2 - Factors Affecting the Style and Quality of Spirits Flashcards
From what can spirits be made?
Anything of agricultural origin that contains carbohydrates
List the four key stages common to production of all spirits
Processing the raw material
Alcoholic fermentation
Distillation
Post distillation operations
How does ‘overproof’ relate to ‘proof’?
It’s from a separate, antiquated system
Summarise distillation
Takes place in a still
Alcoholic liquid is heated
The liquid boils and turns into vapours
The vapours are condensed and collected as new liquid
What is the aim of distillation?
To select and concentrate individual parts of the alcoholic liquid and leave others behind
What is a common level of concentration taking place in distillation
10% abv to 75% abv
How high can distillation take a spirit in abv?
96%
Lower abv spirits will have…while higher abv spirits will have…
Greater aroma intensity and complexity
Lower aroma intensity and complexity
What is a fraction?
Any one of hundreds of individual chemicals that make up an alcoholic liquid
What is a congener?
A fraction that has an aroma detectable by the human nose
What is the aim of most post-distillation operations?
To ensure that a spirit is sold with the correct colour, aroma, sweetness and alcoholic strength
What’s the aim of processing the raw material?
To create a sugary liquid
How are sugars stored in the raw materials for spirits?
Fermentable sugars
Complex carbohydrates
In what materials are the sugars readily fermentable?
Grapes and sugar cane
Give two examples of raw materials in which the sugars are complex
Grains and agave
Besides sugars, what else do raw materials offer? Give examples
Aromas
Blue agave - earthy, peppery aromas
In which spirit are all congeners removed during production?
Vodka
What must a distiller use if they want to produce high quality spirits?
High quality raw materials
Why are high quality materials important?
Small defects can be concentrated by distilation
What is the principal aim of fermentation?
To create an alcoholic liquid called ethanol
What is the common range of abv created by fermentation?
8-10%
Besides the typical by-products of fermentation, what else can be created?
Many congeners/fractions
What are the two groups of congeners with which we’re concerned?
Other alcohols
Esters
What are the main other alcohols produced besides ethanol?
Methanol
Fusel alcohols
What are the advantages and disadvantages of the other alcohols?
They can add complexity in small amounts
The aromas can become unattractive
Describe esters
They have an attractive fruity smell
When are the greatest number of congeners produced?
During fermentation
How might a distiller reliably produce the right amount and type of congeners for their spirit?
By using specific, bought-in yeasts
Where do ambient yeast come from?
In and around the distillery
What’s the argument in favour of using ambient yeast?
They argue that the fermentations can be just as consistent and the final product is more complex
Give notable examples of producers who use ambient yeast
Rum producers
Producers of agave spirits
What’s the aim of distillation?
To concentrate and select ethanol and some of the congeners present in a fermented alcoholic liquid
What characteristics are shared by all newly distilled spirits?
Water white
Colourless
Dry
Summarise the four stages of distillation
Liquid made of ethanol and water
Liquid heated
The more volatile ethanol evaporates at a cooler temperature
The vapour is collected and condensed back to a liquid that’s higher in abv than the original liquid
What is present in steam?
Water droplets
Water in gas form
What is reflux?
The interaction between vapour and gas from an alcoholic liquid
Explain reflux
When gas and vapour interact, gas and vapour reforms. As ethanol evaporates more easily, reflux makes the gas more alcoholic
What is rectification?
The rise in alcohol as a result of reflux
Besides abv, what else is affected by rectification?
Aroma intensity
Nearly all pot stills are made from…
Copper
Why is copper often used in pot stills
It’s easy to shape
It’s a good heat conductor
What’s the swan neck?
It’s the section of tubing between the pot and the still head
What’s the Lyne Arm?
The tubing that links the still head to the condenser
What does the Condenser do?
Converts the vapours back to liquid
How are most modern stills heated?
Steam
How might steam be used to heat a still?
Internal coils
External jacket
What’s the traditional method for heating a still?
A gas burner
What’s the most common type of condenser?
Shell and tube condenser
How does a shell and tube condenser work?
The vapour enters the top and comes into contact with pipes that contain a coolant
The cold tubes cause the vapours to condense back into a liquid
The liquid flows out the bottom of the condenser
What’s the other type of condenser?
