Report

RED PRESS FINING

 

Introduction

In red winemaking, press wines may account for a significant part of the volume. Beside the quantitative aspect, these wines have qualitative aspects that winemakers can benefit from by blending them with free run wines. Rich in flavors, phenolic compounds and in color, press wines bring roundness and volume to the blend, therefore nicely complementing wines that may lack structure.

Integration of red press wines in the blend is common, yet it is not an easy practice. It requires trials and tasting because the press wines are expected to:

a) Not unbalance the polyphenolic structure and bring a perception of green or metallic character
b) Not have a negative impact on wine clarity
c) Not destabilize the wine color
d) Not contaminate the free run wine with spoilage micro-organisms

In many cases, press wines are aged separately and added only during final blending, generally after a filtration. This practice can be optimized, for many reasons: early blending ensures that free run and press fractions meld best in terms of length in mouth and final wine structure. Additionally, filtration addresses immediate clarification concerns, but it can also lead to stability issues on complex matrices like a press wine, the filtration can retain protective colloids and therefore create colloidal instability of the filtered wine.

In order to optimize the integration of press wine, trials of early fining will be performed just after pressing. The subsequent analyses include microbiological and turbidity measures, intensity and stability of coloring matter evaluation, as well as astringency and organoleptic perception of the wines.

The control in this trial will consist of standard winery practice in segregating and handling red press wine and should be described in detail for each individual winery participating in this trial.

The experimental arm of this trial will involve an early fining of the red press wine with various agents along with the appropriate measurements as described on both control and trial wines.

Varietal:                               All red wine varietals

Process conditions:         Standard red wine fermentation conditions with separation of free-run wine drain followed by pressing off of residual cap solids.

Other specifics:                 Free-run and press wine should be held separately until trial processing of the press fraction has been completed.

Red wine to be vinified with standard practices. Post-fermentation free-run wine to be held separately from press wine.

Press wine to be segregated as “low-pressure” (less than ~0.8 bar) which can be added directly to the free-run fraction and “high-pressure” (greater than 0.8 bar) fraction which will be subjected to fining trials.

Press wine (greater than ~0.8 bar) to be allocated and treated with Extralyse™ glucanase enzyme and various fining agents and held 1 week before racking off gross lees, analyses completed, and either held separately or added to free-run fraction for MLF completion and blending. Timing of press fraction addition back to free-run may be variable depending upon individual winery procedures.

Critical experimental processes and measurables

  • Separation of free-run and press lots
  • Fining agent dosage and documentation of procedures

 

Samples(4)                                         Timepoint                                                           Measurables

Free Run + ?Lt Press Wine?          post-fermentation (after settling)              [A280-420-520, ETS Rapid Phenolics Panel, –

Press Wine (?< 0.8 bar?)                post-fermentation (before settling)           Combined Spoilage Scorpions analysis]

Fining Treatment Press Wine      post-fermentation (after settling 1 wk)     [sensory evaluation, pH, TA, color stability]

No Treatment Control                  post-fermentation (after settling 1 wk)     [color stability test]

 

www.etslabs.com/analyses/%23GEXT        ETS Rapid Phenolics Panel analysis  (see link for sampling)

www.etslabs.com/analyses/%24WSP         ETS Scorpions Yeast & Bacteria Panel analysis (see link for sampling)

 

Write WINERY NAME and ARC on all samples!

Perform Color Stability Test and A280, A420, A520 in house

Record Gal/Ton free run wine and volume of press collected

Record Lees compaction volume and settling time in house

Perform sensory evaluation of all samples in house, get 3 evaluations, record comments on press wine characteristics

 

Enzyme                                                                Dose

Extralyse™ glucanase enzyme                    100 ppm

 

Fining Agents                                                     Dose                                                      Settling time

Gelatin (Gecoll Supra)                                    40 – 100 mls/hL                                1 – 3 weeks

Patatin (Vegecoll)                                            30 – 60 ppm                                        1 – 2 weeks

Polymust Press                                                 250 – 400 ppm                                   1 – 2 weeks

 

Color Stability Test Protocol

Pass wine sample through 0.45 filter into clear glass sample container

Measure wine A520 before incubation

Place sample in refrigerator (4°C) and leave for 48 hours

Remove sample from refrigerator and leave at room temperature for 30 – 60 min

Inspect bottom of glass sample container for visible precipitate

Measure wine A520 after incubation and temperature equilibration

Note any precipitate (+,-   amount,  color) if no visible ppt, measure wine A520 and compare to pre-incubation sample

 

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