onion’ (which is the most common)
-‘Boil ball’ shape
-‘lantern’ shape
how do the designs of stills differ
They may differ as to capacity, height, means of heating, angle of the lyne arm etc it all differs between different distilleries
how may the height of the still affect the reflux and thus the volatiles of the spirit
increased height will mean more reflux so only the lighter more volatile vapours will be collected and the heavier vapours will fallback down again.
What do some distilleries do in order to increase the reflux ensuring only light vapours are collected
they attach Purifiers and return pipes to the still head. Some will also angle the lyne arm upwards
How does the copper that makes the still aid in the quality of the spirit and how does the amount of contact the spirit have with the copper affect the new make
Copper is a purifier and it removes sulphury and vegetal compounds particularly during the first distillation.
The more contact the spirit has with the copper the lighter and purer it will be.
How does a narrow neck on a copper still affect contact of the vapours with the copper
narrow necks cause the vapours to ascend at greater velocity thus reducing their contact with the copper
Traditionally lots of stills were heated by direct firing. (Most distilleries stopped this around the 1960s/1970s) How did they stop small particles at the bottom of the stills from scorching and sticking to the base
‘Rummagers’ were fitted which were revolving arms that drag heavy copper chain mail around their bases.
During the 1960s and 1970s lots of the traditionally direct fired stills were replaced with indirect fired stills, how do these work
these are heated with steam heated coils of pans within the body of the still itself.
how much wash is charged into the first distillation still in terms of its capacity
It is charged between half and two thirds capacity
Why is the first distillation still not filled to maximum capacity
This would not allow any room for the expansion of the wash and the froth which builds up as it is heated.
when the wash enters the first distillation still what will its abv and temperature be
It will be around 8% ABV and its temperature will be between 26 and 32 degrees.
why is the first distillation still fitted with a seeing glass
So that the operator can see how it is behaving and ensure that the froth is building up to a suitable level etc
During distillation when would the operator see a need to reduce the heat on the copper still
When the froth becomes to high in the seeing glass to prevent it rising too high and carrying over the neck of the still
What is the cause in the variation for the time it takes for the wash to settle (15mins to an hour) when being transferred into the still for distillation
The length of fermentation, a wash that’s been allowed to rest and ferment fully will settle quickly by stark contrast to a wash that has not been allowed to rest and complete secondary fermentation.
What does the phrase “come in” refer to in scotch whisky making during distillation
This refers to when the wash transferred into the still has settled
how can the amount of furfurol (a compound creating an acrid and unpleasant burnt taste) being distilled in the low wines still be minimised
by gradual and carefully regulated heat making sure the froth of the wash stays at a level by the seeing glass and doesn’t rise above it
when extreme action is taken during distillation and overally unregulated intense heat is applied what deposit is increased in the neck and worm of the still that is unwanted
An oily, yeasty matter that contains furfurol (an unpleasant compound containing a burnt and acrid taste)
at what point do they stop running or heating the still whether that be with a live fire or steam
when it is at around 1% ABV
What nutritional value does the remaining waste from whisky distillation (When its around 1%ABV) have?
