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.