Worm tub condenser
…is a batch process
Pot still distillation
Describe spirits from pot stills
Low level of rectification
Characterful
Medium to pronounced aroma intensity
How many times must a fermented alcoholic liquid be distilled to produce a spirit?
At least twice
What’s the aim of the first distillation?
Remove some of the water and non-volatile fractions from a fermented alcoholic liquid
Collect as many volatile fractions as possible
What is/are the low wines?
The liquid produced by the first distillation
What’s the normal % range of low wines?
Between 25% and 30%
Describe the stages of the first distillation
Still is filled with alcoholic liquid that’s 10% abv
Liquid is boiled and vapours rise up the still into the condenser
The liquid from the condenser is collected for several hours until abv of the flow has fallen to 1%
Watery liquid in the still is discarded
What would be the result if a distiller simply ended at 30 minutes?
The liquid would be alcoholic enough to be sold as a spirit
The vast majority of the ethanol from fermentation would be left in the pot
Vast majority of the recognisable congeners would be left in the pot
What’s happening to the alcohol level of the liquid in the pot as distillation goes on?
ABV is reducing
Why does the distiller keep running the still when so much water and other volatile fractions are being collected?
In order to capture all the ethanol and positive congeners
What sort of percentage is the low wines?
25-30%
What’s the aim of second distillation?
To create a liquid the distiller can ultimately put on sale
To concentrate the ethanol and some of the congeners
List the stages of second distillation
Filled with low wines and heads/tails of previous distillation
Liquid is boiled
First liquid from condenser has solvent aromas (heads). This is collected in a tank
After 10-15 minutes, flow is redirected (heart)
Heart collection can take several hours
Final abv in tank is about 75%
When aroma becomes cheesy/plasticky, flow is redirected to head tank (now tails)
Flows is stopped after several hours or when flow becomes 1%
Liquid from still is discarded
What is a group 3 fraction?
Fractions with a boiling point much higher than ethanol (water, 100C+ etc.)
What is a group 1 fraction?
Fraction with a boiling point much lower than ethanol
What is a group 2 fraction?
Ethanol and fractions with a similar boiling point
What is the relative proportion of group 1 fractions in a newly alcoholic liquid?
Very low
Why are pot-distilled spirits more characterful/pronounced?
It does not precisely separate other group 2 fractions from ethanol
Why might a distiller not want to cut out all heads/tails?
Because they can add depth and complexity to a spirit
The group 1 and 3 liquids contain a lot of ethanol (so they may be re-used)
What are the two main disadvantages of using pot-stills?
They’re batch operated (laborious and inefficient)
Unable to produce highly rectified spirit
How are column stills typically heated?
Using steam via heat exchangers
What are column still plates designed to do? How?
Maximise reflux
They send more volatile fractions up the still and less volatile fractions down the still
Name a common type of plate found in many column stills
Bubble cap plate
Describe how plates work in four steps
Vapours rise into the centre of the plate
Pressure from the vapours forces vapours through the bubble cap into the boiling liquid, forcing reflux. The vapours’ heat keeps the liquid above at the boil
More vapours rise to the cap above. These contain a greater concentration of group 1 fractions
The liquid left behind on the plates contains heavier fractions and flows down via the downcomer
Some column stills can be run…
Continuously
What’s the aim of the distiller when running a continuous column still?
To manage the flow of liquid and vapour through the still so they can keep collecting a spirit with a consistent style and quality
Describe the stages of continuous distillation
Constant flow of pre-heated (as close to boiling as possible) alcoholic liquid entering in the bottom half
Constant vapour rising and liquid falling
Group 1 fractions will pass out at top (heads)
Group 2 fractions/hearts removed from a few plates below the top
Group 3/tails drained off near the bottom
Liquid waste taken at the base
What is meant by a column still being in balance?
The volume being fed in is equal to the volume being collected
Where any fraction reaches its peak of concentration will depend on…
Its volatility
Why would group 3 fractions be at their peak concentration further down the still?
Being the heaviest/least volatile fractions, they require the most energy to stay as a gas
Give examples of spirits that might be drawn off at 75%
Armagnac
Rhum agricole
Bourbon
How might the aromatic intensity be described of a spirit drawn off at 90%? Give examples of such spirits
Light
Light marks of rum
Scottish grain whisky
How might a spirit be known if it’s drawn off at 95-96%?
Neutral
For which region is 95% the minimum required abv to be called a neutral spirit?
