The grapes are in, the fermentations are going… Now what can you do to get the best out of your 2011 wines?

With the 2011 grape harvest finally drawing to a close, the winemaker’s work is yet to be finished.

As a consequence of the late growing season and the high prevalence of Botrytis infection in the vineyard, many wines are presenting challenges.

Stuck or sluggish fermentations: Although alcohol levels are not significantly high in 2011, the number of stuck or sluggish fermentations is particularly high. The unbalanced microflora on grapes, mainly due to Botrytis infection, has led to more challenging fermentation conditions. Some juices have presented abnormal levels of volatile acidity right at the start. In case of stuck fermentations, we recommend performing a Fermentation Assessment Panel (Panel 9), to have a snapshot of the wine and allow better insight into the cause of the problems. If lactic acid bacteria populations are high, treatment with Lysozyme (Enartis Zym Lyso) before beginning the re-start protocol is recommended to prevent these bacteria from consuming sugars and producing VA. If stuck fermentations were due mainly to toxicity coming from grapes (late treatment of the vineyard, inhibitor compounds like short chain fatty acids, etc), treatment with yeast hulls or micronized cellulose (Celferm) can be highly beneficial. The use of EZ Ferm 44, a highly fructophilic yeast, will help ensure complete consumption of residual sugars, in particular fructose.

Wines with high acidity: The acidity levels on 2011 wines prior to malolactic fermentation (MLF) are higher than usual. If malic acid content is higher than normal, one can expect a more significant drop in total acidity, and a greater increase in pH post MLF. The use of Enartis ML Silver freeze-dried bacteria, even in challenging conditions with high levels of malic acid, will limit the production of diacetyl, enhance fruit notes and reduce herbaceous characters while ensuring a complete MLF.
Before conducting MLF in red wines, it is important to ensure good color stability by promoting the formation of stable pigments. The use of Enartis Tan Fermcolor or Enartis Tan Fruitan at pressing will be beneficial in promoting the combination of high quantities of free anthocyanins with soft tannins via acetaldehyde bridges allowing better color preservation prior to MLF. Apart from the effect on color, the use of these tannins after pressing will contribute to increased structure and mouthfeel.

Unbalanced/diluted wines: Many wines produced from grapes harvested after the rains present weaker structure than desired. The use of Enartis Tan Rich after pressing will help increase structure and balance. The use of Surli One prior to MLF will increase wine colloids by providing high quantities of mannoproteins enhancing volume and roundness as well as promoting color stability. When used at this stage, Surli One also facilitates MLF.

Clarification and Filterability: Glucan testing will give an early indication of the presence of these compounds, which can affect clarification and filterability of wines even in low concentrations. Glucan analysis performed at Enartis Vinquiry on wines from this harvest, has shown the presence of glucans in excess of 3 mg/L. Studies have found that at concentrations as low as 3 mg/L, glucans can cause serious filterability problems. Enartis Vinquiry strongly recommends all wines produced from grapes subjected to Botrytis infection in the vineyard and destined for sterile filtration be tested for the presence of glucans. If wines test positive for glucans, the use Enartis Zym Elevage, a β-glucanase enzyme, will promote the elimination of glucans and help prevent membrane filter fouling.