VanJaarsveldF.WW0907 Final Report - SAWIS library · A study of the influence of processing factors such as distillation and ageing on isotopic ... Several publications are in progress

WW 09/07 – Dr. F.P. van Jaarsveld

CFPA Canning Fruit Producers’ Assoc.

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PO Box 426 Paarl, 7620

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Submit to: Louise Kotzé

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DFTS Dried Fruit Technical Services

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FINAL REPORTFINAL REPORTFINAL REPORTFINAL REPORT

FOR FOR FOR FOR 2002002002006/76/76/76/7

PROGRAMME & PROJECT LEADER INFORMATION

Programme leader Project leader Title, initials, surname Dr. O. P. H. Augustyn Dr. F. P. van Jaarsveld

Present position Research leader Senior Researcher Address Private Bag X5026

Stellenbosch 7599

Private Bag X5026 Stellenbosch 7599

Tel. / Cell no. (021) 809 3010 (021) 809 3052 Fax (021) 809 1400 (021) 809 3002

E-mail [email protected] [email protected]

PROJECT INFORMATION

Project number WW 09/07

Project title Proof of authenticity of South African brandy

CFPA DFPT DFTS Winetech Brandy and Distillation Technology

Industry programme

Other Fruit kind(s) Grapes

Start date (dd/mm/yyyy) 01/04/2000 End date (dd/mm/yyyy) 31/03/2007


FINAL SUMMARY OF RESEARCH PROJECTFINAL SUMMARY OF RESEARCH PROJECTFINAL SUMMARY OF RESEARCH PROJECTFINAL SUMMARY OF RESEARCH PROJECT

PROGRAMME & PROJECT LEADER INFORMATION

Programme leader Project leader Title, initials, surname Dr. O. P. H. Augustyn Dr. F. P. van Jaarsveld Institution ARC Infruitec-Nietvoorbij ARC Infruitec-Nietvoorbij Tel. / Cell no. (021) 809 3010 (021) 809 3052

E-mail [email protected] [email protected]

PROJECT INFORMATION

Project number WW 09/07

Project title Proof of authenticity of South African brandy

Fruit kind(s) Grapes

Start date (dd/mm/yyyy) 01/04/2000 End date (dd/mm/yyyy) 31/03/2007

The main aim of this project is to create a database of isotopic ratios [(D/H)I, (D/H)II,

δ13C and δ

18O] for authentic and commercial brandy samples against which all South

African brandies can be compared in the future to determine whether or not the brandy

has been adulterated with other botanical or synthetic sources of ethanol.

δ13C-IRMS proved to be the best method for detection of the addition of spirits from C4

plant (i.e. cane and corn) and synthetic (i.e. SASOL) sources to brandy, with detection

limits ranging between 0 and 5% with respect to the unadulterated commercial

brandies. Ethanol (D/H)I-SNIF-NMR also proved to be effective for the detection of

addition of synthetic spirits (i.e. SASOL) to brandy. Commercial brandies, using the

authentic database constructed over five years, proved to be adulterated up to a 100%

with one or more sources of foreign ethanol.

A study of the influence of processing factors such as distillation and ageing on isotopic

fractionation, showed significant (p < 0.05) fractionation of (D/H)I during the second pot-

still distillation. Column-still distillation brought about significant fractionation of all

isotopic parameters, except (D/H)II. Generally, significant (p < 0.05) enrichment for all

three natural isotopes, i.e. (D/H)I, (D/H)II and δ13C‰ was observed over a three year

storage period.


An authoratative database of deuterium/ hydrogen (D/H) and carbon-13/12 ratios for the

ethanol in authentic South African brandies, including all variations caused by grape

cultivar, geographic location, still design and vintage, has been compiled over five

years. Checking the correctness and accuracy of five years’ worth of data and

information, entered manually into the system by various data capturers, however,

prove to be a major task and is nearing completeness.

All main objectives of project WW 09/07 have been attained. Based on the fact that

ageing in wooden casks for thirty six months leads to isotopic fractionation, a decision

regarding the inclusiveness of all analysed ageing samples in the database must be

made. Based on the fact that distillation does bring about isotopic fractionation in some

cases, a decision will have to be made as to whether or not brandy base, distilling and

low wines should be excluded from the authentic database, the authentic database thus

being representative of only the final distillates, i.e. pot-still brandy and neutral wine

spirits. The database currently provides for the inclusion of all the components. If it is

decided to exclude the brandy base, distilling and low wines, minor structural/

programming/ visual basic changes/ corrections of the database will have to be made.

