Unit 4 Flashcards
(32 cards)
General vodka definition
- raw material of agricultural origin.
- reduced character/aroma/taste from distillation or charcoal treatment.
- (sometimes) max defined levels of trace impurities
Yeast considerations for vodka production
- Efficiency
- high gravity wort/cascade fermentation.
- tolerant to high osmotic stress, temp, and alcohol
- flavour is not a concern.
Potential component steps in NGS production
Primary Distillation/stripper/rectifier
Extractive Distillation/hydro-selection
Secondary Distillation/stripper/rectifier
Fusel oil recovery
Alcohol recovery from offtake streams
Methanol removal
4 methods for neutral spirit purification to produce vodka
Re-distillation (softens)
Hydro-selective distillation (higher alcohols)
Demethylising column.
Activated carbon treatment.
Raw materials used to form activated carbon
wood, coconut husks, bamboo, peat.
3 methods of activated carbon treatment
Powder
Packed columns
Filter sheets (small volume only)
What is juniper oil comprised of?
Terpene hydrocarbons
(alpha and beta pinene, myrcene, sabinene, limonene)
Coriander terpenes
Linalool, pinene
Parts of citrus fruit used in gin
Exocarp
(Not mesocarp & endocarp)
Why is orris root used in gin?
As a ‘fixative’
(equalises the vapour pressures of volatile compounds in a mixture)
Factors in Juniper assessment
Size
Colour
Year
Ripeness
Softness (squash easily)
Region
Juniper storage
4-12 degrees C
Humidity 50-75%
London Dry gin regulations
NGS - agricultural origin, max 5g/hL methanol.
Distillate min 70% ABV
Sweetening less than 0.1g/L sugar
No colour
No ingredients apart from water
Minimum strength of London Dry
37.5% ABV
London dry typical ingredients (per L 50% charge)
10-15g Juniper
5-7g Coriander
0.1-0.5g Peel
1-2g Angelica
0.1-0.2g Orris
Typical botanical amount per L in a gin charge
10-30g/L
Best type of gin stills
Jacket heated/double boiler
Botanical access
Easy cleaning/large discharge pipe
Basket option
Carterhead still
Botanical in a cavity in the path of the vapour, not in the still or neck
Typical gin fractions
Heads 0.5-1%
Hearts until 50-60%
Tails - To financial ‘end’
5 methods of non-distilled gin production (botanical oils)
Steam stripping
CO2 extraction
Vacuum distillation
Pressing
Solvent extraction
How must essential oils be stored?
- UV inhibited
- Cool
- Dry
- 6 month shelf life
Signs essential oils have gone off
Colour change
Increased viscosity
Aroma change (intensity)
Off flavour/aroma
Transparency
4 factors affecting maceration efficiency and flavour
Time
Surface area
Temperature
Spirit concentration
3 As
Aquavit
Absinthe
Anise
