Bunch microclimate influence amino acids and phenolic profiles of Pinot noir grape berries.

Introduction: The increase of temperature due to climate change at different phenological stages of grapevine has already been demonstrated to affect accumulation of primary and secondary metabolites in grape berries. This has a significant implication for Pinot noir especially in New Zealand context as these compounds can have direct and indirect effects on wine quality.

Methods: This study investigates how varying bunch microclimate through changes in temperature applied at veraison stage can affect: fresh weight, total soluble solids, the accumulation of anthocyanins, total phenolics and amino acids of the grape berries.

Substitution or Dilution? Assessing Pre-fermentative Water Implementation to Produce Lower Alcohol Shiraz Wines.

Changes to regulations by Food Standards Australia New Zealand have permitted the adjustment of must sugar levels with the addition of water in order to ensure a sound fermentation progress as well as mitigating excessive wine-alcohol levels. This study assessed the implications for Shiraz wine quality following a pre-fermentative must dilution (changing liquid-to-solid ratios), in comparison to juice substitution with water (constant liquid-to-solid ratios) that has previously been deemed a promising way to adjust wine-alcohol levels. While working within the legal limit of water addition to grape must, the effects of both approaches on wine quality parameters and sensory characteristics were rather similar, and of negligible nature.

Pre-fermentation approaches to producing lower alcohol wines from Cabernet Sauvignon and Shiraz: Implications for wine quality based on chemical and sensory analysis.

Pre-fermentative juice substitution with water or early harvest wine has the potential to produce lower alcohol wines without critically modifying colour or tannin properties and only marginally changing volatile and sensory profiles. Whether this approach is suited to producing lower alcohol wines in the absence of excessive grape ripeness remained to be determined. The current study extends on pre-fermentative approaches to alcohol management under milder grape ripening conditions and builds on an existing study with McLaren Vale Cabernet Sauvignon fruit, allowing for a direct comparison under two distinct vintage conditions.

Comparison of consecutive harvests versus blending treatments to produce lower alcohol wines from Cabernet Sauvignon grapes: Impact on wine volatile composition and sensory properties.

This study extends previous work on Cabernet Sauvignon wines of lowered alcohol concentrations produced by pre-fermentatively substituting proportions of juice from an overripe crop with "green harvest wine" or water to adjust initial sugar concentrations. Resulting wines were assessed for their volatile compositions and sensory characteristics to evaluate the suitability of this winemaking approach to managing wine alcohol concentrations in warm viticulture regions. Wines from water or green harvest wine substitution were also compared to wines of similar alcohol content produced from earlier harvested grapes.

Comparison of consecutive harvests versus blending treatments to produce lower alcohol wines from Cabernet Sauvignon grapes: Impact on polysaccharide and tannin content and composition.

A changing climate has led to winegrapes being harvested with increased sugar levels and at greater risk of berry shrivel. A suggested easy-to-adopt strategy to manage the associated rising wine alcohol levels is the pre-fermentative substitution of juice with either "green harvest wine" or water. Our study investigates the effects of this approach on Vitis vinifera L.