Caballero B. (ed.) Encyclopaedia of Food Science, Food Technology and Nutrition. Ten-Volume Set

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value (in mmd O

per kg fat) should not be greater

than 0.2. Coliforms should be absent in 1 g of prod-

uct. It must have a clean, bland taste with a smooth

and fine-grained structure.

Methods of AMF Production

0044 Only well-equipped dairy plants can produce pure

milk fat to international standards, and the

production methods, of which there are several, are

classified in terms of three basic processes: (1) direct;

(2) semidirect; and (3) indirect.

0045 Direct process In the direct process, pure milk fat is

made directly from milk. In a typical process, milk is

pasteurized, using a regenerative process of heating,

and separated into skimmed milk and cream (usually

containing 35% fat). The cream is pumped through a

plate pasteurizer, using a temperature of at least 75



for 15 s, and cooled by regeneration to 55–58



C. It is

then pumped to a clarifixator where it is concentrated

to a very high fat content, and the emulsion breaks.

The clarifixator has two outlets, one for skimmed

milk and the other for oil. The oil phase (80–85%

fat) is pumped, via a balance tank, to the fat concen-

trator, and, after preheating to 90–91



C in a plate

heat exchanger, is pumped to a vacuum chamber for

dehydration to below 0.1% moisture. The finished

product, extracted from the vacuum chamber, is

cooled to 21



C before packaging in large metal cans

or drums. Nitrogen sparging of the AMF is carried

out by injecting nitrogen gas at a pressure of 100–

140 kPa into the oil-line after the final dehydration

stage.

0046 Semidirect process In a semidirect process, cream is

fed, with the help of a positive displacement pump, to

a continuous buttermaking plant. The butter granules

then pass to a jacketed, hopper-dough pump, to a

combination in order to condition the fat and

make melting by a heat exchanger possible. Using a

centrifugation system, desludging is carried out to

remove all the solids and most of the aqueous phase.

The semidry oil plus added water is returned to a heat

exchanger for temperature adjustment. The contents

are, thereafter, fed to another centrifuge which

removes the last traces of solids and reduces the mois-

ture content of the fat to less than 0.5%. Finally, the

oil is passed through a vacuum vessel to reduce the

moisture to less than 0.1%.

0047Indirect process In the indirect process, butter is

used as a raw material. Butter is melted in steam-

heated melting kettles or revolving plate-type

‘melters.’ The plate rotates at 150 rpm, throwing the

molten butter on to the wall of the melter, where it

drains into a collection trough. The molten butter is

passed through a stainless-steel mesh filter to remove

any extraneous matter, such as wrapping material,

and is then pumped to the agitated, water-jacketed

holding vats at 55–60



C. Neutralization, if required,

is carried out prior to separation in the holding vat

and before pumping to centrifuge. Molten butter is

pumped to a Sharples centrifuge for reduction of the

total SNF and water content to about 0.5–0.8%. Fat

from the centrifuge is washed with hot water at 82



The fat–water mix is then passed to a battery of six

Sharples vapor-type super centrifuges, or a set of oil

clarifiers, to accomplish the complete removal of SNF

and water. The oil is finally vacuum-treated to

remove the remaining moisture.

Uses of AMF

0048AMF can be utilized in a number of ways. It is par-

ticularly suitable for use in warm climates and for

export. It is used widely in making recombined milk

and recombined milk products, and as an ingredient

in many processed foods of commercial value. In

addition, AMF can be converted into ghee or flavored

with simulated ghee flavors.

Conversion of AMF into Ghee

0049In many countries, surplus milk fat is conserved in the

form of butter oil, rather than butter, because of

savings in cold storage capacity and the anticipated

long shelf-life at ambient temperature. AMF lacks the

characteristic flavor, aroma, and texture which are

otherwise required in ghee, although the chemical

composition is almost identical to that of ghee. A

scheme has been suggested for producing ghee from

butteroil by the addition of skim milk dahi (20%

w/w) or dahi powder (5% w/w) to butteroil and heat-

ing the mixture to 120



C for 3 min. It is also possible

to incorporate ghee flavor concentrate in various

proportions to butteroil. A synthetic flavor was

tbl0002 Table 2 Composition of milk-fat products

Product Fat

(%)

Moisture

(%)

Maximum

peroxide

value per

kgoffat

Fat-free

dry

mass

FFAs

(maximum %)

Anhydrous

milk fat

Grade I 99.8 0.1 0.2 0.2 0.3

Grade II 99.3 0.5 0.3 0.7

Grade III

(butter oil)

99.6 0.3 0.8 0.4

Dry butter 96.0 0.3 4.0

Ghee 99.5 0.5 3.0

FFAs, free fatty acids.