Its usually high in protein
What is the wastage from whisky distillation (From the first still run, low wines) used for and hows it treated
It contains around 4% solids and it is drained off and evaporated into syrup which is combined with the draff from mashing to produce ‘dark grains’ used as livestock fodder
What is the wastage from the first spirit run/ first distillation called
pot ale/ burnt ale/ spent wash
What is the approximate ABV of the low wines produced by the first distillation
21%ABV
Low wines from the first distillation at around 21% ABV are passed to what in order to increase it
The ‘low wines and feints charger’
What is the low wines ABV increased to by being passed through the low wines and feints charger
28% ABV
what is added to raise the ABV of the low wines from 21% to 28%
by the heads and tails left there from previous wine distillations
Why must the low wines ABV be increased to 28% before the second still/ spirit run
If the low wines are below this then they would not fractionate
A large amount of foreshots and feints circulate again and again but are never actually used in the spirit, why then is it important that are still kept and recirculated
Its essential to making the low wines a high enough ABV that they can fractionate properly during the second distillation/ spirit run
what is the purpose of second distillation
It further purifies the spirit into ethyl alcohol and water as well as importantly less pure alcohols and oils
What are the main less pure alcohols and oils that are predominantly compounds of hydrogen, oxygen and carbon found in the spirit produced by second distillation
Esters, Aldehydes and furfurol
What is the collective term used for less pure alcohols and oils found in whiskies after the second distillation
Congeners (UK) or congenerics (USA)
what is the collective term that describes the compounds responsible for most of whiskies flavours
Congeners (UK or Congenerics (USA)
What are foreshots in second distillation
this is the earliest of the distilled spirit out the still that is separated which also known as heads
What are the feints in distillation
This is the last of the spirit produced from second distillation that is separated also known as tails
what does the cut refer to in terms of second distillation
This is the spirit that is produced after the foreshots/ heads and before the feints/ tails. It is also referred to as the heart
what are the predominate compounds and impurities distilled off in the foreshots and feints
Impure alcohols
why must the cut be precisely judged
In order to prevent too much of the congeners or undesirable compounds being passed over into the spirit which could render it undrinkable
What is the rough ABV range of the foreshots from distillation and what temperature are they produced at
75-80%ABV and they are produced at around 84 degrees Celsius
How are the foreshots tested for impurities and when do the foreshots begin to make the cut
Impurities are tested by adding water. If it goes cloudy then it is impure and classed as foreshots. When tested and no longer cloudy the flow is redirected to be saved by manipulating a spout in the spirit safe
What is the name of the test used to test the impurities within the foreshots from distillation
A demisting test
How is the ABV of the foreshots and distillate tested
Using a hydrometer
for as log as the distillate is proven to be impure by the demisting test were is its flow directed and why
it runs into the low wines and feints receiver so that it can be used on the next run of low wines to increase their ABV to 28%
at the point the foreshots end what is the rough ABV that the cut starts at
Around 72-75% ABV
how long do the foreshots usually run for before the cut can start being made
Around 15-30 minutes
What do temperatures rise to after the foreshots during the run and what does the rate at which the still is run affect
100 degrees Celsius, the rate of the still being run will impact the purity and flavour of the finished product
what is the boiling point of the de-alcoholised low wines
100 degrees Celsius
what valuable flavour enhancers can be found in the early stages of the cut and late stages of the foreshots
desirable aromatic ester that are fragrant, fruity and like that of pear drops, bananas and roses.
By estimate how many esters are present in the early cut of distillation
At least 100
which are the most important esters from an aromatic view during the early cut of distillation
Isoamyl acetate and ethyl caprylate.
What do the feints provide the distillate/ cut in terms of flavours and aromas
they are biscuity, porridgey and leathery. They then breifly become reminiscent of honey but after that as they grow in intensity they can become reminiscent of sweat, stale fish and sick
what happens to the esters as the intensity of the feints increases
They decrease
what are the chemical terms for the nicer flavour compounds at the start of the feints compared to the nastier compounds towards the end
organo-nitrogen compounds are the starting nicer compounds
organo-Sulphur compounds are the nastier compounds towards the end of the feints
how are the aromatic properties of sulphur/ Organo-sulphur compounds often described as
sulphury, rubbery or egg-like
Why is the stillman during the second still run obliged to stop making the cut even though the distillate is still of a high ABV
The stillman must make the cut to avoid the negative and unpleasant compounds being passed on from the feints as they become more intense.