The isotopic brandy database is in Microsoft Access format and can be uploaded onto a

network for use by one or multiple authorised users with the necessary access and

passwords. Typically, unknown or suspicious commercial brandies and/or crude spirits

imports will be analysed isotopically with SNIF-NMR and IRMS by accredited

laboratories, and the results compared to the authentic and/or unadulterated

commercial databases. Samples clearly adulterated with one or more sources of non-

grape spirits, and more than two standard deviations out of spec as compared to the

authentic and unadulterated commercial samples, will be reported to be adulterated with

one or more adulterants. A report, with average, minimum, maximum, upper & lower

limits, and number of samples, is generated by the database. This report can then be

attached to a report on the unknown sample. The report on the unknown sample states

various details about the sample and allows for calculation of the percentage

adulteration and comments regarding its authenticity. Graphical representations allow

the sample(s) to be screened visually for any obvious adulteration(s).

Several publications are in progress and will follow this final report.

Final report 4


FINAL REPORT

1. Problem identification and objectives State the problem being addressed and the ultimate aim of the project.

The global wine and spirits markets have expanded rapidly over the last 10 years

or so with the increased accession of the New/Third World and Eastern European

countries (old east-block countries) into the free and traditionally more West

European markets. This has also brought about increased awareness of the

authenticity of wine and spirit products. Wine and spirit forgery is indeed becoming a

very tempting criminal activity. Forgery has been very difficult to detect, let alone

prove beyond reasonable doubt in a court of law, but science is coming to the

rescue. Today, many European countries, as well as the USA, have mechanisms in

place to test for the authenticity of these beverages. In the future European Union

regulations may require full authentication of imported wines and spirits before sale.

Certification of authenticity, like certification of origin, will thus be highly likely in the

future. It would be beneficial to the industry if South Africa can supply information

about the authenticity of its wines and spirits if and when this type of information is

requested.

South Africa, like other countries globally, is also exposed to various forms of

adulteration of its products, such as the addition of non-grape and synthetic forms of

alcohol to brandy. By law, South African brandy can only be made from grapes and

must be made from potstill brandy and wine spirits, blended in a 30/70% ratio. More

and more "brandies" are sold at prices that make it clear that these brandies could

not have been made according to standard, legal practices. To protect the Brandy

Industry, the consumer and the State’s income from excise, it has become very

important to establish a national isotopic databank with which to prove the

authenticity of South African brandy. The main purpose of this study is to determine

the natural hydrogen and carbon isotope content of the ethanol in South African

brandy, and to use these data to construct a database against which the authenticity

of SA brandy can be verified.

Objectives for the current year (2006/07):

Final report 5


• Decision regarding the inclusiveness of all analysed ageing samples in the

database must be made, and based on the outcome might have to be

included.

• Decide whether or not brandy base, distilling and low wines should be

excluded from the authentic database with possible minor

structural/programming/visual basic changes/corrections of the database.

• Publication of research results.

2. Workplan (materials & methods) List trial sites, treatments, experimental layout and statistical detail, sampling detail, cold storage and

examination stages and parameters.

Documentation

Documentation accompanied the sampling bottles delivered to producers. The

documentation included a sampling procedure, drivers log, description sheet and

written report. Producers had to complete the documentation/forms and return it with

the samples to the ARC Infruitec-Nietvoorbij.

Distillation and sampling

Brandy base and distilling wines, sourced in from various suppliers representing

different wine producing regions, of which the vintage year, grape production area

and in some cases the variety were known, were kept and distilled separately at the

various distilleries from producers using traditional column- and pot-still equipment.

Brandy base- and distilling wines, together with corresponding distillates, i.e. low

wine, unmatured pot-still brandy, neutral wine spirits and/or crude spirits, were

sampled and analysed for their isotopic ratios, i.e. (D/H)I, (D/H)II and δ13C of ethanol

and δ18O of wine water. Results were taken up as representative of the authentic

dataset in the isotopic databank at the institute.

Commercial brandies, imported spirits and other non-grape spirit sources

In addition to brandy base wine, distilling wine, low wine, potstill brandy and neutral

wine spirits, foreign/imported grape spirits, commercial brandies, adulterated

brandies and other botanical spirit sources were also sourced in. Commercial

brandies were obtained from various sources including reputable producers, official

Final report 6


regulatory bodies, The SA Brandy Foundation, members of the public and the Cape

Wine-& Spirits Institute. Non-grape spirit sources i.e. flavoured grain spirits, cane

spirits and synthetic alcohol, were obtained from reputable producers and was

accompanied by specification certificates and certificates of analysis. All samples

were analysed for their stable isotope ratios.

