Enology Notes

Enology Notes #131, July 20, 2007

To: Regional Wine Producers

From: Bruce Zoecklein, Head, Enology-Grape Chemistry Group, Virginia Tech

Subject: New Edition of Winery Planning and Design CD Available; French Wine Study Tour November 25 - December 7, 2007; The VT Enology Analytical Services Laboratory Certification; Fermentable Nitrogen Analysis; Please Adjust Your Email Filters to Allow Enology Notes Through

1. New Edition of Winery Planning and Design CD Available.  Edition 13 is an expanded CD that covers additional topics. Each subject area is reviewed in a simple-to-read outline form.

The Winery Planning and Design CD, Edition 13, is available through Practical Winery and Vineyard magazine.

Email them at , or call (415) 479-5819.

For additional details, see Enology Notes #129.

2. French Wine Study Tour. A wine study tour beginning at Perpignan (Spanish border) to Nice (Italian border) is planned for November 25 to December 7, 2007.

The group will see the “vins cuits” of Banyuls, Maury and fortified Rivesaltes, experience the new terroirs in the hills of Languedoc (new blend varieties), the sandy wines of Listel, the success of Mourvedre and Viognier in the “Montagne Ste Victoire” around Aix en Provence, the new fashion for rosé wines in the rolling hills of Provence, and finish the study tour on a tiny island where the Monastery of St. Honorat is nestled (20 minutes boating from Cannes) to evaluate and discuss the Syrah of the monks, gold medal at the last “Syrah of the World" tasting. The tour will also include a day at SITEVI, the equipment show in Montpellier.

The tentative itinerary is as follows.

  • Leave the US on November 25, 2007
  • Monday through Wednesday, November 26 through 28: Banyuls, Corbieres, Fitou and West Languedoc
  • Thursday, November 29: SITEVI at Montpellier
  • Friday, November 30: Listel and Lirac, Rhône varietals
  • Saturday and Sunday, December 1 and 2: Arles en Provence
  • Monday through Wednesday, December 3 through 5: St. Victoire, Maures, Bandol, and St-Tropez
  • Thursday, December 6: St-Honorat  and Bellet
  • Friday, December 7: last day at Nice (possible trip to Monaco)

The group will fly from the USA to Perpignan (via Paris), and back from Nice to the USA.

Price for 12 days and a group of 20, including all transportation in France, all meals and hotel: 2900 Euros (single room) and 2650 Euros (shared room). This cost does not include airfare to and from France.

It is possible to participate in just one week of this tour.

This is a technical study tour open to members of the commercial grape and wine industry only. Space is limited to a maximum of 20 people on a first-come, first-serve basis.

Registration information will be posted on the Enology-Grape Chemistry Group website on or around August 6, 2007. 

For a review of the 2002 industry France trip, go to www.vtwines.info. Information regarding the trip to the Loire Valley is on my Enology Notes at www.vtwines.info, click Enology Notes Index, Loire Valley. Editor: Here is a direct link specifically for the entirety of the 2002 trip.

The following is from Ken Hurley, Virginia Tech Enology Analytical Service Laboratory Director.

3. The VT Enology Analytical Services Laboratory Certification. The Enology Analytical Services Lab is TTB certified. The certification is based on scholarship, experience, and the precise and accurate analysis of red and white wines across 14 parameters generally required for export wines. The analyses performed by our laboratory are TTB-approved methods developed by the Association of Official Analytical Chemists (AOAC), of which our laboratory is a member. The TTB Certification allows our laboratory results to be accepted by the TTB. All analyses performed at the VT Enology Analytical Services Laboratory are performed by certified chemists. For more information regarding the Enology Analytical Services Lab, see www.vtwines.info.

4. Fermentable Nitrogen Analysis. In Enology Notes #127, we reported that greater than 25% of the samples received by the Enology Analytical Services Lab exhibit aromas indicative of volatile sulfur compounds. The main group of volatile sulfur compounds, hydrogen sulfide (H2S), and thiols, like mercaptans (typically CH3SH), are normally formed during fermentation, in response to low levels of fermentable nitrogen.

The VT Enology Analytical Services Laboratory has instituted a program to encourage vineyard owners and winemakers to have their grape juice tested for yeast assimilable nitrogen. Upon request, the laboratory will supply sample bottles (containing preservatives) and grape processing bags. This allows pre-harvest berry sampling or crush-time juice sampling. Analysis of Fermentable Nitrogen, along with other juice parameters, if desired, can then be performed by the Laboratory so that recommendations for additions can be made.

Important Points:

  • Read the online article about Grape Sampling, posted at www.vtwines.info. Click Online Publications, then Maturity Evaluation for Growers.
  • Pre-harvest berry sampling should follow the guidelines in the article above, and SHOULD NOT be performed earlier than 4 days pre-harvest.
  • Sample kits will be available beginning the first week of August.
  • Results will be available no later than 24 hours after samples are received.

General procedure for Fermentable Nitrogen Analysis:

  1. Email the laboratory at requesting “Grape Processing Bags and Sample Bottles.”  Include your name, company, mailing address, and the number of sampling kits required.
  2. When the materials arrive, store them in a cool, dry place. Vineyard samples may be collected no earlier than four (4) days preharvest.
  3. Process the grapes, using a hand press or in the Grape Processing Bags.  The laboratory requires 125 mL of juice for analysis. Included in the sample bottles are preservatives designed for a 125-mL sample.
  4. Fill the sample bottle to the indicated level on the bottle. Mix the bottle thoroughly to dissolve all preservative.
  5. Ship the samples OVERNIGHT to the Enology Analytical Services Laboratory with the Analysis Request Form

Complete information regarding sampling and processing can be found on the VT Enology-Grape Chemistry Group website: Industry Pubs>Vintner’s Corner>Grape Sampling

Analysis results will be available within 24 hours after samples are received. It should be noted that the preservative in the bottle does not completely stop fermentation, it is only slowed. Delay in shipping or storage of the samples could cause rupture of the bottles.

The cost for Fermentable Nitrogen Analysis is $25 per sample.

The cost for the Juice Panel is $60 per sample (Brix, Fermentable Nitrogen, pH, Malic Acid, Titratable Acidity).

5. Please Adjust Your Email Filters to Allow Enology Notes Through. Enology Notes is emailed from Bruce Zoecklein ( ). Additionally, the email address may also need to be unblocked.

We have received many blocked email messages requiring us to respond in order to get through. We simply don't have the time to do this for the volume of mail we send out. We've also received some messages indicating Enology Notes is perceived as junk email. You must contact your system administrator to correct this.

Thank you.

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Dr. Bruce Zoecklein
Professor and Enology Specialist Head Enology-Grape Chemistry Group
Department of Food Science and Technology, Virginia Tech
Blacksburg VA 24061
Enology-Grape Chemistry Group Web address: http://www.vtwines.info/
Phone: (540) 231-5325
Fax: (540) 231-9293
Cell phone: 540-998-9025