18 November 2016

Compass Box Hedonism, Triangle Test ISO 4120

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Compass box shares information on internet via multiple channels one of which is twitter. 

Compass Box Tweet, screencaptured
Consistency in whisky is important for blends and single malts alike. I took this tweet by compass box as an opportunity to find out how whisky-makers do this.

What can we learn from this tweet and what can we learn from the photo?

The first thing I see are the three black ISO 3591:1977 sensory analysis - apparatus - wine tasting glasses. There glasses are prescribed when doing sensory evaluations of liquids, such as whisky. I have blogged about these glasses before. See this link.

The black glasses are to prevent the assessor from identifying any visual differences between samples by looking through a transparent glass. This prevents identifying the odd one out and thus influencing the assessor.

Photo by Compass Box, linked to twitter URL
The "blind triangular tasting" that is mentioned is standardised via a number of ISO standards, depending on how the tasting is performed and for which purpose the tasting is performed.

In total there are 17 ISO standards in the "Sensory analysis -- Methodology" section.

These are:
  1. ISO 5497:1982 Sensory analysis -- Methodology -- Guidelines for the preparation of samples for which direct sensory analysis is not feasible
  2. ISO 8588:1987 Sensory analysis -- Methodology -- "A" - "not A" test
  3. ISO 11036:1994 Sensory analysis -- Methodology -- Texture profile
  4. ISO 16820:2004 Sensory analysis -- Methodology -- Sequential analysis
  5. ISO 5495:2005 Sensory analysis -- Methodology -- Paired comparison test
  6. ISO 11056:1999 Sensory analysis -- Methodology -- Magnitude estimation method
  7. ISO 4120:2004 Sensory analysis -- Methodology -- Triangle test
  8. ISO 10399:2004 Sensory analysis -- Methodology -- Duo-trio test 
  9. ISO 8587:2006 Sensory analysis -- Methodology -- Ranking
  10. ISO 6658:2005 Sensory analysis -- Methodology -- General guidance 
  11. ISO 13301:2002 Sensory analysis -- Methodology -- General guidance for measuring odour, flavour and taste detection thresholds by a three-alternative forced-choice (3-AFC) procedure
  12. ISO 5496:2006 Sensory analysis -- Methodology -- Initiation and training of assessors in the detection and recognition of odours
  13. ISO 29842:2011 Sensory analysis -- Methodology -- Balanced incomplete block designs
  14. ISO 3972:2011 Sensory analysis -- Methodology -- Method of investigating sensitivity of taste
  15. ISO 11132:2012 Sensory analysis -- Methodology -- Guidelines for monitoring the performance of a quantitative sensory panel
  16. ISO 11136:2014 Sensory analysis -- Methodology -- General guidance for conducting hedonic tests with consumers in a controlled area
  17. ISO 13299:2016 Sensory analysis -- Methodology -- General guidance for establishing a sensory profile
From the word "triangular" in the compass box tweet I deducted that this could be the ISO 4120:2004 methodology. So I asked on twitter and the answer was positive. I found a legal copy of this standard and started reading.

Photo by Compass Box, linked to twitter URL
In the photo you see the glasses standing in a triangle. This is according to point 7.2 of the standard. Tasting is done from left to right. Two of the glasses are filled with the same sample of the product. The third glass is filled with the other sample product. Six sets of combinations of these samples are possible and the assessor is not aware of which set sample is in which glasses.

Below the glasses are three numbers. These are chosen at random by the person that is setting up the procedure. Only the person setting up the tasting knows which numbers correspond with which product. The numbers intentionally mean nothing to the assessor so to not cause bias.

The assessor in this form used by compass box fills in the number of the sample that is the one that he or she thinks is different. What is not part the standard is filling out the level off similarity on a scale from one to ten. So maybe this is not the ISO 4120 after all ;)

This ISO 4120 test can be done in order to either
- see if the assessor is able to spot the odd one out in order to show that the odd one out is indeed different,
- see if the assessor is not able to spot the odd one out in order to show that the odd one out is indeed "similar"

This last kind of test is what compass box wanted to show here. Is the new batch of hedonism so similar that the assessor cannot spot the odd one out.

The standard gives a definition for “similar” which reads: situation in which any perceptible differences between the samples are so small that the products can be used interchangeably

That is off course what John Glaser wants, consistency between two batches of hedonism. The batches of hedonism used here are two glasses of the May batch and one glass with the February batch.

I trust the batches were indeed found similar.

In other blogs I will go into the other ISO standards that give details on how to properly taste, nose, make tasting notes, rate etc. As a whisky nerd I find this all very interesting indeed. I would love becoming an assessor. The training of the assessor is also standardised in an ISO standard. The training of the coordinator is standardised, the glasses are, the preparations of the samples, the cleaning of the glasses, the room, the layout of the room, the tasting notes, the scoring etc. Etc. All is standardised in ISO standards.

I wonder how many bloggers follow these standards. I hope a lot. But I suspect very little even have the slightest notion. This needs to be remedied. In blogs to follow I shall go into these standards one by one so I can educate myself. That is, if I can find copies of the standards ;)

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