2888 GHEE

constituted to induce a ghee-like flavor in butteroil.

The synthetic mixture consisted of d-(G-10)-lactone

(3 p.p.m.), d-(G-12)-lactone (15 p.p.m.), decanoic

acid (5 p.p.m.), and kenanone-2 (10 p.p.m.). The

shelf-life of flavored butteroil was improved from

10 weeks to about 6 months by adding BHA (0.02%).

A ‘cooked’ flavor can be induced by heating the ghee

residue (10%) with butteroil at 120



C for 30 min.

See also: Antioxidants: Natural Antioxidants; Synthetic

Antioxidants; Buffalo: Milk; Cholesterol: Properties and

Determination; Fatty Acids: Properties; Dietary

Importance; Flavor (Flavour) Compounds: Structures

and Characteristics; Lactic Acid Bacteria; Milk: Dietary

Importance; Oxidation of Food Components;

Phospholipids: Properties and Occurrence; Sensory

Evaluation: Taste; Sheep: Milk; Triglycerides:

Structures and Properties; Vitamins: Overview

Further Reading

Abichandani H, Sarma SC and Bector BS (1991) Continu-

ous ghee manufacture – an engineering solution. Indian

Food Industry 10(4): 35.

Rajorhia GS and Sherwon JW (1986) Effect of processing

conditions on the melting properties of ghee. Indian

Dairyman 38(8): 381.

Rama Murthy MK (1980) Factors affecting the compos-

ition, flavour and textural properties of ghee. Indian

Dairyman 32: 765.

Ray SC (1959) Prestratification Method of Ghee Making.

ICAR Bulletin. New Delhi: Indian Council of Agricul-

ture Research.

Wadhwa BK and Jain MK (1985) Simulation of ghee fla-

vour in butter oil with synthetic flavouring compounds.

Journal of Food Science Technology 22: 24.

Wadhwa BK and Jain MK (1991) Production of ghee from

butter oil – a review. Indian Journal of Dairy Science

44(6): 372.

GIN

Contents

The Product and its Manufacture

Composition and Analysis

The Product and its

Manufacture

R I Aylott, Tillyrie, Ramoyle, Dunblane, UK

Background

0001 Gin is a distilled spirit drink. It is a colorless liquid

containing at least 37.5% alcohol that has its flavor

principally derived from juniper berries. It is usually

mixed for drinking with tonic water, ice and lemon,

or with other alcoholic beverages such as vermouth to

make cocktails such as dry Martini.

0002 Distilled gin is traditionally made by distilling alco-

hol in the presence of juniper berries and other botan-

ical ingredients. Coriander seeds are usually included,

together with ingredients such as angelica root, herbs,

and orange and lemon peels. As the alcohol boils in

the gin still, it extracts flavors from botanical mater-

ials, and these condense with the alcohol in the distil-

late. The alcoholic strength of the gin distillate simply

has to be reduced with water down to the required

bottling strength, and the gin is ready. There is no

maturation process in wooded casks as is used with

brown spirits such as whisky, brandy, and rum.

0003Gin as an English product dates back to the late

seventeenth century. It was introduced into England

by soldiers returning from wars in the Low Countries

where wine and grain spirits were flavored with

juniper to make ‘jenever’ (a corruption of the French

word ‘genievre’). In those days, the quality of the

available alcohol was poor compared with modern

alcohol, and the juniper flavor no doubt served to

make the pungent alcohol more palatable.

0004When gin was introduced into England, the most

popular alcoholic drinks, other than home-produced

beers, were wines and brandies from France. The

Dutchman William of Orange became King of Eng-

land. Strong anti-French anti-Catholic interests at

that time helped push the 1690 Distilling Act through

Parliament. This act banned the import of French

wine and brandy and encouraged the distillation of

spirits from grain. Further changes in laws and fash-

ion led to a vast increase in the production and con-

sumption of gin.

0005The early eighteenth century was the time of a

gin craze in England. Gin was often sweetened with

sugar or glycerin and was known as ‘Old Tom.’

Consumption is reported to have increased from 0.5

million gallons in 1689 to 5 million gallons in 1727.

By 1733, 11 million gallons were produced in London

alone – that was 14 gallons a year for each resident.

GIN/The Product and its Manufacture 2889

Production in London, whose population was

500 000, increased to 20 million gallons by 1743.

This enormous consumption of cheap liquor obvi-

ously had major social effects, especially on the poor

people who already lived under bad conditions. Par-

liament tried to control consumption with the Gin

Acts of 1736 and 1743. Prices rose, and this had the

effect of reducing demand.

