Ohio Grape-Wine Electronic Newsletter

Editor: Imed Dami, PhD
Assistant Professor and Extension Viticulture Specialist
Department of Horticulture and Crop Science
Ohio Agricultural Research and Development Center
1680 Madison Avenue
Wooster, OH 44691-4096
Phone: (330)-263-3882
Fax: (330)-263-3887
E-mail: dami.1@osu.edu
www.oardc.ohio-state.edu/grapeweb/

17 September 2007

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Content:

2008 OGWC
Harvest Update
MALB Update
New Small Fruit Specialist
Economic Impact Survey
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2008 Ohio Grape & Wine Conference – Mark your Calendar!

The Ohio Grape & Wine Conference will be held on 11-12 February at the Shisler Conference Center at OARDC in Wooster, OH. Please mark your calendar. More information will be forthcoming.

Grape Harvest Update
By Imed Dami, PhD
Dept. HCS-OARDC

Grape harvest has started with early varieties and in warm regions of Ohio. The 2007 harvest season is reminiscent of 2005. It has been warmer than normal and the accumulation of growing degree days has been higher than normal. As a result, grapes are picked 5 to 15 days earlier than last year. The following GDD are collected at OARDC in Wooster in the past 3 years.

Location                       Year                             GDD (1 April -14 Sept)

Wooster                       2005                            2648
                                    2006                            2483
                                    2007                            2622

The warmer temperature has also led to a rapid accumulation of sugars. We have seen high Brix, but pH (low) and TA (high) did not keep up the pace. At the OARDC research vineyard in Wooster, Brix and TA are generally higher and pH lower than normal. The same phenomenon was observed in 2005. Seasons with higher than normal GDD produced high quality reds due to extended ripening period which allows the development of desirable flavors. With sunny warm weather in the forecast, it is best to let the fruit hang to allow pH to increase and TA to drop and the varietal character to develop; unless the fruit begins to breakdown.

There is more information on harvest considerations that I encourage you to read in the “Midwest Grape Production Guide” – Chapter Harvesting and Marketing: http://ohioline.osu.edu/b919/0016.html. I have also attached the article below by Dr. Joe Fiola, Small Fruit Specialist, University of Maryland, from a previous issue of OGEN. You may find it useful when deciding when to pick grapes especially the red varieties.

It is critical to properly monitor and assess the fruit characteristics and maturity to make the appropriate management, harvesting, and winemaking decisions to produce the best quality grapes and wine possible. The following is a set of guidelines that will help you optimize fruit quality and give you the opportunity to make the best possible wine.

The critical principals here are that high quality wine is the confluence of fruit derived flavor and aroma components and for red grapes also the reduction of immature tannins.
These do not necessarily correspond to desired sugar and acid ranges.
The highest priority needs to be the quality and quantity of varietal aroma/flavor in the fruit.

        - Simply stated, to obtain a desired characteristic aroma or flavor in the wine, it must be present in the grapes at the time           of harvest!
        -By regular, continuous sampling you will learn through experience the succession of aromas, flavors and textures that each     variety goes through.
        - Depending on the degree of ripeness red grape characteristics can range from green and herbaceous to fruity and jammy.
        - Therefore the individual sampling must be diligent to monitor for that aroma and/or flavor in the sample.

The next highest priority, especially for red wines, is the texture of the grape tannins in skin and the seed.

        - These quality and quantity of the tannins determine the structure, body, astringency, bitterness, dryness, and color intensity        of the wine. Mature tannins are critical to the production of quality red wines.
        - The degree of ripeness and polymerization of the tannins will determine the astringency and mouth feel of your wine.
        - This can range from the undesirable, hard and course tannins of immature grapes, through to the desirable, supple and silky   profile of mature grapes.

Procedure:

        - Select a few random grapes and place them in you mouth.
        - Without macerating the skins, gently press the juice out of the berries and assess the juice for sweetness (front of tongue) and acid (back sides of your tongue). With experience (and comparison against numbers from lab samples) you will be able       to reasonably "guesstimate" the Brix and TA level of the grapes.
        - Next gently separate the seeds for the skins and spit into your hand. The color of the seeds gives you a clue to the level of        ripeness. Green seeds are immature, green to tan and tan to brown seeds is maturing, and brown seeds are mature. Ripe         seed tannins are desirable as they are less easily extracted and more supple on the palette.
        - Finally macerate the remaining skins and press them in your cheeks to assess the ripeness of the skin tannins. You will be   able to feel the astringency (pucker) of the skins. The less intense the astringency the more ripe the grapes.
        - A good way to practice is to first sample an early grape variety such as Merlot and then immediately go to a later variety    such as Cab Sauvignon, and you will feel the difference in the astringency and ripeness.