what will make the future resulting whisky more feinty and robust during the second spirit run of distillation
if the feints are left to run into the cut for longer before it is made
why is it important not to completely cut out the feints
the cut would lack a lot of compounds that can provide it flavour and character
at what progression during the second spirit run do phenolic compounds become present in the distillate
into around 1/3rd of the cut
What makes phenolic compounds in the distillation process different to others
When they appear around a 1/3rd into the cut they do not rise in intensity nor do they noticeably decline
what are the feints directed into and what happens to them
They are directed to the low wines and feints receiver and they will undergo redistillation and make the next low wines at least 28% ABV
What is the remaining ABV of the second still once cut has been made and distillation is done
Around 1% ABV
What is the waste from the second spirit run called
‘Spent lees’
what fraction of the spirit produced by the process of secondary distillation are the feints and spirit
1/12th or 1/13th
What is the average strength of the spirit after the second distillation that goes into the intermediate spirit receiver
70%ABV
What is the minimum aging requirement for scotch whisky
Three years
As the spirit cannot be legally named whisky until three years what is it called and referred to as
New make, or clearic by those who make it
what ABV is the new make commonly reduced to before aging
63.5%ABV, the optimum strength for maturation
if a distillery chooses to fill a cask at a higher strength than 63.5 ABV what is the consequence
The spirit will take longer to mature
what is a rough percentage for how much flavour from the whisky is due to the wood its aged in
Approximately up to 80%
what things might affect the flavour whilst the whisky is aging as smaller variables
The size, nature and history of the cask, the style of warehouse it is in, its geographical location and the surrounding microclimate, and of course the length of time left to age
since 1990 what has been a legal requirement for all casks that age scotch whisky
They must be made of oak
what are the two most commonly used types of oak for whisky maturation and what are their latin names
American white oak ‘Quercus alba’
European oak ‘Quercus robur’
how old must a tree be in order to be suitable for making casks
80 years old
What makes oak ideal for maturation
it contains cellulose, Hemicellulose, lignin, tannins and wood extractives and it also facilitates oxidation.
what are the benefits of cellulose from the oak in terms of aging
Not really any it contributes very little
What are the benefits of hemicellulose in the oak in terms of aging
It caramelises which adds sweetness and colour
What are the benefits of lignin in the oak in terms of aging
Its a good blending agent and pulls the flavours together increasing complexity as well as adding vanilla-like notes
what are the benefits of tannins in the oak in terms of aging
they produce astringency, fragrancy and delicacy
What is meant by wood extractives
What was aged prior in the whisky cask such as bourbon or sherry etc
What are the benefits and importance of oxidation in terms of aging and maturation
It removes harshness, increases fruitiness and adds complexity.
What is the requirement for a bourbon to be designated a straight bourbon
It must be filled into newly charred oak barrels
Why are second fill casks primarily used for aging scotch whisky in comparison to first fill bourbon casks
First fill casks imparts a heavily dominant woody flavour and aroma which is undesirable in scotch whisky
before the 1960s what kind of oak were sherry casks predominantly made from
American oak
what percentage roughly represents the number of ex-bourbon casks that are used for scotch
90%
What are the two types of ex-bourbon casks
After-bourbon barrels and Re-made hogsheads
What are after-bourbon barrels also known as, what is their capacity and how are they transported
‘American standard barrels’ with a capacity of 180 to 200 litres. They are usually transported whole
What are Re-made hogsheads also known as, what is their capacity, how are they transported and what else about them is important
They are also called ‘dump hogshead’, they have a capacity of 250 litres. They are transported as a bundle of staves known as ‘shooks’.
Five American standard barrels/ after bourbon barrels create three Hogshead barrels.
what is the most common type of sherry cask followed by the second most common
Oloroso sherry followed by Fino sherry
What does the term Shooks refer to
The bundle of staves that once made a bourbon barrel that are transported to Scotland and remade into hogshead barrels that have a capacity of 250 litres
What is the capacity of traditional ex-sherry casks and butts and what makes them both different
They both have a 500 litre capacity. Traditional ex sherry casks are longer and narrower
how long are sherry casks typically seasoned for
one to four years
What are some ex-wine casks typically seasoned with and what have most typically aged prior to whisky
Port, Madeira, Burgundy, Rhone, Sauternes etc
What does the term finishing casks refer to
This is when whisky is held inside a cask such as an ex-wine cask for a limited period typically to round it off and add an extra layer of flavour. The length of this ‘finish’ can vary dramatically
what basic ratio determines the rate at which the spirit will mature
Volume to surface area ratio
how will the size of the cask affect the rate of maturation
The smaller the cask the faster the maturation
how does the price of ex-sherry casks compare to bourbon and how do their longevity compare
Ex-sherry casks are typically 5 times more costly that ex-bourbon barrels and they typically last far longer as they can be used for longer
What percentage of casks imported into Scotland are ex-bourbon casks
93%
What is the average stock of casks in Scotland
Around 20 million
what is the umbrella term for the three vital functions during maturation
mechanisms
What are the three mechanisms during maturation
Additive, Subtractive and inter-active
What is the additive mechanism in maturation responsible for
The addition of desirable flavours to the spirit
What is the subtractive mechanism in maturation responsible for
It removes unwanted flavours
What is the inter-active mechanism in maturation responsible for
This allows the spirit to interact with its environment loosing harsh alcohols and developing complexity via oxidation. This mechanism isn’t fully understood
When making barrels for aging whisky why must the staves be toasted and not steam heated
Toasting the staves causes the alteration of chemical molecules in the wood like hemicellulose and lignin and wine reside etc that impart flavour and colour onto the whisky. If it was steam heated it wouldn’t do any of this and the wood wouldn’t impart anything.