0006 Quality started to increase, and the end of the

eighteenth century/early nineteenth century was the

time of the foundation of many of the firms carrying

the popular brand names of today. Gin became so-

cially acceptable, being drunk by the servants of the

British Empire. Export trade developed, later involv-

ing overseas distilling and packaging operations.

0007 Modern neutral alcohols are much purer than their

equivalents in earlier centuries and now enable the

sensory characteristics of juniper berries and other gin

botanicals to be the primary source of gin flavor.

These unique qualities help to make gin the inter-

nationally popular spirit it is today.

Definitions and Regulations

0008 Gin and other major distilled spirits are defined in

law. These definitions serve to protect the interests of

consumers, protect gin as a generic product, and pro-

tect the interests of the gin distiller.

0009 The law within the European Union (Council Regu-

lation No. 1576 of 1989) is particularly important, as

that is the definition where the generic product origin-

ated. In summary, a drink may be called gin if it is

produced by flavoring ethyl alcohol of agricultural

origin with natural and/or nature identical flavoring

substances so that the taste is predominantly that of

juniper. Distilled gin is produced by redistilling the

alcohol in stills traditionally used for gin in the pres-

ence of juniper berries and of other natural botanicals

provided that the juniper taste is predominant. The

term distilled gin also applies to mixtures of distilled

gin and similar alcohol of agricultural origin. Natural

and/or nature identical substances may also be used.

London gin is a type of distilled gin (and not a geo-

graphical location of manufacture), whereas Ply-

mouth gin is a geographical designation. Gin simply

made by adding essences or flavorings to alcohol may

not be called distilled gin – this product is known in the

industry as a compounded gin. The minimum bottling

strength for all gin is 37.5% vol.

0010The regulations of other countries reflect much of

the European law. The United States Bureau of Alco-

hol, Tobacco and Firearms distilled gin definition

requires all the alcohol to be distilled with the botan-

ical materials and the minimum bottling strength to

be 40% vol. (80



US proof). Canada also has a 40%

minimum bottling strength, whereas in Australia, it

is 37% vol.

Materials for Gin Distillation

0011The three key ingredients for gin distillation are

botanical materials, alcohol, and water. Each gin

distiller has a specific botanical recipe for each

brand and will have exacting quality requirements.

fig0001 Figure 1 (see color plate 78) Juniper berries, the essential botanical ingredient in gin, together with commonly used coriander

seeds.

2890 GIN/The Product and its Manufacture

0012 Gin botanical ingredients are subject to rigorous

quality assessment before purchase, are often stored

for 2 years before use, and are carefully blended to

ensure minimal seasonal and batch to batch variation.

The essential ingredients are juniper berries (Juniperus

communis). Although juniper is dispersed widely, it is

usually harvested for distilling in Italy and the Balkans.

Coriander seeds (Coriandrum sativum) are sourced

from Morocco and Russia, angelica root (Archangelica

officinalis) from Germany, and orange and lemon peels

from Mediterranean countries. Drawings of juniper

and coriander are shown in Figure 1. Other botanical

materials used in the recipes of specific gins include

aniseed, calamus root, caraway seed, cassia bark, car-

damom seeds, cinnamon, fennel seed, liquorice root,

nutmeg, orris root, and herbs.

0013 The alcohol used for gin distilling is known as

neutral alcohol. It is of agricultural origin and is

commonly fermented from cereals or molasses. Gin

distilled from grain neutral spirits is often sold at a

premium. Neutral alcohol is produced on continuous

distillation columns and is highly rectified. The

resulting distillate is essentially very pure ethanol

with only very small traces of congeners (that

is, other compounds from the fermentation). The

characteristics of ethyl alcohol of agricultural origin

are defined within Annex 1 of regulation 1576/89,

and the minimum alcoholic strength after final recti-

fication is 96% vol. Production of the neutral alcohol

is a separate process from gin distilling and is often

conducted at separate distilleries and by different

producers.

0014Water is used in two stages of gin production. First,

it is added to the neutral alcohol in the still prior to

the start of distillation, and second, it is added to the

distillate in order to bring the gin distillate down to

the required bottling strength. In both cases, high-

purity water is required. It must be clear, odorless,

and low in trace dissolved minerals. It is common for

such water to be taken from a local supply and puri-

fied by demineralization and carbon treatment pro-

cesses. Historically, many of the London gin

distilleries were sited where wells could provide

good sources of water.