Ageing and sampling

Wines from three (Wellington Cooperative Cellar, Goree and Viljoensdrift Wines) and

six (Agterkliphoogte/Wandsbeck Wines, Badsberg Wine Cellar, De Doorns Winery,

De Wet Co-op Winery, Slanghoek Winery and Villiersdorp Cellar) suppliers were

distilled separately at selected premises (i.e. Worcester and Stellenbosch) and in

defined pot-stills of producers I and II, respectively. Resultant unmatured pot-still

brandies were aged in French oak casks in dry and humid, and dry stores of

producers I and II, respectively, under defined conditions. Samples were drawn

every six months from previously opened (during previous 6-month sampling periods)

and unopened vats over a period of three years and analysed for their isotopic ratios,

i.e. (D/H)I, (D/H)II and δ13C.

Purposeful adulteration of brandy

Brandy samples were serially adulterated with various non-grape sources of ethanol,

i.e. cane, grain (maize), synthetic (SASOL) and a mixture of these, respectively, and

analysed for their isotopic ratios, i.e. (D/H)I, (D/H)II and δ13C.

Chemical analysis

The site-specific quantitative analysis of deuterium at the methyl (D/HI) and

methylenic (D/HII) positions of ethanol was carried out at the Istituto Agrario di San

Michele all’Adige, Italy with an AMX 400 Bruker NMR instrument, in accordance with

the EC method (EC Regulation n° 2676/90) and with a line broadening of 0.5 Hz.

Results were expressed as parts per million (ppm). δ13C of ethanol and δ18O of wine

water were measured with IRMS (SIRA II VG mass spectrometer) according to the

Italian official method and EC Reg. N° 822/97. The results were expressed as ‰

scale against international standards PDB for carbon and V-SMOW for oxygen

isotopes. Analytical errors are within the range fixed by the quoted methods.

Final report 7


Statistical procedures

The variables measured were subjected to Analysis of Variance (ANOVA), using

GLM (General Linear Models) procedure of SAS statistical software version 8.2 (SAS

Institute Inc., Cary, NC, USA) (SAS, 2000). The Shapiro-Wilk test was performed to

test for normality (Shapiro, 1965). Fisher’s t-least significant difference (LSD) was

calculated at the 5% level to compare treatment means. A probability level of 5%

was considered significant for all significance tests.

3. Results and discussion State results obtained and list any benefits to the industry. Include a short discussion if applicable to your results. This final discussion must cover ALL accumulated results from the start of the project, but please limit it to essential

information.

Milestone Achievement

3.1. Effect of distillation on isotopic fractionation.

3.1. Objective completed.

3.2. Effect of ageing on isotopic fractionation.


3.3. Purposeful adulteration of unadulterated commercial brandy with non-grape sources of ethanol.


3.4. Detecting possible adulteration of commercial brandies with non-grape sources of ethanol.


3.5. Establishment of an authorative legal-technical isotopic database of deuterium/hydrogen (D/H) and carbon-13 ratios for the ethanol in authentic South African brandies, inclusive of all variations caused by grape cultivar, geographic location, still design and vintage.

3.5. Objective completed. Also see point 3.7 below.

3.6. Objectives not realised. 3.6. All main objectives realised.

3.7. Objectives completed. 3.7. All objectives completed. Minor aspects remaining and for consideration are:

• Based on the fact that ageing in wooden casks for 36 months leads to isotopic fractionation, decision regarding the inclusiveness of all analysed ageing samples (between 0 and 36 months) in the database must be made.

Final report 8


• Based on final results as compiled for this final report, and with regard to the above point, the database should probably be expanded to include more matured samples. The ageing experiment (272 samples) formed part of a separate experiment that looked at the effects of ageing on isotopic fractionation, the main thrust being the creation of the authentic database. Currently the strongest component of the authentic database is the unmatured samples received from industry. Representation of the matured component can be expanded during the necessary in-house upkeep/ maintenance of the database.

• Based on the fact that distillation does bring about isotopic fractionation in some cases, decisions will have to be made as to whether or not brandy base, distilling and low wines should be excluded from the authentic database. The database currently provides for the inclusion of these components. If it is decided to exclude these components, minor structural/ programming/ visual basic changes/ corrections of the database will have to be made.

• Should imports be considered part of the authentic dataset?

3.8. Future objectives. 3.8.

• Implementation and upkeep of the brandy isotopic database.

• Routine application of the database to investigate and prove possible adulteration of commercial brandies and brandy components.

• The ageing experiment (272 samples) formed part of a separate experiment that looked at the effects of ageing on isotopic fractionation. Based on the outcomes of the significant effects of ageing on isotopic fractionation, to incorporate a more representative number of matured pot-still brandy samples.

3.9. Publication of research results. 3.9. Several publications are in writing.

Final report 9


RESULTS

Milestone 3.1. Effect of distillation on isotopic fractionation

Since the sampling technique, such as distillation, could have an effect on isotopic

fractionation, wines were compared to their corresponding distillates to assess the

significance of the distillation procedure and equipment on isotopic fractionation.

