Report

COLOR-TANNIN EXTRACTION AND STABILIZATION

 

Introduction

A significant quality parameter of red wines is the color and tannin content.  Darker wines are perceived as higher quality and overall tannin concentration can impact mouthfeel, structure, stability, astringency and perception of overall quality of the wine.  Numerous techniques have been shown to increase extraction of both color and tannins, however stabilization of the extracted compounds can be elusive.

In this trial the combination of a specific enzyme, Lafase HE Grand Cru, and joint application of two different fermentation tannin products, Laffort Tanin VR Supra (or Elegance) and Tanin VR Color, will be tested for the selective extraction and stabilization of both color and tannins in red wines.

Experimental Question(s): Can significant levels of color and tannin be extracted and stabilized in red wines through proper use of enzymes and fermentation tannins? Does this positively impact the sensory perception of the resulting wines?

Strategy: In parallel tanks use two different process regimens in the extraction and stabilization of red wine lots from the same vineyard.  Experimental Protocol – HE Grand Cru, Tanin VR Supra, Tanin VR Color.

The control for this trial can be the standard winery process so long as that process is not the same as the experimental process.  Use of competitor enzymes and/or tannins can act as a control against the application of the experimental protocol of HE Grand Cru and the combination of Tanin VR Supra and Tanin VR Color.

Varietals – Red wine varietals are all applicable with the exception of hybrid varietals. Cabernet Sauvignon, Merlot, Syrah, Pinot Noir, etc.

Process conditions – Standard red winemaking practices should be followed, processes such as thermo-vinification or Flash Détente should not be a part of this trial. Cold soaks and extended maceration practices can be integrated into this trial with some modifications of product application timing and dosage.  Basic process should involve tank fermentation followed by cellar ageing in either tank or barrel.

The general procedural guidelines listed below may not be ideal for all participating wineries and some variation may occur.  The winery variability was discussed in project harmonization meetings before harvest and all changes were determined to be acceptable.  The slight processing variations builds robustness into the trial and in no way eliminates the individual trial iteration from proper comparison with other trials.

To illustrate the synergy possible between enological enzyme application and fermentation tannin addition a trial using red grapes was designed as follows.

  • Lafase HE Grand Cru is a premium maceration enzyme intended for structured red wines
  • Tanin VR Supra is a fermentation tannin which provides structure, anti-oxidant capacity and protein binding to preserve grape skin tannins
  • Tanin VR Color is a fermentation tannin with high reactivity towards anthocyanins to preserve color in red wines

General Concepts

  • This is a very straight-forward trial with the control being no treatment (or winery standard) versus the experimental treatment of the combination of Lafase HE Grand Cru enzyme with Tanin VR Supra (Elegance) and Tanin VR Color.
  • Post fermentation cellaring should be at least one year from the end of fermentation to allow stabilization and structure impacts to be observed.

Dosages

  • Lafase HE Grand Cru dose should be 40 g/ton (HEGC enzyme dose may be reduced to 20 g/ton or substituted by Lafase Fruit for Pinot Noir) enzyme should be applied according to preparation instructions at the crusher or during a pump-over.
  • Tanin VR Supra (Elegance) dose should be 200 – 400 ppm tannin should be applied according to preparation instructions at the crusher.
  • Tanin VR Color dose should be 200 – 300 ppm ( 200 ppm for Pinot Noir, 300 ppm for other varietals) tannin should be applied according to instructions at approximately 5 brix drop during fermentation.

Sample – Time points – Documentation

  • Documentation of region, vineyard, varietal, processing parameters, fermentation additions (SO2, enzyme, yeast, nutrients, etc.), as well as YAN analysis and routine chemical analysis throughout the winemaking process.
  • Samples (2 x 750mL) for analysis should be collected at both 6 months and 12 months post-fermentation. Analysis at these time points will be the Rapid Phenolic Panel (ETS) (includes catechin, tannin, quercetin glycosides, polymeric anthocyanins, monomeric anthocyanins) and a simple A520 color measurement done by ARC member lab. Bogle Winery graciously volunteered to run the A520 for all samples.
  • Samples (2 x 750mL) for sensory tasting at 6 month time-point will be evaluated by ARC member panel.
  • Samples (6 x 750mL) for sensory tasting at 12 month time-point will be evaluated by ARC member panel and at the ARC Annual Strategic Planning Meeting.
  • Sensory evaluation of wines at 12 months or blending/bottling – as late as possible with trial lots kept separate.
  • Difference, Preference and Descriptive (complexity, intensity) testing will be performed.

Analyses

  • Rapid Phenolics Panel – ETS Labs
  • A520 – to be done by single volunteer ARC winery – Bogle Winery
  • Wine Chemistry – to be done by participating winery
  • Sensory Evaluation, difference and preference testing – by ARC member sensory panel

ARC Summary

Trial commitments/completed trials                        20 / 11

ARC member tasting panel opportunities              1 (Santa Rosa)

Presentation of Color/Tannin Trial Wines               2 Events, 7 wines presented (control and treatment for each)

ARC 2017 Strategic Planning Meeting – Van Duzer Vineyards, Sonoma-Cutrer Vineyards, 14 Hands Wine, Trinchero Family Vineyards, Hope Family Wines

North Coast Wine Industry Expo – Van Duzer, TBD

Trial Results

 

Quantitative Results sectioned by method

 

ARC Member Winemaker Tasting Panel Sensory Evaluation

 

Case Study A –

 

Case Study B –

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