Gin Distillation

0015Distilled gin is produced in a batch process in a trad-

itional copper still similar to those used for Scotch

malt whisky. Figure 2 shows a schematic diagram of

Head cooling

water

Alcohol and water

addition

Botanicals added through

manway door

Heating jacket

Spent materials

Out

Heads Gin Tails

Spirit safe

Out

Condenser

cooling

water

Steam supply to heating coil

Vapour

Out

fig0002 Figure 2 Schematic diagram of a typical gin still.

GIN/The Product and its Manufacture 2891

the process, and Figure 3 shows a photograph of the

modern Tanqueray Gordon distillery equipped with

old traditional gin stills.

0016 The start of the distillation process involves

charging the still with water followed by neutral alco-

hol in order to achieve an alcoholic strength around

60% vol. Botanical ingredients are then added into

the still, either loose or in a bag suspended above the

liquid. The still is closed, and heat is applied, now-

adays using a steam coil. As the liquid starts to boil,

the alcoholic strength of the distillate is greatest

and contains the most volatile botanical congeners

(mainly monoterpenes). This first fraction is known

as ‘heads’ and is kept separate, as it is not required.

The second fraction is the main product and is col-

lected as distilled gin at around 80% vol. alcoholic

strength. This fraction contains all the congeners

found in gin, including monoterpenes, terpineols,

and sesquiterpenes). Lastly, as the alcohol content of

the distillate starts to fall, the temperature increases,

fig0003 Figure 3 Modern Tanqueray Gordon distillery equipped with old traditional gin stills.

2892 GIN/The Product and its Manufacture

and the character of the distillate changes as the less

desirable low volatile congeners begin to boil. The

third ‘tails’ fraction is then collected separately with

extra heat applied to the still to recover as much

alcohol as possible. The heads and tails fractions are

combined as feints and subject to a separate alcohol

recovery process.

0017 Throughout the process, the gin distiller will care-

fully control the rate of heating, monitor the alcoholic

strength of the distillate and check the sensory prop-

erties of the gin. The gin distillate may then be simply

diluted with water down to bottling strength (to

produce a ‘one shot’ gin) or may be blended with

other distillates and alcohol to produce the final

distilled gin.

0018 Lastly, compounded gin may be made by adding

gin essences or flavoring to alcohol. This is the sim-

plest way of making a cheaper product. The essences

are normally made by a specialist flavor company

according to a defined recipe. No further processing

is required except reduction to bottling strength. Such

products may not be called distilled gin.

Packaging and Distribution

0019 Immediately before bottling, gin is reduced with

water to the required bottling strength and passed

through a fine filter. Final alcoholic strengths com-

monly range from a minimum of 37.5 and 40% in

domestic markets up to 47.3% vol. in duty free shops.

Gin is normally packaged in glass or PET (polyethyl-

ene terephthalate) plastic bottles in common with

other popular distilled spirits. The most popular

bottle sizes are 700 ml, 750 ml, and 1 l. Fifty-milliliter

PET bottles are common in the airline trade. Gin is

often distilled at one site and packaged at another.

Many brands are shipped overseas at high alcoholic

distillation strength in stainless steel tanks for local

bottling in order to achieve import tax and transport

cost savings by using locally sourced packaging. Gin

is a very stable product undergoing no degradation

when stored under good conditions in a properly

sealed bottle.

Flavored Gins

0020 A range of specialty products are based upon gin and

are made by both commercial and cottage industries.

Sloe gin is traditionally made by steeping sloe berries

(Prunus spinosa) in gin in order to extract its natural

flavors and juices from the fruit. Similarly, orange and

lemon gins are made by steeping the peels of these

fruits in gin. After a number of weeks, the steeps are

filtered, sweetened to taste with sugar, and reduced in

alcoholic strength with water ready for bottling.

Ingredient variations on these processes include the

use of fruit juices and flavorings.

Gin Today

0021Gin is one of the major international generic distilled

spirits with only vodka and Scotch whisky selling

greater volumes. Table 1 lists the major eight gin

brands in the year 2000.

0022In addition, there are a large number of other local

brands to be found plus many own-label brands pro-

duced for sale in supermarkets. The more expensive

brands tend to be distilled gins, and the cheapest

brands are often made using compounding processes.

0023As with most distilled spirits, many rival products

seek to imitate the leading brands. Analytical

methods have been developed by which the authenti-

city of suspect samples may be checked, thus helping

protect the interests of the consumer and brand

owner.

See also: Alcohol: Properties and Determination;

Metabolism, Beneficial Effects, and Toxicology; Alcohol

Consumption; Legislation: History

Further Reading

Aylott RI (1995a) Flavoured spirits. In: Lea AGH and Pig-

gott JR (eds) Fermented Beverage Production, p. 275.

Glasgow: Blackie Academic & Professional.