Generally, using the Charentais method of double distillation in pot-stills, the first

distillation of brandy base (9-14 vol%) to low wine (±30 vol%) brought about little to

no (p > 0.05) isotopic fractionation, with only (D/H)I showing significant (p < 0.05)

fractionation (depletion or decreased values) during the second distillation of low

wine to pot-still brandy (±70 vol%) (Fig. 1A). Column-still distillation of distilling wine

(9-14 vol%) to neutral wine spirits (±96.6 vol%) brought about significant fractionation

of all isotopic parameters, except (D/H)II (Fig. 1B), with increases in (D/H)I (Fig. 1A)

and decreases in the δ13C (Fig. 1D) isotopic values.

a ab

b

a

b

104.5

105

105.5

106

106.5

107

107.5

Brandy base

wine

Low wine Pot-still brandy Distilling wine Neutral wine

spirit

Type of wine/spirit

(D/H

) I -

ppm

A

Final report 10


a

a a

a a

132

132.5

133

133.5

134

134.5

135

135.5

Brandy base

wine


spirit

Type of wine/spirit

(D/H

) II -

ppm

B

b

a

a a a

2.505

2.51

2.515

2.52

2.525

2.53

2.535

2.54

Brandy base

wine


spirit

Type of wine/spirit

R

C

Final report 11


a

b

a a a

-27.1

-27

-26.9

-26.8

-26.7

-26.6

-26.5

Brandy base

wine


spirit

Type of wine/spirit

13C

(‰

)

D

FIGURE 1 The effect of distillation on isotopic fractionation. Mean natural isotope ratios [A,

(D/H)I, B, (D/H)II; C, R and D, δ13C] of ethanol plotted as a function against type of wine/spirit. Brandy base and distilling wines were distilled in pot- and column-stills to low wine and pot-still brandy, and neutral wine spirits, respectively. Brandy base and distilling wines from suppliers/cellars situated in the various wine-growing regions of South Africa, were kept and distilled separately. The R parameter (graph C) is represented by the following equation: [(D/H)II/(D/H)I x 2]. Error bars represent the standard error of the mean. Treatments with the same letters do not differ significantly (p > 0.05). Milestone 3.2. Effect of storage on isotopic fractionation

Generally, significant (p < 0.05) enrichment for all three natural isotopes, i.e. (D/H)I,

(D/H)II and δ13C‰ was observed over the three year storage period (Fig. 2).

Differences, however, between neighbouring or consecutive ageing/sampling

periods, were generally smaller and insignificant. The low (D/H)II value at 24 months

ageing does not fit the trend, and is probably an outlier (Fig. 2B).

Opening and closing of wooden casks also impacted on isotopic behaviour of pot-still

brandy, although not always significantly.

Isotopic ratios of matured pot-still brandies from dry and humid ageing cellars were

not significantly different (p > 0.05). Store type, therefore, had no significant effect on

Final report 12


131

131.5

132

132.5

133

133.5

134

134.5

135

135.5

0 6 12 18 24 30 36

Ageing period (months)

(D/H

) II -

pp

m

B

105

105.5

106

106.5

107

107.5

108

0 6 12 18 24 30 36


(D/H

) I - p

pm

A

2.44

2.45

2.46

2.47

2.48

2.49

2.5

2.51

2.52

2.53

2.54

0 6 12 18 24 30 36


R

C

isotopic fractionation of any of the isotopic ratios studied, i.e. (D/H)I, (D/H)II and

δ13C‰ (Fig. 3).

-27

-26.8

-26.6

-26.4

-26.2

-26

-25.8

-25.6

0 6 12 18 24 30 36


δδ δδ1

3C

(‰

)

D

FIGURE 2

Mean natural isotope ratios [A, (D/H)I; B, (D/H)II; C, R and D, δ13C] of pot-still brandy, plotted as a function against ageing period for those vats opened once only during the three year storage period in wooden casks. The R parameter (graph C) is represented by the following equation: [(D/H)II/(D/H)I x 2]. Error bars represent the standard error of the mean. Polynomial trend lines are fitted to the data.

Milestone 3.3. Purposeful adulteration with non-grape sources of ethanol.

The serial adulteration of brandy with increased amounts of non-grape ethanol, i.e.

cane, grain (maize), synthetic (SASOL) and a mixture of these, respectively, were

performed in a first experiment (progress report 2004/5). In a second experiment,

smaller additions of cane spirits as adulterant were made in order to determine the

Final report 13


minimum amount that can be detected clearly and significantly. The results to the

second experiment are shown graphically in Figure 4.

