July 24, 2014

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Edelweiss Kabinett

Today we harvested some Edelweiss. I’ve struggled a bit on what we can do for vinification trials with this grape. For those who are unfamiliar with Edelweiss, it was originally developed as a table grape by Elmer Swenson back when he was working for the University of Minnesota. Although it is not seedless, which is a problem for the table grape market; it has some aromas and flavors similar to Concord grapes and can be used to make a nice aromatic white wine. We tend to simply refer to the grape as having a labrusca character (grapes from the species Vitis labrusca  have this distinct aroma), though in most wine circles this aroma is called “foxy” – an unfortunate term that really does nothing to describe the flavor to most people.

Early European settlers, upon eating the wild grapes that grew along the riverbanks in the Eastern US, decided they had an “animal-den” aroma and nick-named them fox grapes.  Perhaps our early ancestors were more familiar with fox aroma than most Americans are today, but apparently they were onto something. Methyl anthranilate, the compound that is most often cited as the compound responsible for the characteristic aroma of V. labrusca grapes such as Concord, is used as a flavor additive in candy to give it a “grape” aroma. However, researchers also point to another compound present in Concord and other V. labrusca grapes that has a similar ‘foxy’ or ‘grapy’ aroma:  ortho-amino acetophenone (OAP).[1] Athough present in grapes in much smaller quantities than Methyl anthranilate, humans are able to detect it at a lower threshold, thus it is believed that it may play a greater role in the distinctive foxy aroma of V. labrusca grapes.[2]  Coincidentally, OAP is also found in the scent glands of certain weasels,[3] so perhaps our early ancestors weren’t so far off in relating the aroma to an animal-den. However, perhaps due to our undying love of peanut butter and jelly sandwiches (or perhaps our failure to adopt fox-hunting as enthusiastically as our Aristocratic ancestors), Americans will almost always describe the aroma of OAP as grape-like or candied.

While the grapey aroma of Edelweiss and other V. labrusca hybrids isn’t necessarily off-putting to most people, it is also not an aroma that wine-drinkers associate with high-quality wine. It’s a candied-fruit aroma that is more reminiscent of candied strawberries, Jolly Rancher candy, or Welch’s White Grape Juice – not exactly flavors that go well with that roasted chicken dinner. However, on the patio on a hot summer day, Edelweiss wine can be quite refreshing. In fully-ripe Edelweiss, the candied fruit aromas can make for a tasty grape, but it can overpower the flavor of the wine. Thus, most people growing Edelweiss for wine production will harvest it before it reaches full ripeness to keep the wine aromas more subdued.

Here is a look at some of the harvest numbers we’ve had for Edelweiss over the past few years:

Harvest Date

Brix

Total Acidity (g/L)

pH

9/9/2002

17.8

8.68

3.16

8/30/2005

18.8

10.57

3.05

9/5/2007

17.0

7.02

3.23

9/4/2008

17.2

12.03

2.97

9/10/2009

17.4

9.62

3.1

8/25/2010

15.4

7.43

3.29

9/8/2011

18.1

8.25

3.2

Although Edelweiss isn’t a high-sugar grape to begin with (remember, it was developed as a table grape), one can see that we’ve never harvested it much higher than 18°Brix, so the potential alcohol of the wine will likely not be greater than 10% in any given year. Thus, many winemakers will add sugar to the juice in order to make a wine with a more “acceptable” table-wine level of 12-14%. In my opinion, the higher alcohol level tends to overpower much of the delicate aroma and flavor of the wine. There’s a disconnect between the fresh acidity and light flavors of a grape harvested underripe with the alcohol level of a grape that was left to soak up the sun a bit longer. There is precedent in the world for harvesting grapes early for winemaking. In German-speaking countries, wines made from early-picked grapes are given the designation ‘Kabinett.’ I’m a huge fan of Kabinett Rieslings. Often they are made in a semi-sweet fashion by stopping fermentation early – at say 7-8% alcohol. They are wonderfully delicate, easy-to-drink, and refreshing – something I admire in a well-made Edelweiss. By law, Germans harvest grapes for Kabinett wines between 17-19 brix, and they are not allowed to add any sugar. This year I intend to make a wine in that style. Our numbers this year will work perfectly: 17.7 brix, 7.8 g/L total acidity. We’ll try cool-fermenting it with high terpene releasing yeast (Laffort VL1) to see if we can enhance some of the delicate floral aromas, then we will arrest fermentation with about 1% residual sugar to keep it slightly sweet. A perfect wine for summer.

Happy Harvest!



[1] Shure, K.B. and T.E. Acree. 1995. In vivo and in vitro flavor studies of Vitis labruscana Cv. Concord. ACS Symposium Series 596, American Chemical Society, Washington. pp. 127-133

[2] Acree, T.E., E.H. Lavin, R. Nishida, and S. Wantanabe. 1990. The serendipitous discovery of ortho-amino acetophenone as the ‘foxy’ smelling component of Labruscana grapes. Chem. And Eng. News 9:80

[3] Brinck, C., S. Erlinge and M. Sandell. 1983. Anal sac secretion in mustelids: a comparison. Journal of Chemical Ecology. 9(6): 727-745