The Effect of Half Plunging and No Plunging as Alternative Winemaking Techniques on Phenolic Extraction and Pigment Composition of Wine

Abstract

The extraction of phenolics (anthocyanins, total phenolics and tannins) and pigmented tannin evolution in Merlot red wines made using three different winemaking techniques were evaluated over one year. Traditional maceration (TM) (two plunges per day), half plunging (half) and no plunging (NP) methods were compared using triplicate 12 kg vinification. No pre-fermentation maceration occurred and a 15-day fermentation and post-fermentation period was used. The wines were analysed daily during the 15-day maceration period and regularly after pressing during the next 11 months. Phenolic, tannin and colour measurements were analysed using UV/Vis spectral readings processed using the AWRI WineCloud TM . At the end of the 15-day maceration, total phenolics, total pigment and free anthocyanins were significantly lower in concentration in the TM treatment compared with NP. The tannin concentration also was significantly lower from days 10 to 12. Pigmented tannin was consistently at higher concentrations in the TM treatment, although not significantly so, during maceration. The significant differences were maintained as the wine developed over the next 11 months; however, the NP trial wine displayed increased pigmented tannin development compared with the TM, being significantly higher in pigmented tannin from about day 90. Higher colour and phenolic extraction in the NP trial led to higher stable colour development in the resulting wines, with the winemaking having an important effect in modifying the pigment profile of the wines. General wine quality parameters did not differ significantly between the three treatments.

No Plunging and Cold Maceration followed by No Plunging as Alternative Winemaking Techniques: Tannin Extraction and Pigment Composition of Syrah and Pinot Noir Wines

“…1, both the NP and CM wines showed higher tannin concentrations during maceration from day 6 compared with the TM treatment. This is in agreement with the 2013 Merlot trials reported by Chittenden et al (2015). Tannin concentrations increased post pressing in both years.…”

“…Three replicate trials were undertaken in 2015 using Syrah and in 2016 using Pinot Noir with grapes sourced from commercial wineries in Hawke's Bay. Materials and method for the grape processing were as reported by Chittenden et al (2015).…”

“…Must analysis using methods of Iland et al (1993) determined Syrah composition as 22.0 o Brix, 6.8 g/L tartaric acid equivalent titratable acidity and pH of 3.36 and Pinot Noir composition as 22.5 o Brix, 7.0g/L tartaric acid equivalent titratable acidity and pH 3.26. The ferments and wines were analysed using the Australian Wine Research Institute WineCloud ™ (AWRI, 2012), as previously described and reported Chittenden et al (2015). Table 1 describes details of the three trial methods.…”

“…Relative colour, pigment, phenolics and tannin data were generated via the WineCloud ™ based on algorithms for this purpose using the described absorbance's to generate the relative data presented (Chittenden et al, 2015). These absorbance's are based on results from analyses according to the modified Somers and Evans assay (1977), as reported by Mercurio, D et al (2007) and Dambergs et al (2012).…”

“…On the other hand, research into minimal (no) cap management in relation to tannin and anthocyanin extraction is scarcer. Chittenden et al (2015) explored a no plunging regime effect on proanthocyanidin extraction with red wines made using Merlot, finding that phenolic and anthocyanin extractions were lower in the traditional maceration treatment compared with the no plunge treatment. Lerno et al (2018) used research scale Cabernet Sauvignon fermentations to show that pump over volume and frequency were found to have no significant effect on phenolic extraction.…”