Fed Ag station forecast is upbeat

Pully, vines ready for the harvest. Click on image to view larger

GENEVA, SWITZERLAND / AMONG THE VINES – Cross your fingers that the weather is friendly to Swiss grapes in the next two to four weeks, as the harvest is pulled in: so far, so good for an excellent vintage, is the verdict of the Changins Federal Agriculture Research Station near Nyon.

The harvest is indeed starting later than we’re used to, but this has much to do with the grapes harvested earlier than usual for the past 20 years, according to a study of Chasselas grapes in Pully, next to Lausanne.

The 89-year study of the growing cycle until grapes have enough sugar for harvesting is the oldest in the country. Grapes need a good balance between acidity and sugar for quality wines.

Switzerland and most German-speaking grape areas use the Oeschlé scale while other countries use the Baumé or Brix scales.

Slow start for 2013 grapes, now caught up

The Pully study shows that this year’s grapes are in line with the average date for ripeness over the past nine decades.

By the time Yens, near Morges, began its vendange/harvest festival 6 October 2012, the grapes were all in

The year started off cold and miserable but thankfully for wine lovers September was a great month for grapes. Although at the start of September the grapes were 15 days late compared to the average growing cycle, by 20 September they had nearly caught up, and three days later they were right on track to be harvested.

The measures are for Chasselas grapes growing in Pully, and in other parts of the country, at different altitudes and for different grape varieties, the harvest tale varies somewhat.

Grapevine flowering (source: Changins-Waedenswil research station)

Pully’s grape-growing records nevertheless provide a wonderful measuring stick for key stages in a vine’s annual cycle:

• the start of new growth, called débourrement in French
• the start and end dates for flowering, the floraison
• the start of the maturing period, the véraison.

The Pully station watches each stage of maturing period closely, and uses 20 September as a base date for comparing the level of sugar in the grapes.

The rundown of the 2013 wine grape season

March – cold enough for the start of vegetation to be slowed down: registered 23 April, exactly 10 days later than the 1925-2013 average.

April – relatively normal.

Chasselas, Switzerland’s emblematic white wine grape

May – cold and humid (2.5-3C below average), almost completely blocking the vines’ growth.

June – 15 warm days followed rapidly by marked cold for the last 10 days of the month.

Flowering occured 1 July, whereas the 89-year average date was 15 June and for the past 20 years it has been 12 June.

July and August – “splendid” weather, according to Changins, with Meteoswiss noting that it was the 7th warmest July since national temperature measurements began in 1864.

Chasselas is considered one of the world’s finest terroir grapes, for its ability to reflect in its wines the soil, weather, sun exposure, altitude and micro-climate. Its birthplace is the Lake Geneva area, DNA research has shown.

Flowering that began 1 July finished 8 July, an unusually short period, and the 15-day lag was shortened to nine days.

Maturing process: started 18 August, and the lag time fell to just five days compared to the 89-year averag, or 11 days compared to that for the past 20 years. Noteworthy, at this point 2013 grape development was similar to that of four excellent vintages: 1942, 1961, 1967 and 1969.

September – a beautiful month for grapes, from start to finish. The sugar in the grapes was measured 20 September at 65.2 °Oechslé compared to 68.8 °Oechslé for the 1925-2013 average, and on 23 September it reached that level.

One-quarter of the grapes for the past 89 vintages have had less sugar than the 2013 vintage on 20 September, and for Changins, this year does not compare at all to late years where the must (grape juice) hadn’t even reached 55 °Oechslé or the disastrous years of 1939, 1965 and 1980, where they stalled at 50°Oechslé.

Chart of wine grape growing season, 1925-2013, for Chasselas in Pully, canton Vaud

 

Pully study, 1925-2013 Chasselas grape season (source: Changins-Waedenswil Swiss Federal Research Station)