FIGURE 3

Mean natural isotope ratios [A, (D/H)I; B, (D/H)II; C, R and D, δ13C] of pot-still brandy, plotted as a function against ageing cellar. Pot-still brandies were stored for three years in wooden casks in the two types of ageing cellars. The R parameter (graph C) is represented by the following equation: [(D/H)II/(D/H)I x 2]. Error bars represent the standard error of the mean.

The best method for the detection of adulteration of brandy (derived from the grape,

a C3 plant source) with foreign, non-grape spirits, including those of C4 plant origin

such as cane and maize, is δ13C-IRMS, with linear (R2 = 0.998 to 1) and significant (p

< 0.05) increases with increased adulteration (Fig. 4), and detection limits of >0% for

cane, 5% for grain, >0% for synthetic spirits and 2.5% for a mixture of these (Table

1). These detection limits are relevant specifically to the commercial brandy

adulterated and will deviate somewhat if the comprehensive dataset of the authentic

database was used. (D/H)I-NMR was effective in detecting additions of ethanol from

2.5235

2.524

2.5245

2.525

2.5255

2.526

2.5265

2.527

2.5275

2.528

Dry Humid

Type of ageing cellar

R

C

-26.35

-26.3

-26.25

-26.2

-26.15

-26.1

-26.05

-26

-25.95

Dry Humid


13C

(‰

)

D

106.6

106.7

106.8

106.9

107

107.1

107.2

Dry Humid


(D/H

) I -

ppm

A

134.7

134.8

134.9

135

135.1

135.2

135.3

Dry Humid


(D/H

) II - p

pm

B

Final report 14


synthetic origin (Table 1), with increased trends observed for (D/H)I with increased

additions of non-grape spirits (Fig. 4A). The parameter R, in contrast to (D/H)I,

decreased with increased adulteration with cane, grain and synthetic spirits, and

generally was more effective than (D/H)I for the detection of cane and maize spirits

additions to brandy (Table 1).

deff

defdef

de

ef

ded

c

baba

R2 = 0.968

105

106

107

108

109

110

111

112

113

114

0 20 40 60 80 100 120

% Brandy

(D/H

) I -

pp

m Deionised

Tap

Cane spirits

Rectified spirits

A

de

abc bcdbc bc

abcabcabcabcde

e

120

122

124

126

128

130

132

134

136

138

0 20 40 60 80 100 120

% Brandy

(D/H

) II -

pp

m Deionised

Tap

Cane spirits

Rectified spirits

B

Final report 15


ababcd

abc

abccdd

e

ff

g

R2 = 0.9877

R2 = 0.9742

2.36

2.38

2.4

2.42

2.44

2.46

2.48

2.5

2.52

2.54

2.56

0 20 40 60 80 100 120

% Brandy

R

Deionised

Tap

Cane spirits

Rectified spirits

C

a

c

de

f

ij

g

kh

bb

R2 = 0.9999

-28

-26

-24

-22

-20

-18

-16

-14

-12

-10

0 20 40 60 80 100 120

% Brandy

δ13C

(‰

)

Deionised

Tap

Experiment 1

Cane spirits

Rectified spirits

D

FIGURE 4

Effect of adulteration of brandy on the A, (D/H)I, B, (D/H)II, C, R and D, δ13C ratios of ethanol. The R parameter (graph C) is represented by the following equation: [(D/H)II/(D/H)I x 2]. Commercial brandy was adulterated with neutral potable cane spirits to different final concentrations at 43% alcohol made to volume with either deionised or tap water. % Brandy refers to the percent contribution of brandy to the alcohol content of the blend, the remainder being that of cane spirits. Neutral potable cane alcohol and rectified cane spirits were obtained from two separate producers, respectively. Treatments with the same letters do not differ significantly (p > 0.05) and were determined on the averaged values of deionised and tap water from experiment 2. In the second adulteration experiment (experiment 2) a more refined range of adulterations with less cane spirits were performed compared to experiment 1.

Final report 16


TABLE 1 Detection limits for potable and non-potable spirits types. Detection limit (%)1 Synthetic2 Cane3 Grain4 Mixed5 (D/H)I

6 Experiment 1 2.5 20 20 5 Experiment 2 - 10 - - (D/H)II

6 Experiment 1 20 20 20 10 Experiment 2 - 70 - - R7 Experiment 1 20 10 10 5 Experiment 2 - 10 - -

δ13C8 Experiment 1 >0 2.5 5 2.5

Experiment 2 - >0 - - 1Refers to the percent contribution of foreign non-grape spirit to the alcohol content of the blend, the remainder being that of brandy (refer to figure 3). 2Synthetic spirits from SASOL. 3Cane spirits from Illovu used in experiment 1 and neutral potable cane ethanol/spirits from Natal Chemical Products used in experiment 2. 4Flavoured grain/maize spirits from an animal food supplier and used in the production of whisky. 5A mixture of 1, 2 and 3. 6Determined using SNIF-NMR. 7The R-parameter (graph C) is represented by the following equation: [(D/H)II/(D/H)I x 2]. 8Determined using IRMS. Experiment 2 covered a more refined range of dilutions for cane spirits than experiment 1.

