Smoke Taint and Mirrors

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Smoke Taint and Mirrors

• Some observations about smoke effect, its cause,
  and its removal

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Guaiacol in Berries(Samples analyzed at ETS from
Aug to Oct 2008)
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Winesecrets Experience

• Smoke removal in British Columbia
• Technology transfer
• Operations, lessons learned
• Started Mendo removal operations in late 2008
• To date, over 1,500,000 gallons successfully
  restored

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Smoke Composition
Pyrolysis of burning material also results in
production of a large amount of hydrocarbons,
both aliphatic (methane, ethane, ethylene,
acetylene) and aromatic (benzene and its
derivates, polycyclic aromatic hydrocarbons e.g.
benzoapyrene, studied as a carcinogen, or
retene), terpenes. Heterocyclic compounds may be
also present. Heavier hydrocarbons may condense
as tar. Presence of sulfur can lead to formation
of e.g. hydrogen sulfide, carbonyl sulfide,
sulfur dioxide, carbon disulfide, and thiols
especially thiols tend to get adsorbed on
surfaces and produce a lingering odor even long
after the fire. Partial oxidation of the released
hydrocarbons yields in a wide palette of other
compounds aldehydes (e.g. formaldehyde,
acrolein, and furfural), ketones, alcohols (often
aromatic, e.g. phenol, guaiacol, syringol,
catechol, and cresols), carboxylic acids (formic
acid, acetic acid, etc.). The visible particles
in such smokes are most commonly composed of
carbon (soot). Other particulates may be composed
of drops of condensed tar, or solid particles of
ash. The presence of metals in the fuel yields
particles of metal oxides. Particles of inorganic
salts may also be formed, e.g. ammonium sulfate,
ammonium nitrate. Many organic compounds,
typically the aromatic hydrocarbons, may be also
adsorbed on the surface of the solid
particles. Some components of smoke are
characteristic of the combustion source. Guaiacol
and its derivatives are products of pyrolysis of
lignin and are characteristic of wood smoke
other markers are syringol and derivates, and
other methoxy phenols. Retene, a product of
pyrolysis of conifer trees, is an indicator of
forest fires. Levoglucosan is a pyrolysis product
of cellulose. Hardwood vs softwood smokes differ
in the ratio of guaiacols/syringols.
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Smoke Analysis

• ETS
• Eric Herve
• Vinquiry
• Jerome Lillis
• Field analysis
• UV Spec
• Wine glass

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Guaiacol and 4-Methylguaiacol
Markers

• G smoky, charred
• 4MG smoky, spicy

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Smoke Taint Characteristics

• Aromas Ashy, tar, BBQ, creosote, cold fire
• Bitter phenolic, metallic taste
• In Whites
• Occasionally taste in grapes in vineyard
• Aromas found early in white juice
• In Reds
• Occasionally taste in grapes in vineyard
• Sometimes discovered during fermentation
• Easily spotted post ML

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Available Research

• Most papers concern analysis for guiacols
• Understanding uptake mechanisms
• Developing predictive model of guiacol levels in
  grapes and finished wine.
• Most research from Australia
• Australian Government Grape and Wine Research
  Corporation
• Australian Wine Research Institute
• Authors most active
• K. R. Kennison
• K. L. Wilkinson