American oak bourbon barrels are charred prior to use what is the benefit of this
It increases surface area to volume ratio, it allows for increased interaction between the spirit and the wood, the charcoal inside also acts as a purifier and removes unwanted distasteful compounds i.e sulphurous ones
What does a first fill cask refer to
A cask that has not been used to age whisky, regardless of what it may have aged prior such as bourbon or sherry etc. Thereafter it becomes a refill cask when used to age a second whisky and so on
What does the term ‘active’ mean relative to casks and when are casks most active
Active means that it has a lot more in it and will impart a lot more colour and flavour onto the spirit etc. The most active casks are ones that are first fill and have had limited use
for longer maturation what kind of cask is preferable
A refill cask
what are most of the casks used within the scotch industry in terms of refill vs first fill
Most are refill
What do you need to know about the ‘Gorda’ cask
Its also called a ‘bodega butt’ and stores around 600 litres
What do you need to know about the ‘pipe’ cask
It is formerly used to age port. It can store 500 litres
What do you need to know about ‘puncheons’ as a type of cask
They can store 545 litres
What do you need to know about the ‘butt’ cask
It is formerly used to age sherry. They store around 500 litres
What do you need to know about the ‘dump puncheon’ cask
It stores 460 litres
What do you need to know about the ‘hogshead’ cask
its the most commonly used type of cask. It stores 250 litres. its also called ‘re-made hogsheads’ and ‘dump-hogshead’
What do you need to know about the ‘barrel’ cask type
Usually referred to as ‘American barrel’ It stores 180 litres
What do you need to know about the ‘Kilderkin’ cask
Also called ‘Kinken’ they store 82 litres
What do you need to know about ‘quarter’ casks
They are also called ‘firkin’ and are usually around 45 litres (9-10 gallons)
What do you need to know about ‘Anker’ casks
They hold around 45 litres (8-10 gallons)
What do you need to know about ‘octave’ casks
They hold 22.5 litres (5 gallons)
When does a cask become ‘exhausted’
After around 3 or 4 refills depending on how long it has aged the contents they will loose their activity
How can a cask be ‘rejuvenated’
Through a process called ‘de-char re-char’ where they are reamed out and re-toasted which activates the layer of wood beneath the previous char layer. However a recharged barrel will not mature its contents in the same way as it used to.
What are dunnage warehouses
They are low stone-built and earth-floored warehouses with casks racked three high
In modern racking and warhouse storages how high can casks be stacked to
Up to 12 high
Which distillery has the largest modern warehouse for aging whisky and how big is it
Macallan, it covers half an acre and stores over 70,000 casks
What is the angels share and how much whisky is roughly lost each year in terms of total volume
Angels share is the evaporation of the spirit inside the cask that is able to leave it resulting in the total volume and ABV decreasing over time. Around 2% is lost each year
In a dunnage warehouse where the air is humid and circulating over the course of ten years what is the approximate amount of ABV decrease
Around 4 to 5%ABV
In a dunnage what decreases faster the volume or the strength and by contrast in a modern warehouse which decreases faster
In a dunnage the ABV decreases faster than the volume. In a modern warehouse the opposite is true and the volume decreases faster than the ABV
What is an example relative to Islay that shows how the region and specific geographical location of maturation affects the aging spirit
Sea spray and other like things permeate the air and can impart a salty, brininess onto Islay Whiskies
