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Whisky Fraud - Chemical Analysis Used To Detect Fake Spirit

You need to know that the whisky in your collection is legitimate. With record prices being paid for whisky at auction, and a highly competitive market-place for exclusive bottlings, the door has opened for fraudsters to make a quick profit.

Below is a summary of recent advances in laboratory techniques targeted towards assisting the detection and therefore prevention of fraud in the whisky industry.

As a founding member and Secretary of a whisky tasting society and a collector of whisky, I have a keen interest in understanding the scotch whisky market. Scotch is Scotland’s gift to the world and due to the current boom in sales it brings a significant income into the economy.

Annual export sales are nearly £5bn with an average of 42 bottles shipped worldwide every second (SWA report). Secondary markets are also hitting the headlines with sales such as a Macallan 1926 reaching an auction record of £1.5m in October 2019.

Because of this the opportunity to make money from fake goods has grown. An Interpol investigation called Operation Opson V in 2015, covering 57 countries, discovered a huge quantity of illegal spirits including whisky, found amongst 10,000 litres recovered in the UK alone.

Scotch whisky is geographical protected and controlled through legislation following guidelines set out by the Scotch Whisky Association. It has to be distilled, matured and bottled in Scotland, but the list of specifications is long. There are therefore many opportunities to fake whisky such as disguising younger or cheaper whisky, or simply using pretend coloured liquid. Some disguises are clearly more easy to spot such as this Egyptian version of Chivas Regal 18 year old whisky.

Replacing the contents of an original bottle would be difficult to spot especially as bottles of rare whisky are rarely opened. How am I to tell that the whisky in the bottles from my own collection are as shown on the label? With a piece of fine art you can see and feel the brushstrokes of the master, but this is just an amber coloured liquid behind glass.

In the next few slides I am going to describe two laboratory processes that have been used to define scotch whisky.

The first is a method of determining the age of whisky, as old whisky is rarer and therefore has a premium price. This process is called radiocarbon dating and this can be used to create a library of data for whiskies of all ages, against which fake whiskies can be compared.

The second is a method for analysing the chemical components of the liquid by gas chromatography and mass spectrometry. Producing chemical recipes for a broad range of whiskies will also provide a reference database with which to compare possible fake whiskies.

Radiocarbon dating is a process that determines the amount of a carbon-14 in a test sample. Carbon-12 makes up 99% of all carbon on Earth whereas carbon-14, a heavier atom with 2 extra neutrons, is a very rare form. In the 1950s and 1960s the atom bomb tests increased the amount of carbon-14 in the atmosphere and since then the levels have been dropping steadily as shown in the graph here. Carbon-14 is taken up into the tissues of all living things, plants and animals, during their life.

Carbon-14 can be found in whisky because it will have been present in the barley it is made from. Knowing the level of carbon-14 in a whisky sample can be used to confirm the age.

Mass spectrometry is the method used for finding the level of carbon-14 in a test sample. As the process is examining samples at the atomic level it requires large specialised equipment that would fill a room, however the principle of the method is that you can separate atoms because of differences in their mass. The equipment pushes atoms at high speed and then counts them as they pass detectors which are types of cameras.

In this analogy shown if you pushed a motorbike, a car, and a bus down a long hill the heaviest, the bus, would travel further. With cameras at the bottom of the hill you could record each vehicle as it stopped. Imagine the bus is carbon-14, the car is carbon-13, and the motorbike is carbon-12. Each has different mass and so can be separated by the distance travelled down the hill.

This method has been used to find the amount of carbon-14 in 211 control whisky samples distilled between 1950 and 2015. The results are plotted on this graph in red and they align really well with the original data from tree rings and atmospheric samples, shown in black. The small difference between the black and red line is about one year, the time it takes for barley to grow and then to be harvested and distilled into whisky. We now have a library of data against which to test unknown possibly fake whiskies.

If a test sample produces a carbon-14 value of 1.5 on this scale then drawing a line across the graph at this point will give a range of possible dates from the mid 1960s to the early 1970s (green hatched box).

Analysis of seven rare, old whiskies from across Scotland showed that the age ranges were inconsistent with the bottle label in three cases.

When this result was published there was a significant degree of apprehension amongst collectors of old whisky although it is not known exactly how many of these were going to volunteer to have their collections verified. Whisky samples for this work were supplied by Diageo, Edrington and Rare Whisky 101.

The second method to discuss here is a combined process of gas chromatography and mass spectrometry, used to find the chemical recipe of whisky.

Gas chromatography is a method of sorting chemicals in a sample and at the heart of the equipment is a column or tube, that is usually coiled to fit a long length within a smaller box.

The column, represented in the cross-section diagram, contains both liquid and gas phases, and as the samples are pushed through the chemicals will travel at different rates according to their size, electrical charge, and volatility. Small molecules will travel faster than larger ones and those that are more volatile will travel faster in the gas space.

Once though the column the chemical molecules enter a mass spectrometer as per the previous method – although this time it is a smaller instrument as it is looking at larger molecules and not individual atoms.

The data from each test sample is a list of chemicals present – the whisky recipe.

The data shown below follows statistical analysis (PCA - Principal Component Analysis) of the chemical lists from 171 real whiskies and 20 fakes supplied by the Scotch Whisky Research Institute. The analysis shows clustering of samples with similar chemicals in their lists and it can be seen that the genuine and fake whiskies cluster into separate groups. A few of the fake whiskies are close to the genuine whisky data, this is due to the minor changes in some real whiskies to make fakes.

With recent advances in microelectronics the gas chromatography / mass spectrometry equipment is now contained in a benchtop sized instrument that is more affordable, is faster, and will generate data of higher quality.

The Thermo Fisher Q Exactive instrument shown on the right was used to analyse whiskies from around Scotland and the USA and which had been matured for different lengths of time.

The comparison charts produced in this experiment show the resolution of regions, for example you can see the separation of the three whiskies from the Campbeltown region (once known as the Whisky Capital of the World with 30 distilleries), and the American bourbon is distinct at the top of the chart. You can also distinguish the different aged whiskies from one distillery – 12 and 18 year old and the mixed blend of ages in the no age statement sample.

So to summarise I have taken you through age verification of whisky using radiocarbon dating and mass spectrometry. Then whisky chemical recipe analysis by gas chromatography and mass spectrometry.

The future looks promising, to the analysis of whisky whilst still in the bottle, potentially using a hand-held instrument such as the one shown on the right of the slide that is already in use for chemical and drug analysis. That would provide a more streamlined, faster means to protect Scotland’s national drink.

These are the sources of the work discussed, if you wish to read further into the methods used there are links to the PDFs below.

Document PDF Links

Radiocarbon Dating by Cook

GC/MS by Stupak

Chemical Profiling by Roberts