Aylott RI (1995b) Analytical strategies to confirm gin au-

thenticity. Journal of the Association of Public Analysts

31: 179.

Clutton DW (1979) The Production of Gin and Vodka.

Brewers Guardian 108(10): 25.

Coates G (2000) Classic Gin. London: Prion Books.

European Communities (1989) Council Regulation 1576/

89 laying down general rules on the definition, descrip-

tion and presentation of spirit drinks. Official Journal of

the European Communities L:160/1.

Simpson AC (1977) Gin and vodka. In: Rose AH (ed.)

Alcoholic Beverages, p. 537. London: Academic Press.

tbl0001Table 1 Major eight gin brands, their key markets, and sales in

2000

Brand Region Sales

(millions of 9 liter cases)

Ginebra San Miguel Philippines 27.3

Gordon’s gin International 5.05

Seagram’s gin USA 3.42

Gilbey’s International 2.25

Beefeater International 2.20

Larios gin Spain 2.15

Tanqueray gin International 1.83

Bombay Sapphire gin International 1.82

From: Drinks International 2001, The Club 2000.

GIN/The Product and its Manufacture 2893

Composition and Analysis

E Guerra Herna

ndez, Universidad de Granada,

Granada, Spain

Introduction

0001 Gin is a colorless spirit obtained by distilling an aqueous

mixture of alcohol together with aromatic plant mater-

ials, generally juniper berries (Juniperus communis L.),

to which water and alcohol and at times fruit juices,

extracts, and/or essential oils of fruits may be added.

According to this definition there are more than 10

different types of gins on the market, produced in vari-

ous parts of the world. The components of gin are water,

alcohol, and compounds derived from the plant mater-

ials, essential oils and fruits used in its production.

Composition

Alcohol

0002 The carbohydrate source for obtaining alcohol by

fermentation is a grain mash consisting of corn,

malt, and rye in varying proportions according to

the country of production. Alcohol obtained in this

way is purified by distillation to eliminate the flavor

of the fermentation products until a clear, clean,

and neutral alcohol in taste and odor is obtained.

Following this procedure, only minor traces of alde-

hydes, esters, and higher alcohols are found in the

majority of gins, with the exception of Dutch gin,

which is made from unrefined alcohol.

Plant Ingredients

0003 The main plant ingredients used are juniper berries

together with coriander seeds and angelica root. The

precise proportion in which the distilleries use these

three components in combination with other plant

ingredients, such as anise seed, bitter orange peel,

cinnamon bark and cassia bark, is a secret of the

distillery, since this is what determines the distinctive

taste of each gin.

0004 The essential oil of these ingredients gives gin

its characteristic flavor and is obtained by distilling

alcohol together with the particular plant ingredients

(distilled gin) or, if the essential oil is already in liquid

oil form, it is added to the alcohol, as in the case of

compound gin.

0005 This essential oil contains terpenes (a-pinene,

myrcene, limonene, g-terpinene, linalool, terpine-

4-ol, geraniol, borneol) and their proportion varies

according to the combination in which the plant

materials are used.

0006In summary, all types of gin contain, as main com-

ponents, ethyl alcohol (38–50% alcohol by volume)

and water, and in smaller quantities terpenic com-

pounds, which are precisely those which define it

and distinguish it from any other alcoholic beverage.

Only a few gins contain sucrose, and in others

esters, aldehydes, and higher alcohols are found in

appreciable concentrations.

Flavor Components

0007The most common gin is the London type in which

the flavor components are derived from the plant

ingredients used in its production. A distilled dry gin

is a distilled gin with a very small proportion of plant-

derived components.

0008The two main plant ingredients are J. communis L.

berries and Coriandrum sativum L. seeds. The main

components of essential oil from these plants are

terpenes which constitute the major part of the flavor

of the gin. The components found in these plants and

in the gins made from them are given in Table 1.

0009As can be observed, the main terpenic components

of the gin, a-pinene and linalool, coincide with

those of its plant ingredients. If only the heart

of the distilled fraction is used, the proportion of

the main components with low molecular weight

(unoxygenated monoterpenes) from J. communis L.

is reduced.

