Wine Industry Newsletter

Winemakers’ trial forum

Wine Makers Trial Forum

Following the success of last year’s inaugural event, the Department of Agriculture and Food, Western Australia (DAFWA) again provided a forum for WA winemakers to come together and share different viticultural and winemaking trials.

Last year’s forum featured exclusively red wines, so this year’s theme focussed on white wine production.

With a full venue of 24 winemakers from the Geographe, Margaret River and Great Southern wine regions, nine trials were presented featuring Chardonnay, Sauvignon Blanc, Semillon and Fiano. The group tasted the wines ‘blind’, followed by a group discussion on differences and preferences of the various treatments.

Trials included:

  • A comparison of six different Chardonnay clones
  • Sauvignon Blanc cold settled vs floatation
  • Sauvignon Blanc fermented on skins in oak vs plastic vessels
  • Comparing Chardonnay fermented with high and low solids
  • Impact of nutrient addition to Chardonnay wild ferment
  • Comparing Chardonnay wild ferment with non S.cerevisiae
  • Impact of timing of sulphur dioxide addition to Chardonnay barrels
  • Fiano – stainless steel vs barrel fermented

Chardonnay clones
This trial featured six Chardonnay clones produced from a vineyard in Mount Barker, including French Bernard clones 76, 95, 96, 277; Californian I10V1 and our local Gingin clone. 45% of the group ranked the 277 clone as the most preferred, followed by the 95 and Gingin clones who were equally preferred by 20% of the group. Those who preferred 277 described the wine as having greater balance and generosity than the others. Clone 76 was the least preferred due to its high acidity which some thought may make it more suitable for sparkling wine production.

Sauvignon Blanc cold settled vs floatation
Comparing two commercial grade Sauvignon Blancs which had their respective juice clarified by conventional cold settling and floatation. Floatation was clearly preferred at 65% as the wine showed to be brighter and more vibrant than the cold settled version. Discussion on experiences using floatation to clarify juices were positive as the quality of the wine was not compromised, the speed of which juice can be clarified, and the ratio of cost versus return from the necessary equipment.

Semillon cold settled vs floatation
Following from the previous trial with Sauvignon Blanc, this was an identical trial featuring Semillon. Preferences between the wines were closer but floatation was still the preferred treatment at 52%. Again the discussion was that floatation provides a cost effective opportunity to improve efficiencies in refrigeration, settling times and lees recovery without detriment to quality.

Sauvignon Blanc skins ferment 
A parcel of Sauvignon Blanc was fermented on skins, half of which was in a plastic vessel and the other half in an oak vat. The preference was given to the plastic vessel parcel as the oak was perhaps too apparent on the wine. The panel discussed the role of skins in white wine fermentation, ‘natural’ winemaking and how this treatment could provide an interesting blending component when making a more conventional style.

Chardonnay solid levels
Two Chardonnay’s fermented with juice turbidity’s of 68 and 327 NTU were compared; the panel was split in terms of preference as both wines were described as high quality examples of the variety. Most winemakers indicated they preferred fermenting Chardonnay with higher solids but this trial interestingly showed that a low turbidity juice can also produce quality wines of a slightly different style. This trial demonstrated solids can contribute to stylistic differences but not necessarily quality differences.

Chardonnay nutrient regime
Two parcels of Chardonnay were wild fermented, one with a commercial yeast nutrient added and one with no supplement. The majority of the panel preferred the wine with no addition. Wild ferments can be at times be difficult to complete to sugar dryness but winemakers commented that this year ferments were strong and issues were rare.

Chardonnay yeast trial
A split parcel of Chardonnay was inoculated with a Torulaspora Delbrueckii yeast strain while the other was left to a wild ferment. This approach was aimed to replicate the profile of a wild ferment by using a commercial yeast preparation. Differences were noted between the wines and the wild ferment was preferred.

Chardonnay sulphur dioxide timing trial
Chardonnay barrels received sulphur dioxide immediately after fermentation and one month post-fermentation. At 74% the panel preferred the later addition which was described as having greater depth and complexity. But again the preference scores were based on style rather than quality as both wines were good examples of regional Chardonnay.

There are not many plantings of this Italian white variety in Western Australia so the panel found these wines of great interest. The two wines shown were a stainless steel and barrel fermented versions of the same parcel of fruit. The two wines were very different in style but both showed varietal traits. The barrel fermented wine was the preferred of the two at 65%, but overall the panel found the two wines would complement each other in a blend.

DAFWA intends to hold this forum on a regular basis to provide WA winemakers with the opportunity to share experiences and promote innovative approaches to improving production efficiencies and wine quality.