Milestone 3.4. Detecting possible adulteration of commercial brandies with non-

grape sources of ethanol.

A multi-isotopic approach using SNIF-NMR and IRMS, both official methods, could

effectively be used to detect illicit spirits and prove the authenticity of South African

brandies. Discrimination between C3 and C4 sources of ethanol, i.e. brandies as

opposed to cane or corn spirits, respectively, was possible, based on their (D/H)I and

δ13C‰ values, being higher in C4 plants (Fig. 5). Discrimination between ethanol

samples originating from plants with the same metabolism is also possible using

SNIF-NMR, with ethanol obtained from aerial plants (vine, apple tree, cereals) clearly

distinguishable from underground plants (i.e. potato and sugar-beet) (Fig. 5).

Ethanol derived from “questionable” or “suspicious” brandies proved to have been

adulterated to varying degrees with cane and corn spirits (Fig. 5). The commercial

brandies Oahill A442, Danté (no A number and sealed), Burnham A576 and

Burnham A576 have been adulterated to varying degrees with either cane/corn

spirits and/or synthetic spirits to varying degrees up to a 100% (Table 2). Boland VO,

Worcester VO, Burnwood VO, Kingsfield, Burnwood VO Superior, Kingsman VO, My

Kinda Old Cape Brandy, Magersfontein VO brandies, “suspicious” brandies received

from the SA Brandy Foundation, have all been adulterated to varying degrees with

Final report 17


cane/corn spirits (Table 2). Danté represents a unique and more complex case,

being adulterated with cane/corn spirits, and quite possibly also with synthetic spirits.

By considering brandies of known authenticity (or respective building block

components) and commercial brandies, in relation to other non-grape spirits or

ethanol sources, it is also possible to gain information about the origin of the ethanol

component of the spirits. Blended liquors, containing relative proportions of base

materials, show values in between single-source liquors. South African brandy

containing alcohol from any other source or raw material than grape, contravenes the

legislation as defined by law or standard practice. Uscrupulous practices of

chaptalisation or sugaring, refermentation and distillation of spoilt wines, and

purchasing or selling alcohol distilled from these poor quality wines, can be detected

using the analytical technology available. The delta values for all the “suspicious”

commercial brandies lie more than two standard deviations from the mean for

authentic spirits of the same type, representing a significant departure from the

normal reading for pure grape spirit, thus proving that these brandies have been

adulterated (Table 3).

TABLE 2 Calculation of the percent possible adulteration of commercial brandy with other non-grape sources of ethanol.

Commercial brandy Alcohol

(vol%)1

Adulteration5 (%) or percent added adulterant

δδδδ13C (D/H)I δδδδ

13C + (D/H)I Added C4

2 Synthetic

3 Added C4 +

synthetic4

Burnham - A573 43 0 0 0 Magersfontein VO Brandy – A443

43 10.88 -0.27 13.54

Danté VO Brandy – no A number

43 21.49 12.87 22.08

My Kind’a Old Cape Brandy – A360

43 29.73 5.25 30.13

Kingsman VO Brandy – A215

43 37.82 7.39 37.84

Kingsfield Brandy – A419 43 41.4 7.94 41.84 Oakhill Superior Brandy – A442

43 43.77 8.09 43.93

Burnwood VO Superior – A591/A637

43 39.63 6.73 40.47

Worcester VO Brandy – A353

43 47.14 6.45 49.92

Boland VO Brandy – A532 43 49.96 8.43 51.07

Final report 18


1Alcoholic strength of the commercial brandy. 2Calculated the possible addition of a C4 botanical source using a one-component-one-isotope approach. 3Calculation of the possible addition of synthetic ethanol using a one-component-one-isotope approach. 4Calculation of the possible adulteration with a C4 source and those of synthetic origin using a two-component-two-isotope approach. 5The adulteration is calculated relative to the alcoholic content of 43 vol% in %volume alcohol.