0010Some gins use not only these components but also

other plant ingredients which contain a high propor-

tion of essential oil and, in addition, possess a terpene

content near to or exceeding 50%. Their effect,

although they are only used in small proportions to

give the gin aroma, can significantly affect the final

aroma. This is the case with the use of orange oil,

which contains 90% d-limonene, and cinnamon and

cassia bark, whose oils contain 70–95% and 60–70%

cinnamic aldehyde respectively.

tbl0001Table 1 Range of main terpene components (expressed as

relative percentage) in berries of Juniperus communis L. and

seeds of Coriandrum sativum L., and main terpenes found in

samples of gin

J. communis C. sativum Gin

a-Pinene 30–35 Linalool 65–75 Linalool

b-Myrcene 18–30 p-Cymol 5–7 a-Pinene

b-Pinene 2–14 Borneol 0.2–7 Sabinene

Limonene 4–10 a-Pinene 2.5–6.5 b-Myrcene

Terpinen-4-ol 0.1–10.5 g-Terpinene 1.4–10 Limonene

Terpinolene 0.5–3 Geraniol 2–4 g-Murolene

g-Murolene 1–4.3 b-Pinene 0.3–1.4 Terpinen-4-ol

Sabinene 0.2–3 Limonene 0.1–1.7 Geraniol

g-Cadinene 0.4–1.6 Camphene 0.4–0.8 g-Terpinene

p-Cymene 0.1–1.5 Sabinene 0.1–0.2 a-Terpinene

2894 GIN/Composition and Analysis

0011 The odor threshold for linalool (a major compon-

ent of coriander oil) in 20% ethanol is 9 p.p.m., while

for g-terpinene it is 1.5 p.p.m.; as both have an

‘orangey’ aroma, the latter compound can be more

dominant than linalool in the aroma.

0012 The main component of juniper (a-pinene, thresh-

old value 5 p.p.m.) seems to play a decisive role in

the aroma, which is not the case for p-terpineol

(threshold value 13 p.p.m.).

0013 Limonene, although having a high odor threshold

(6.5 p.p.m.), contributes decisively to the flavor of

‘orangey’ gins which are made with oranges and

lemons. However, this is not the case with cinnamal-

dehyde (the major component of cassia and cinnamon

bark), which is normally found in gins at concentra-

tions below its odor threshold (3 p.p.m.).

0014 In Dutch gin, together with the terpene hydro-

carbons, the components responsible for the flavor

include higher alcohols, especially isomyl alcohol

and, to a lesser degree, isobutanol, propanol, ethyl

acetate, and 2-butanol.

Effects of Storage

0015 Gin does not age and it does not require a period after

production to reach maturity. On the contrary, since

the aromatic components of the gin are essential oils

which tend to oxidize and produce the so-called ter-

pene-like character, it is best to consume the products

as soon as possible. Terpenes may also be lost owing

to their high volatility.

Analytical Methods (Authentication)

0016 The following factors determine the flavour of

bottled gin: quality of initial alcohol, formulation of

plant ingredients, and distillation technique. Control

of the distillation technique (steam pressure, water

flow, etc.) is automated in the majority of distilleries.

0017 Analysis of the alcohol is usually restricted to the

determination of extract, acidity, esters, aldehydes,

methanol, higher alcohols, nitrogenated bases and

furfural, analyses which can be performed using trad-

itional chemical methods. For example, the extract is

determined by weighing the samples after evapor-

ation to dryness. The total acidity is determined by

neutralization with a standard alkaline solution.

Esters (expressed as ethyl acetate) are quantitated by

reaction with alkaline hydroxylamine to form a

hydroxamic acid which, after acidification, forms

a colored complex with ferric ions. Ester concentra-

tion is proportional to absorbance at 525 nm at con-

stant alcohol concentrations. Aldehydes (expressed

as acetaldehyde) are quantitated with an excess of

sodium bisulfite, addition of iodine and analysis of

remaining iodine with sodium thiosulfate. Methanol

is determined by measuring the absorbance at 575 nm

after the addition of potassium permanganate and

chromotropic acid to a sample, previously diluted at

constant alcohol concentration. Higher alcohols

(fusel oil) are determined by means of the formation

of colored derivatives with p-dimethylaminobenzal-

dehyde, which are measured at 538–543 nm, or with

the sodium salt of 4-hydroxybenzaldehyde sulfonic

acid, which is then measured at 445 nm. The content

in nitrogenated bases is based on fixing them using

phosphoric acid followed by an initial distillation.

The bases are liberated with sodium hydroxide and

a second distillation is performed. The second distil-

late is tested with hydrochloric acid. The presence of

furfural is detected by the reddish color that appears

when this compound reacts with aniline in acetic

medium.

0018These methods are acceptable if there are high

levels of the compounds in question, but are not as

useful when the levels are very low, in which case it is

recommended that the analysis be carried out by gas

chromotography using polar columns (Carbowax

1500) under isothermal conditions with flame ioniza-

tion detection. This allows not only detection of com-

ponents at very low levels but also individual

concentration of each component. With this method

aceltaldehyde, ethyl acetate, methanol, and higher

alcohols can be determined simultaneously.