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Canadian Research

• Effect of Pre- and Postveraison Smoke Exposure on
  Guaiacol and 4-Methylguaiacol Concentration in
  Mature Grapes
• Stacey I. Sheppard1,1, Manpreet K. Dhesi2,2 and
  Nigel J. Eggers3, 1, 2 Research assistant and 3
  Associate professor, Chemistry, Earth
  Environmental Sciences, Irving K. Barber School
  of Arts Sciences, University of British
  Columbia, Okanagan, 3333 University Way, Kelowna,
  BC, V1V 1V7 Canada.
• Corresponding author (email nigel.eggers_at_ubc.ca
  )
• Chardonnay, Merlot, and Pinot gris grapes were
  treated with smoke generated by the combustion of
  Ponderosa pine at preveraison, postveraison, and
  maturity. Guaiacol and 4-methylguaiaol
  concentrations were determined in the mature
  harvested grapes using a stable isotope dilution
  assay. Both guaiacol and 4-methylguaiacol were
  sorbed by the grapes during the smoke treatments
  and remained until the grapes were harvested.
  There was a general trend for increasing sorption
  of guaiacol and 4-methylguaiacol as grapes
  matured. A positive linear correlation was
  observed between the guaiacol4-methylguaiacol
  ratio and guaiacol concentration for all
  smoke-treated grape samples that had
  concentrations above detection limits. Guaiacol
  concentrations ranged from 2 to 26 µg/L. These
  grapes could yield a wine where the
  concentrations exceed the detection threshold of
  guaiacol and the concentrations were of the same
  order as that resulting from contact with oak. An
  hour of smoke exposure would have an impact on
  the sensory characteristics of the resulting
  wines.

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Research (most pertainent)

• Department of Primary Industries Victoria Mark
  Krstic John Wihting 2003
• British Columbia Fire (Okanagan Valley) AWS Work
  experience 2003
• UoA Analysis and Amelioration of Smoke Taint
  Dr. Kerry Wilkinson 2007
• Technical Workshop Smoke Taint AU Government
  Mark Krstic 2008
• Western Australia Department of Agriculture and
  Food 2009
• Bushfire Generated Smoke Taint in Grapes and
  Wine Kristen Kennison
• Western Australia Department of Agriculture and
  Food 2009
• Latest developments Kristen Kennison

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Australia what is known

• What we know
• Smoke taint/effect carryover from one season to
  another is not a problem.
• Guaiacol indicator compound involved , but not
  necessarily responsible for smoke
• taint (it is also found in oaked wine products).
• Safe to burn after grape harvest (the date
  varies depending on growing region and
• grape variety).
• Taint compounds durable in wine (that is
  compounds only get worse with age of wine).
• Guaiacol and 4-methylguaiacol increases during
  fermentation as it is extracted into
• solution.
• Problems in current guaiacol and
  4-methylguaiacol analytical methods (some grape
• samples can come back with not detected levels of
  indicator compounds, but still show
• taint in wine).
• Highly variable between varieties (some grape
  varieties more sensitive than others).
• Cumulative affect of smoke (increased smoke
  exposure increased risk of being
• affected).
• Smoke more from a filtration perspective, but
  we dont know all
• the taint compounds. affects grape vine
  physiology (i.e. yield and photosynthesis).
• Peak in sensitivity at 7 days post-veraison
  from WA research trials.
• Wines from white grapes is less affected than
  wine from red grapes (this is due to skin

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Australia what is not known

• Mode of smoke entry into vine and fruit
• Sensitivity and timing of vines to smoke
  exposure
• Effect of distance, composition, concentration
  and duration and entry into the vine (models)
• Fire source (fuel types), smoke composition and
  affect on vines
• Localization of smoke taint compounds in grape
  berries
• Pre-cursor and conjugates in grapes (what are
  they?)

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Smoke removal research

• Only one paper focused on removal methodology
• Kerry Wilkinson, The University of Adelaide, The
  Analysis and Amelioration of Smoke Taint
• Conclusion RO and Carbon adsorbsion reduced
  guiacol indicators (12 to 5 ppb), no effect on
  wine quality parameters, profound effect on
  sensory qualities

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Smoke Removal Technologies

• Reverse Osmosis
• Pressure/pore size
• Carbon block
• Granulated carbon
• Resin

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Alternatives

• Harvesting/grape handling
• Pick at night
• Washing not effective
• Reduce skin contact
• Fining
• Vinquiry has a product that combines eisenglass,
  bentonite and carbon that has been effective at
  low levels of guiacol
• Other fining strategies may help, no evidence of
  consistent results
• Masking with oak
• No record of effectiveness
• Blending
• If you can afford it

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Frequently Asked Questions

• The best questions are those yet unasked!