Final report 19


-30

-25

-20

-15

-10

-5

90 100 110 120 130 140 150

(D/H)I - ppm

13C

(‰

)

B-3-yr Rebate sp (import) B-5-yr Rebate sp (import) BC-10%CaneSpirit BC-10%Flav.GrainSpirit BC-10%Mix BC-10%Synthetic

BC-100%CaneSpirit BC-100%Flav.GrainSpirit BC-100%Mix BC-100%Synthetic BC-15%CaneSpirit BC-20%CaneSpirit

BC-20%Flav.GrainSpirit BC-20%Mix BC-20%Synthetic BC-30%CaneSpirit BC-4%CaneSpirit BC-40%CaneSpirit

BC-40%Flav.GrainSpirit BC-40%Mix BC-40%Synthetic BC-5%CaneSpirit BC-5%Flav.GrainSpirit BC-5%Synthetic

BC-60%CaneSpirit BC-60%Flav.GrainSpirit BC-60%Mix BC-60%Synthetic BC-8%CaneSpirit BC-80%CaneSpirit

BC-80%Flav.GrainSpirit BC-80%Mix BC-80%Synthetic BC-Boland VO BC-Burnham - A576 (seale) BC-Burnw ood V/O Superior

BC-Danté - no A-number (s BC-Kingsfield Brandy BC-Kingsman VO BC-KWV 10 BC-KWV 20 BC-KWV 3 Jaar

BC-KWV 5 Years BCMagersfontein VO Brandy BC-MyKind'aOldCapeBrandy BC-Napoleon Cortel VSOP BC-Oakhill - A442 (unsea) B-Crude spirits

B-Crude spirits (import) BC-Van Ryn's 10 Years BC-Van Ryn's 12 Years BC-Van Ryn's 15 Years BC-Van Ryn's 20 Years BC-Worcester VO Brandy

B-Distilling w ine BL-Grappa B-Low Wine B-Neutr Wine Spt (import) B-Neutral w ine B-Rebate spirits

B-Rebate w ine S-C4_Cane spirits SL-C3_(Sugar)beet SL-C3_Apple SL-C3_Apricot SL-C3_Grape

SL-C3_Straw berry SL-C4_(Sugar)cane SL-C4_Maize SL-Plum brandy/distillate SL-Synthetic S-Synthetic

Final report 20


FIGURE 5

Ethanol δ13C plotted as a function against ethanol (D/H)I for various botanical and synthetic sources of ethanol. Abbreviations: B, brandy; BC, commercial brandy; SL, spirits literature; S, authentic spirits. The abbreviations B and S represent authentic brandy (brandy base and distilling wines, low wine, pot-still brandy, crude spirits and neutral wine spirits) and non-grape spirits samples, collected, analysed, and/or accompanied by documentation with specifications. All brandy samples represented by the abbreviation B represent authentic South African wines, representative of local wine-growing regions, destined for brandy production and distillates, except for imports. TABLE 3 Consideration in relation to database of commercial brandies possibly adulterated. Type of brandy Average

of (D_H)I

Average

of δδδδ13C

StdDev of (D_H)I

StdDev

of δδδδ13C

Upper limit

Upper limit

Lower limit

Lower limit

Max of (D_H)I

Max of

δδδδ13C

Min of (D_H)I

Min of

δδδδ13C

Authentic brandy 106.19 -26.87 1.10 0.66 108.40 -25.55 103.98 -28.19 109.60 -24.83

102.41 -28.36

Burnham - A573 110.53 -26.39 Magersfontein VO Brandy – A443

105.95 -23.32

Danté VO Brandy – no A number

116.43 -19.86

My Kind’a Old Cape Brandy – A360

110.35 -17.17

Kingsman VO Brandy – A215 112.06 -14.53 Kingsfield Brandy – A419 112.50 -13.22 Oakhill Superior Brandy – A442

112.62 -12.59

Burnwood VO Superior – A591/A637

111.60 -12.53

Worcester VO Brandy – A353

111.42 -11.32

Boland VO Brandy – A532 112.89 -10.57

Final report 21


Table 3 (continue) Type of brandy Result Authentic brandy Burnham - A573 Possibly slightly adulterated with a C3 or synthetic source of ethanol. Borderline case that will

probably not be worth prosecuting, because warmer climates can also bring about higher (D/H)I values, depending on the country of origin.

Magersfontein VO Brandy – A443 Adulterated with a C4 source, i.e. cane/corn. Danté VO Brandy – no A number Heavily adulterated with a C4 (i.e. cane/corn) and possibly also a synthetic source of ethanol. My Kind’a Old Cape Brandy – A360 Heavily adulterated with a C4 source, i.e. cane/corn. Kingsman VO Brandy – A215 Very little grape spirits, mostly C4, i.e. cane/corn ethanol. Kingsfield Brandy – A419 No grape spirits, 100% C4, i.e. cane/corn ethanol. Oakhill Superior Brandy – A442 No grape spirits, 100% C4, i.e. cane/corn ethanol. Burnwood VO Superior – A591/A637 No grape spirits, 100% C4, i.e. cane/corn ethanol. Worcester VO Brandy – A353 No grape spirits, 100% C4, i.e. cane/corn ethanol. Boland VO Brandy – A532 No grape spirits, 100% C4, i.e. cane/corn ethanol.