USA
What is the minimum abv requirement for a neutral spirit in the EU?
96%
What’s the intention with post distillation operations?
To ensure a spirit has the required colour, aroma, sweetness and alcoholic strength
What are the four major groups of post-distillation operations?
Storage and maturation in oak or inert vessels
Adding flavours other than oak
Blending
Finishing
What is char?
The name for the inside of a barrel if it’s been heated so intensely that it briefly caught on fire
What is toast on a barrel?
Gentle heating of the inside of a barrel (it has never caught fire)
Name four ways in which any oak barrel can affect the character of a spirit
Add colour and flavour
Oxygen and time
Evaporation and concentration
Remove harshness
Describe the stages of colour in a spirit when it’s been oaked
Lemon, gold, amber
List the most common descriptors for oak flavours
Vanilla, coconut, cinnamon, clove
How might aromas such as leather and mushroom be created? How are these sorts of flavours/aromas known?
When congeners from the oak and spirit react with oxygen over time
Rancio
What is the angel’s share?
The part of a maturing spirit that’s lost through evaporation over time
What does evaporation do to a spirit?
Concentrates remaining congeners
How is harshness removed by oak maturation?
Spirit moves into and out of the oak, passing through the layer of carbon
The carbon captures congeners and removes harsh textures
Why is barrel quality management important?
It can give a spirit much of its flavour
What three choices can a distiller make regarding barrel maturation?
Barrel age
Previous contents
Warehouse temperature
A barrel will give most of its colour and flavour when…
It’s brand new
When any barrel is emptied…
Some of the liquid will remain absorbed in the staves
What may previous barrel contents do to a new liquid in the barrel?
It will come out again, adding flavour and sometimes colour
Where is previous barrel contents most famously used among spirits?
Finishing some Scotch Whiskies
How might the movement of liquid in and out of staves be controlled?
Through controlling warehouse temperature
Warehouses are always hotter…
At the top
Why might oak maturation not be a suitable choice for everything?
Because it has such a significant impact on the flavour and the colour
What are inert vessels usually made from?
Steel or glass
List three different ways in which inert vessels might be used
Storage
Maturation
Preservation
What happens to a spirit if it’s stored in an inert vessel for several months? How does colour change?
It becomes smoother, more mouth-filling and more complex
It doesn’t
How are spirits described after spending months in inert vessels? Why?
Aged
They’ve gone through a managed period of change
How might inert vessels be used for preservation?
Glass demijohns can stop further oxidation and concentration for blending components in e.g. Cognac
What proportion of spirits are blended?
The vast majority
What are the two main blending aims for a distiller?
Consistency
Complexity
Why might a blender add small amounts of very aged spirits to a younger one?
To create a balance and complexity that neither spirit is able to achieve on its own
How is a blender most easily able to achieve his two main aims?
By ensuring they have access to as wide a range of different ingredient spirits as possible
How might different ingredient spirits be made for blending?
Made in pot or column stills
Spirits of different ages
Spirits matured in different conditions
Why might blenders not be able to use an exact recipe?
Spirits can change or become unavailable over the years
What is finishing?
The process of preparing a spirit for bottling and sale
What are the main four finishing options for a spirit producer?
Adding water
Adding colour
Adding sugar
Filtration
Where is 37.5% abv the legal minimum bottling strength for most spirits?
The EU
Where is 40% abv the legal minimum bottling strength for most spirits?
The USA
How are spirits brought down to their desired bottling strength?
Dilution with completely pure water
Why is colour added to oak matured spirits?
For batch consistency
What is caramel colour?
A food grade colouring material
How much caramel colour is needed for the required effect in most cases?
Very little
What flavours and aromas accompany caramel colour?
Burnt sugar
Bitterness
What is true of all newly distilled spirits?
They contain no sugar
How will a distiller most commonly filter their spirit? What’s this called?
They will chill the spirit, let a haze form, then filter it out
Chill-filtration
What is controversial about chill-filtration?
Some producers believe the process affects flavour
What is a less common form of filtration?
Charcoal filtration
Why is charcoal filtration considered more extreme?
It can filter out some congeners as well as colours
Give an example of spirits where charcoal might be used to filter out colour
Some rums
Why do some producers actively avoid filtration?
They believe it always takes too much away from the character of the spirit
How might unfiltered spirits be labelled?
Unfiltered
Non-chill-filtered
