Smoke and Grape – the Smoke Taint Repercussions

Aromas, Cellar, Harvest, Period 5
smoke taint

We received a large number of requests asking for practical information and scientific articles on making wine with smoke tainted grapes. Considering the devastation caused by northern California fires, we decided to share all the information we have collected regarding the effects of smoke on grapes and wine. We hope this note will provide some helpful hints and guidelines in a time of distress.


A few considerations on smoke taint

The exposure of vineyards and grapes to smoke can result in wines with undesirable sensory characteristics, such as smoky, burnt, bacon, medicinal or ash, usually described as ‘smoke tainted’.

The compounds in smoke primarily responsible for the taint are the free volatile phenols (e.g. guaiacol, 4-methylguaiacol, o-cresol, p-cresol, m-cresol, etc). These compounds are produced and released into the atmosphere when lignin in wood is burnt. The primary mode of entry for smoke-related volatile phenols into the vine, and accumulation in the fruit, is directly via the waxy cuticle on berries. When free volatile phenols enter grape berries, they can react rapidly with grape sugars to give the glycoside ‘bound’ forms of the phenols (source).

 


Glycosidic bound phenols: the ticking bomb

Free volatile phenols can be absorbed directly by grapes and can bind to grape sugars to give glycosides that have no smoky aroma. Often these glycosides are described as smoke taint precursors. During fermentation (and over time in barrel or bottle) these glycosides can break apart, releasing the volatile phenols into the must or wine, and allowing the smoky flavor to be perceived. These glycosides can also release the volatile phenols in the mouth during the drinking of wine, which may contribute to the perception of smoke taint later as wine ages (source).

 


Sensitivity to smoke exposure

The effects of smoke  vary depending on stage of grapevine growth and development when smoke exposure occurs. The nearer the fruit is to harvest the higher the risk associated with smoke exposure. Grapevine varieties differ in their sensitivity to the uptake of smoke taint compounds. Semillon or Sangiovese for instance are more sensitive than Cabernet Sauvignon (source).

 


What to do in practice?

During winemaking

As fruit is being transformed into wine, a few tips on practical management from  harvest to winemaking operations have been listed here

smoke taint

Table 1. Summary of techniques to reduce smoke-related aromas, flavors and compounds during handling and processing of grapes and wine (adapted from Brodison et al, 2013).

In the vineyard.

Research has demonstrated there is no carry-over of phenols and their metabolites from one season to the next. However, vineyard exposure to high temperatures may have long term effects.

  • To assess the potential for vine survival, a simple check consists of making a small cut with a knife to expose the tissue. As shown in Figure 1, undamaged trunk tissue remains moist and green, damaged tissue appears dry and pale and dead tissue is brown and dry.

 

smoke taintFigure 1 :  Undamaged (left), damaged (middle) and dead vine (right). Adapted from John Whitting.

  • The inflorescence initials within the buds may have been damaged by the fires. Consequently, vines may not return to full cropping levels for several years after fires and this may benefit the vine by giving it time to recover and regrow damaged tissue. For those reasons, pruning decisions on how to get the vine back into best conditions for production next year may benefit from a bud fruitfulness assessment (source).


Practical resources regarding smoke taint

Useful links about vine and smoke

Useful links about wine and smoke


Scientific references on smoke taint

Recent articles:

Older articles:

Fruition Sciences
At Fruition Sciences, we acknowledge uniqueness, natural abilities and potential growth for plants and people. While respecting tradition, we provide winemakers with a highly integrated, terroir and vintage specific, data driven web application.
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5 thoughts on “Smoke and Grape – the Smoke Taint Repercussions

  1. It would be more correct to put in quotes what you have taken from other authors in quotes. What you have done here is called plagiarism and is hardly acceptable from anyone claiming to belong to the scientific community. Would you accept someone to copy you without quoting you?

    1. Hello Eric, every source used to write that summary has been quoted and is available to everyone by clicking on the links. Thank you for reading the blog and being attentive to our content quality.

  2. Hi Fruition Sciences!

    Thank you for your always insightful posts. I am writing wondering if there’s any research on smoke taint of already fermenting wines. A large portion of wineries are in areas where the smoke is/was very thick and strong, most of which were full of both fermenting tanks in all stages and of finished wine in barrels. Very curious on what the levels may be in those wines.

    Thank you again.

    1. Hi Jennifer,

      All the scientific sources and practical information used to make this blog have been quoted within the text or listed at the end of the article under the references section. To the best of our knowledge this is all we’ve been able to find, sorry we can not help more but we will share with our community any new findings or insightful comment from our readers.

      Kind regards

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