Final report 22


Milestone 3.5. Establishment of an authorative legal-technical isotopic database of

deuterium/hydrogen (D/H) and carbon-13 ratios for the ethanol in authentic South

African brandies, inclusive of all variations caused by grape cultivar, geographic

location, still design and vintage.

See table of milestones and achievements under point 3 above.

Milestone 3.6. Objectives not realised


Milestone 3.7. Objectives completed


Milestone 3.8. Future objectives


Milestone 3.9. Publication of research results


CONCLUSIONS AND RECOMMENDATIONS

All the main aims as set out at the beginning of project WW 09/07 have been met.

Using a multi-isotopic approach and the authentic database constructed since the

onset of the project as foundation, several aspects can be investigated, i.e. to

− Screen commercial brandies to ensure legality with regard to composition,

i.e. 100% grape spirits.

− Determine whether or not alcohol from a potable non-grape source, i.e. a

grain source like maize (flavoured grain spirits) or cane spirits, has been

added.

− Determine whether or not alcohol from a non-potable alcohol source, such as

synthetic spirits, has been added.

− Effectively detect illicit spirits and prove the authenticity of South African

brandies.

Final report 23


The results from five samples are awaited and must be incorporated into the

database. Based on the fact that ageing in wooden casks for thirty six months leads

to isotopic fractionation, decision regarding the inclusiveness of all analysed ageing

samples (between 0 and 36 months) in the database must be made. The database

should also be expanded to include more matured samples. Based on the fact that

distillation does bring about isotopic fractionation in some cases, decisions will have

to be made as to whether or not brandy base, distilling and low wines should be

excluded from the authentic database. The database currently provides for the

inclusion of these components. If it is decided to exclude these components, minor

structural/ programming/ visual basic changes/ corrections of the database will have

to be made. The authentic database is used to determine whether or not a brandy

sample is possibly adulterated with non-grape ethanol or not. A decision will have to

be made as to whether or not imports should be considered part of the authentic

dataset?

A nice to have would be to have the database being able to graphically show the

95% confidence limits. This way a sample can visually and immediately be seen as

falling outside of the confidence borders/lines presented graphically. This add-on

ability will entail some designing/programming/statistical knowledge and is certainly

recommended as an additional user-friendly function making the work of the officials

at regulatory bodies or that of the authenticity expert easier.

It is strongly recommended that the database be accommodated at the ARC

Infruitec-Nietvoorbij, and that the ARC Infruitec-Nietvoorbij handle the

upkeep/maintenance of the legal-technical brandy isotopic database. Since the

establishment, all the developmental work, sampling, data entry, technology transfer

aspects, etc. have been overseen by the ARC Infruitec-Nietvoorbij, the institute is

best suited to handle these tasks. Due to year-by-year climatological fluctuations,

different and changing suppliers of brandy quality and distilling wines, new brands of

brandy and spirits coming onto the market, possible changes/adaptations in still

designs and distilling premises, operating conditions, etc., the database should be

upkept/maintained in order to maintain legal-technical trustworthiness in the long run.

Final report 24


Since upkeep/maintenance and in-house facilitation of the database will have

financial implications, a project proposal stipulating the implications for Winetech is in

writing and will follow this final report.

Several publications are in progress and will follow this final report, the time-

consuming part being the literature review and references.

4. Accumulated outputs List ALL the outputs from the start of the project. The year of each output must also be indicated.

Technology developed

An authorative database of deuterium/hydrogen (D/H) and δ13C ratios of ethanol, and

δ18O ratios in wine water in authentic South African brandies, inclusive of all

variations caused by grape cultivar, geographic location, still design and vintage.

Human resources developed/trained

One seasonal worker.

Patents

Publications (popular, press releases, semi-scientific, scientific)

Presentations/papers delivered

South African Society for Enology and Viticulture (SASEV) Congress 2006, 14 - 17 November 2006. Title: Authenticity of South African brandy. Topic: Wine chemistry Authors: F. P. van Jaarsveld, Versini G.; Augustyn O.P.H. Venue: Lord Charles Hotel, Somerset West.

© Agricultural Research Council, 2007 The content of this document may constitute valuable Intellectual Property and is confidential. It may not be read, copied, disclosed or used in any other manner by any person other than the addressee(s) and specifically not disclosed to another party submitting a proposal herein. Unauthorised use, disclosure or copying is strictly prohibited and unlawful.

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VanJaarsveldF.WW0907 Final Report - SAWIS library · A study of the influence of processing factors such as distillation and ageing on isotopic ... Several publications are in progress