Flavour Chemistry 10/02/2020

Prof Kieran Kilcawley Teagasc Food Research Centre Moorepark, Fermoy, Co. Cork kieran.kilcawley@teagasc.ie

Project: Whiskey Terroir Enterprise Ireland Innovation Partnership with Waterford Distillery

Project Background • Is there a terroir in Whiskey? (what is Terroir?)

• Terroir is the set of all environmental factors that affect a crop’s phenotype (physical expression), including unique environmental contexts, farming practices and a crop’s specific growth habitat.

• Collectively, these contextual characteristics are referred to as “terroir”.

• Terroir forms the basis of the French wine appellation d’origine contrôlée (AOC) system, which is a model for wine appellation and regulation in France and around the world.

• Recent studies in the USA are linking Terroir to beer. • Thus why not Whiskey?

• Waterford Distillery • As Waterford malt and distil each suppliers barley separately they

are in a unique position to assess each spirit independently. Their own anecdotal evidence from tasting suggests differences in the spirit (before aging in barrels) differs between individual farms

• Terroir forms the basis of their product differentiation and their first whiskey comes on sale in 2020

• Project – Innovation Partnership with Enterprise Ireland • They designed a mini project with Minch Malt growing two types of

barley in Ireland (Bunclody and Athy), malted, fermented and distilled at pilot scale level over 2/3 yrs

• Expertise from Oregon State University (USA), Tatlock & Thompson (UK) and Teagasc

Project Background

• Project – Innovation Partnership with Enterprise Ireland • We (Teagasc) were approached in 2016 to see if we could bring

our expertise in flavour chemistry in an attempt to prove the potential existence of terroir for whiskey in an Irish context

• Flavour Chemistry

Project Background

Sample Extraction

/Concentration GCMS Data

Processing

What is flavour? • A component of our sensory experience “A scientific discipline used to evoke, measure,

analyze and interpret those responses to products that are perceived by the senses of sight, smell, touch, taste and hearing.”

• Flavour is used to describe the perception of taste and smell (aroma). Aroma has a much bigger contribution than taste

Directly by Orthonasal Detection: Odour is best reserved for the smell of food (before it is put into the mouth)

• Comprised of taste and aroma (ratio 1:4) • Volatile aromatic compounds have a

greater role in flavour perception • Volatile compounds can reach olfactory

receptors by two ways

Indirectly by Retronasal detection via the throat: Aroma is the retronasal smell of food in the mouth

Olfactory bulb What is flavour?

Experimental design

Extraction Technique

Head Space-Solid Phase Microextraction

Separation & Detection Technique

Gas Chromatography Mass Spectrometry

Sampling

SPME holder

Fiber withdraw

Fiber

Sample

Desorption

To MS

GC column

Placed into GC injector port

Low Wines

Spirit Sample

Distillation

Samples

Feints

Foreshots

Barley

Variety Location

Athy

Bunclody

Laurate

Olympus

Low wine production

Fermentation

Spirit production

Low wines 2nd charge +

Foreshots & Feints from 1st

charge

Spent Lees***

Pot A le**

Draff*

Malt

Hot Water

Mash

&

Mashing

Low wines ~20%

Wash ~8%

Wort

Wort

Wash

Low wines 1st charge

Low wines 2nd charge

Foreshots& Feints

(charge 1)

Foreshots

Spirit Sample 1

Spirit Sample 2

Process

Results: Variety Effect

Isobutyl decanoate

Isobutyl octanoate

Isoamyl octanoate

2-Methylbutyl octa

2-Methylbutyl deca

Ethyl heptanoate

Ethyl dodeca

Isoamyl decanoate

Ethyl octanoate

Farnesyl acetate

Ethyl hexanoate

Propyl decanoate

Decyl acetate

2,3-Dihydro farnesyl acetate

Hexane, 1,1-diethoxy-

Ethyl nonanoate

Dimethyl disulfide

Ethyl butyrate

Ethyl undecanoate

Ethyl propanoate

Ethyl trans-4-decenoate

Butane, 1,1-diethoxy-3 Propane, 1,1-diethoxy-2-methyl-

Isobutyl acetate

Ethyl acetate

Ethyl pentanoate

Ethyl decanoate

Decanal

Undecanal

Isobutyl hexanoate

-10

-5

0

5

10

-10 -5 0 5 10Dim1 (27.2%)