0019When the quantities of the above compounds are

high, the alcohol must be purified before it is used in

the production of gin.

0020Analysis of the plant components is normally

carried out for juniper berries, coriander seeds, and

angelica root. Any other plant components are dis-

tilled and compared by taste with accepted standards.

0021A quality essential oil made from juniper must have

a refractive index between 1.4840 and 1.4870; lower

levels are indicative of a high content of low-boiling

terpenes, which are undesirable in the production of

gin. The refractive index for coriander seed oil must

be between 1.463 and 1.471 and for angelica root

between 1.476 and 1.488.

0022Measurement of the ultraviolet absorption spectra

of these oils also provides quick and useful data with

regards to the quality of the oils. Thus, juniper oil

absorbs strongly between 220 and 240 nm, coincid-

ing with the absorption of one of its components,

terpine-4-ol, while coriander oil begins to absorb at

lower wavelengths between 200 and 225 nm. Dilu-

tions of these essential oils in alcohol are compared by

taste with a sample standard and, according to the

aromatic level required in the final gin, the appropri-

ate plant components are mixed well before proceed-

ing with the distillation stage.

GIN/Composition and Analysis 2895

Sensory Analysis

0023 Quality control in large distilleries is carried out

by taste panels of 20–30 members. These people

examine similar samples in difference tests (triangular

test). This panel is used both to insure uniformity of

the gin which comes to the market as well as for

examining the initial alcohol and the solutions of

essential oil extracted from the plant ingredients.

0024 To control the quality and authenticity of a gin that

is produced, a sensorial analysis, by means of a taste

panel, is used. This provides a profile of the taste and

character of the gin. According to these analyses

various gins can be identified, e.g., those with a taste

derived from juniper berries, and gins with a faint

orange taste which corresponds to those gins that

contain coriander oil; if the orange taste is strong,

this indicates that it contains other ingredients

which provide limonene. Finally, those flavors are

labeled ‘tails’ that correspond to samples which con-

tain other components such as those containing

cinnamaldehyde. When gins are produced with high

levels of cassia or cinnamon, or the samples similar to

Dutch gin, their aroma is derived not only from the

plant components but also from the initial alcohol,

which gives it an aroma similar to that of whisky.

Chemical Analysis

0025 The main ingredient together with water is ethyl

alcohol, which can be determined, after distillation,

by density measurement with a hydrometer.

0026 The content of extract, total acidity, aldehydes,

esters, nitrogenated bases, and furfural can be

analyzed by the traditional methods mentioned

early. The methanol and higher alcohols (2-butanol,

1-propanol, 2-methyl-1-propanol, 1-butanol, 2-methyl-

1-butanol and 3-methyl-1-butanol) are quantified by

means of chromatography in Carbowax 1500 column

and with 4-methyl-2-pentanol as internal standard.

(See Chromatography: Gas Chomatography.)

0027 Analysis of reducing sugar is done by the reducing

properties of the sample, previously clarified, in a

cuproalkaline solution. The technique is also applic-

able to sucrose analysis. The sample content is estab-

lished by the difference in the reducing capacity

before and after inversion with hydrochloric acid.

(See Carbohydrates: Classification and Properties.)

0028 Heavy metals As, Pb, Zn, and Cu, are determined

by atomic absorption spectrophotometry. (See Spec-

troscopy: Atomic Emission and Absorption.)

0029 Analysis of compounds from the plant ingredients

which give the gin its character is mainly by ultravio-

let spectroscopy and gas chromotography. Ultraviolet

spectroscopy is used to characterize gin in the same

way as for the analysis of the plant ingredients;

analysis between 220 and 240 nm gives information

about the level of juniper oil in the gin when com-

pared with diluted essential oil in alcohol of the same

proof. Measurements between 200 and 225 nm give

the level found in coriander oil. The results obtained

provide a partial indication of ‘total flavor level’ as

‘juniper’ or ‘coriander’ because the oils used for

standardization are steam-distilled products, whereas

gin is distilled in ethanol and part of the terpene

components of plants is rejected as ‘feints’ (combined

heads and tails).

0030Moreover, this type of analysis has other disadvan-

tages. The first is that it gives only a general idea of

the flavor but no information as to the identity of the

components. It does not allow a distinction to be

made between gins which contain orange and corian-

der oil from those that only contain the latter, since

both absorb at the same wavelength. Finally, this

method is only applicable to gins whose initial alco-

hol has been purified, or else the aldehydes, esters,

and higher alcohols that may be present will interfere

with the spectrophotometric measurements.