Of course, other factors must still be considered, such as the total acidity and pH

        - Generally you would like to harvest white grapes in the 3.2-3.4 pH range and reds in the 3.4-3.5 range, as long as the varietal       character is appropriate as described above. Remember the enologist can do a good job adjusting acidity but it almost impossible to increase variety character in the wine.
        - Brix or sugar level is good to follow on a relative scale but levels can greatly vary from vintage to vintage.
        - In some years the grapes will be ripe and have great varietal character at 20 Brix and another year they may still not have   ripe varietal character at 23 Brix.

Disease/Rot - Monitor to see if the grapes are deteriorating due to fruit rots or berry softening.
Look at the short and long range forecast.

- If it looks good and the grapes have the ability to ripen further, then there may be a benefit to letting them hang a bit longer.
- If the tropical storm is on the way when grapes are close to optimal ripeness, it is more desirable to harvest before a significant rainfall than to wait until after the rain and allow them to build up the sugar again afterwards.

Update on the Multicolored Asian Lady Beetle (MALB)
By Roger Williams and Dan Fickle, Entomology/OARDC/OSU

We are currently monitoring vineyards across the northern tier of Ohio for the presence of this pest. Adults began showing up the first week of September on yellow sticky traps placed around the perimeter of the vineyards. Numbers were low and further examination of the ripening fruit did not indicate beetle contamination at that time. However, in subsequent days now we have begun to experience cooler temperatures which are the triggering mechanism for beetle migration. It has been reported that it requires approximately 200 hrs of chilling temperatures (temperatures below 60 degrees F.) to trigger beetle movement. With the onset of cooler nights scouting for MALB should be conducted weekly from now to harvest. Remember it only takes as few as 12 beetles in a lug of grapes to cause contamination of the juice. Inspect your clusters prior to harvest, at harvest and again prior to processing. This will help to prevent what could be a costly contamination problem at crush. We currently have three products that have demonstrated good efficacy against MALB and have minimal harvest restrictions, Provado (0 day), Venom (1 day) and Baythroid (3 day). Consult your product label for recommendations and rates. The 2007 Midwest Commercial Small Fruit and Grape Spray Guide may be viewed on line at www.hort.purdue.edu/hort/ext/extpubs.shtml.

New OSU Small Fruit Specialist
By Maurus Brown, PhD
OSU South Centers, Piketon

Brown, a native of Illinois, began his career at Ohio State University on June 1, 1997 after completing a Ph.D. in plant breeding and genetics at the University of Arkansas, Fayetteville. His dissertation research focused on downy mildew resistance in table grapes. He was originally stationed at the OARDC, Wooster working with the Ohio Grape and Wine Industry in the capacity of Extension Associate Viticulturist. In September 1999, Brown accepted the position of OSU Extension Educator in Richland County, with a specialization in small fruit crops.

Brown was promoted to the position of Small Fruit Crops Specialist at OSU South Centers, Piketon on June 1, 2007. His research involves field and lab analysis on grapes, blueberries, blackberries, raspberries, strawberries and currants. Educational programs are provided for small fruit production, marketing, tourism, fresh fruit consumption, nutraceutical benefits and growing fruit in the home landscape. Brown is focusing on various aspects of small fruit research and welcomes your input on topics that you feel would be import to address. He continues to collaborate with colleagues at OSU and other land grant universities to publish Extension bulletins that are grower focused on production, marketing and tourism related issues.

OSU Extension Conducting Statewide Economic Impact Study
By David Marrison, Assistant Professor
OSU Extension-Ashtabula County

OSU Extension is currently coordinating an economic impact study of the Ohio Grape and Wine Industry. This goal of this research project is to capture the indirect and direct economic impact that the grape and wine industry has on Ohio's economy. The data collected will be used by decision makers at all levels of government, from local to federal. The results of this study will help build credibility for the Ohio industry nationally and support investment in our industry by the State of Ohio and others. This survey was mailed to all vineyard and winery managers at the end of July. If producers have misplaced their survey, they can contact the Ashtabula County Extension office at 400-576-9008 for another copy.
This project is being conducted in conjunction with the Lake County Soil & Water Conservation District and Ohio Wine Producers Association with support from the Ohio Grape Industries Committee and the Cleveland Foundation.
Working together, we will be able to determine the true economic impact of the Ohio grape and wine industry. Thank you to all who are participating in this study.