Depending on where your vineyards are located, Pennsylvania (PA) is seeing dramatic climatic differences during the 2017 growing season. The weather associated with the growing season ultimately influences grape quality for the current year’s vintage.
The northwestern part of Pennsylvania (Erie County) has experienced a hot and dry growing season through September 2017. Andy Muza, Penn State Extension, indicated that Northwestern PA is about 2 weeks ahead of the average harvest schedule for many wine grape varieties.
In contrast, Southeastern PA (Philadelphia County) has had a cooler and wetter growing season compared to the upper Northwest. In fact, it feels like these few weeks of September have finally welcomed the summer heat. In the Greater Philadelphia area, the beginning of September had daily precipitation and high humidity Hurricane Irma moved its way into the continental U.S. Nonetheless, since mid-September, the days have progressed from humid into relatively dry, hot and breezy weather growers like to see before harvest! This is ample hanging time for many varieties.
Below indicates a few situations winemakers may experience in incoming fruit, depending on their seasonal growing conditions.
This is not necessarily a bad problem, but it can throw growers and winemakers off track logistically. Picking decisions are often based on a number of factors including availability, logistics associated with other harvests and deliveries, and the pending rainfall. However, remember that grape ripeness and flavor should be a consideration as well.
For those regions experiencing ripeness ahead of schedule, I recommend going out daily to track the taste of your berries and focus on key sensory characteristics that you are looking for in the wine.
If you are focusing on flavor, be aware that many flavor compounds “ripen” after the sugar level (Brix) has plateaued. In a process coined, engustment (Coombe and McCarthy, 1997), flavor tends to be most intense after the “ideal” 21°Brix point. This may suggest that if weather conditions are favorable, holding the grapes on the vine until they reach flavor maturity may make a more expressive wine. Often times, the moment of “flavor pop” is only a few days after reaching 21-23°Brix.
Monitoring acid is a good practice here, as well. Take 100-200 berry samples using a good sampling procedure to assess changes in acidity. With a greater number of reports of vineyards and wineries experiencing high potassium problems, having routine data points that assess acid (both pH and TA) give winemakers a better indication of grape quality before it comes into the winery.
While high potassium winemaking strategies are not available here yet, we’re happy to work with those that may be experiencing that problem.
Incidence of Rot
In tight-clustered varieties like Pinot Grigio, Pinot Noir, Riesling, and even Vidal Blanc, rot can be prevalent from sites that may have experienced cooler, wetter or more humid growing conditions. At 20% rot or under, visually assessed, most varieties can create a decent wine, but may require more attention to processing details.
Rot strategies will differ between white and red processing. In general, always consider sorting out as much rot as possible to avoid as much extraction as possible of rot-induced byproducts and off-flavors. If you are dealing with Botrytis, ß-glucanase enzyme to help break down glucan molecules created by the rot as glucan accumulation can lead to filtration problems near the end of production.
For whites and rosés, avoid skin contact as much as possible. Removing gross lees immediately after primary fermentation is complete can help avoid further extraction of rot components.
For reds, it may be advantageous to use a yeast strain that will complete fermentation quickly to avoid excessive exposure with the rot. As always, regardless of variety, employee the appropriate yeast nutrition steps.
There are many products on the market like tannins and polysaccharides that may help stabilize or improve mouthfeel characteristics associated with wines produced by rotted fruit.
Make sure to use sulfur dioxide appropriately during production. The incidence of any rot can obviously indicate the presence of other spoilage microorganisms.
Refer to the Articles page for more specific information on dealing with Botrytis during the winemaking process.
Lack of Varietal Maturity: Green Flavors
Cooler summers or growing seasons, as well as more regular rainfall, can lead to higher incidences of methoxypyrazine (MP) concentrations in the fruit at harvest, or other green compounds, especially in varieties like Cabernet Sauvignon, Cabernet Franc, Merlot, Sauvignon Blanc, Semillon and Carmenère.
While it is best to work with MPs from a viticultural standpoint, some years, winemakers are faced with the inevitable of handling fruit that contains higher concentrations of MPs. Below are some general recommendations winemakers can use to help minimize the extraction of green characters during the winemaking process:
- Documenting flavor changes in the vineyard through routine berry sampling techniques.
- Avoid as much green matter as possible during crush/destemming and pressing.
- Use a yeast strain that can help enhance fruit characteristics that may compete with green flavors.
- Always apply appropriate yeast nutrition strategies.
- Depending on the style of wine you are producing, co-fermentations with multiple varieties may help improve flavor and mouthfeel of less mature varieties.
- There is some evidence that co-inoculation strategies, in which primary and malolactic fermentations progress at the same time, can help improve fruitiness of red wine varieties.
- Consider product additions that may help minimize the sensory impact of green flavors.
- Maximize the use of blending to improve wines produced from immature fruit.
For some varieties, the green flavor may not be undesirable, and it is worth noting that not all green flavors are created by MPs. This indicates that there are a number of alterations in production that can be integrated to help work with immature fruit.
Whatever the 2017 season may bring to you, there is always help available if you need it. If you’re struggling with production decisions, or trying to avoid future problems in making the best possible wine, please don’t hesitate to contact [email protected] to discover what Denise Gardner Winemaking can help you with today.