0031The chromatographic method offers the advantage

of identifying individual volatile components of the

gin but the disadvantage is that the sample must be

concentrated, owing to the low levels of the compon-

ents, with the risk of obtaining results which may not

be accurate since the proportion of the components

obtained in the concentrate may not be the same as in

the initial sample. There is also a risk of introducing

artifacts. Furthermore, the increased time required for

the analysis and material waste must be considered.

0032The two most important techniques for concentra-

tion of the volatile components in alcoholic beverages

are liquid–liquid extraction and methods based on

absorption–desorption. Both procedures have been

used on gin. It has also been found that the best solv-

ents are dichloromethane, trichlorotrifluorethane,

and a 1:1 mixture of these. The results were reprodu-

cible after an extraction time of 5 h and 50 ml of

solvent was used to extract 100 ml of the sample; the

concentration factor obtained was 20 and the yields

were 80% for monoterpenes and 100% for oxygen-

ated monoterpenes. In order to obtain higher concen-

tration factors, continuous extraction methods may

be used. For studying concentration through absorp-

tion–desorption, charcoal columns have been used.

0033These two methods have been applied to the analy-

sis of samples of commercial gin using dichloro-

methane as a solvent for the concentration with an

orbital shaker and trichlorofluoromethane for con-

centration using continuous extraction. The extracts

were analyzed by gas chromatography, using a

packed polar column (Carbowax 20M). The number

2896 GIN/Composition and Analysis

of compounds clearly identified was six with the first

procedure and more than 20 with the second, with

the latter having the advantage that the extract, once

constituted, was identical to the initial sample, from a

sensory point of view.

0034 Discontinuous liquid–liquid extraction for the

quantitative analysis of volatile components has also

been used. The solvent was diethyl ether (200 ml) and

was concentrated to a final volume of the extract of

6 ml. The volume of the initial sample was 60 ml and

the column utilized was polar (Carbowax 20M), but

in this case using a capillary column of 50 m length.

0035 Quantification was carried out by dissolving the

terpenes in 40% alcohol by volume at different

concentrations and using the same method as with

the gin, thereby obtaining standard curves for each

component.

0036 In this study 21 different terpene components

were quantified (a-pinene, b-pinene, sabinene, d-3-

carene, b-myrcene, limonene, 1,8-cineole, g-terpiene,

p-cymene, a-terpinolene, camphor, linalool, linalyl

acetate, bornyl acetate, isobornyl acetate, caryophyl-

lene, terpinen-4-ol, myrtenyl acetate, a-terpineol,

geranyl acetate, geraniol). Figure 1 shows a chro-

matogram obtained by this method.

0037 Themaincomponentsidentifiedweresimilarto

those obtained in other studies, and were (Table 1)

linalool, a-pinene, b-myrcene, limonene, terpinen-4-ol

and geraniol, with the exception of g-murolene, a

component not found in gins analyzed, but which was

detected in the juniper berries in an appreciable

quantity and which could have been an indicator of

the quality of the gin.

0038In summary, the only components identified in gin,

together with alcohol and water, are the terpenes and

these, when found at low levels, require concentra-

tion prior to analysis. For the determination of indi-

vidual compounds a gas chromotographic analysis

with high-resolution columns is necessary due to the

structural similarity of the terpenes.

0039Together with these components, the Dutch gins

contain higher alcohols (propanol, isobutanol, and

isoamy alcohol) in such concentrations (70–

90 mg l

1

,70–115 mg l

1

, and 315–320 mg l

1

re-

spectively) that it is possible to determine them

directly in the sample by gas chromotography.

0040The use of terpenic compounds permits differenti-

ation between gin brands by applying several multi-

variate statistical methods (principal component;

linear, quadratic and nearest neighbor discriminant;

cluster analysis and outlier detection). The distilleries

reproduce the process of elaboration of gin to obtain

uniform terpenic coumpounds and flavor gin.

0041The chemical components of the gin for which

limits have been established, because they reduce the

quality of the gin or because they may be toxic are

acidity, which must not exceed 10 mg l

1

, expressed

as acetic acid; methanol, which must not exceed

010203040506070

Time (min)

fig0001 Figure 1 Chromatogram of terpene components found in a sample of commercial gin: (1) a-pinene; (2) b-pinene; (3) b-myrcene; (4)

limonene; (5) g-terpinene; (6) p-cymene; (7) a-terpinolene; (8) methyl caprylate (internal standard); (9) camphor; (10) linalool; (11)

linalyl acetate; (12) bornyl acetate; (13) isobornyl acetate; (14) caryophyllene; (15) terpinen-4-ol; (16) myrtenyl acetate; (17) a-terpineol;

(18) geranyl acetate; (19) geraniol.

GIN/Composition and Analysis 2897