Dim

2 (2

2.3%

)

Groups

Laurate

Olympus

SS1 variety

74 volatile compounds were identified in sprits, mainly ethyl esters (fruity flavours)

Results: Location Effect

Isobutyl decanoate

Isobutyl octanoate

Isoamyl octanoate 2-Methylbutyl o

2-Methylbutyl deca

Ethyl heptanoate

Ethyl dodec

Isoamyl decanoateEthyl octanoate

Farnesyl acetate

Ethyl hexanoate

Propyl decanoate

Decyl acetate

2,3-Dihydro farnesyl acetate

Hexane, 1,1-diethoxy-

Ethyl nonanoate

Dimethyl disulfide

Ethyl butyrate

Ethyl undecanoate

Ethyl propanoate

Ethyl trans-4-decenoate

Butane, 1,1-diethoxy-3-methy Propane, 1,1-diethoxy-2-methyl-

Isobutyl acetate

Ethyl acetateEthyl pentanoate

Ethyl decanoate

DecanalUndecanal

Isobutyl hexanoate

-10

-5

0

5

10

-10 -5 0 5 10Dim1 (27.2%)

Dim

2 (2

2.3%

)

Groups

Athy

Bunclody

SS1 location

Results Seen a bigger

impact of location than barley variety

This suggests a potential terroir effect

Much more to do

Lots of process factors

Trying to find out what are the key volatiles that impact on sensory perception as many do not

• Olfactometry • Determine odour activity of individual volatile

components • We can identify the most important volatile

compounds • Trained panellists sniff GC outlet, • Odour activity

• Concentration of the compound and its odour threshold ( the concentration when you can perceive a smell)

On going research…

On going research…

On going research…

5x10

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Counts vs. Acquisition Time (min)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

+EI TIC Scan SS2_206D2.d

GCO analysis in Spirits

1.43 alcohol 2.03 acidic 2.33 corn/ cabbage 3.20 floral/ butter/ grass/ brett 3.97 sweat 4.30 vinegar/bad smell/glue 5.15 butter/baked/fruity 5.33 butter/grass/fruity/chocolate 5.94 butter/burnt/plastc 6.71 fruity/floral 6.81 pineapple/apple/fruity/ 7.90 Fruity/sweet/cherry/apple 8.03 fruity/sweet 8.15 herbal/rancid/buttermilk 9.16 fruity/ apple 9.22 toasted/baked/coffee 9.50 green/vegetative

10.55 pineapple/ apple/cherry/fruity 10.70 pineapple/stewed pineapple/ mint/ herb 11.20 baked/ toasted almond/dry fruit/ 11.50 fruity/cherry/melon/banana 12.20 bad smell/ stable/butter 12.50 bad smell/ fish/ seaweed/grass/rubber 13.31 boiled potato/ pyrazine/pet food 13.80 fruity/butter 13.96 flower/fruity/herbal/marker ink 14.36 bad smell/ gas/ burnt/pungent 14.70 metallic/ mineral/whiteboard marker ink 14.89 pineapple/ pear/ fruity 16.27 soil/ herbal/grass/ burnt/gas 17.16 flower/ rose/ honey 17.28 cut grass/ green bell pepper/ pyrazine 17.35 green leafs/grass/ green/ cabagge/vegetable 17.73 coffee/ sweet 18.07 soap/ fresh 19.22 chemical/ lemon/very intense smell 19.40 rose/ floral/ metallic/marin-like/ sea salt 19.80 fried/ toasted/grass/ bad smell/SO2 20.20 grass 20.89 grass 21.30 cheesy/ fatty/ grass/floral 21.56 herbal/ fresh/grass/gas/petrol/floral 22.30 herbal/fresh/ solvent 22.90 irritant 23.03 plum/ honey/ tea/ dry fruit

Teagasc Personal on Project – Whiskey Terroir Prof Kieran Kilcawley

Dr Maria Kyraleou

Any Questions?