Botrytis cinerea, otherwise known as ‘Noble Rot’, can be a favourable fungus infection, when harnessed to product dessert style wine.
Grapes become infected and then dehydrate, resulting in a natural sugar level concentration much higher than would usually be present in normal grape ripening.
The Botrytis spores also deliver components into the grapes that change the character of the resultant wine, increasing complexity and expression beyond varietal notes into a realm reminiscent of honey, apricots and marmalade.
“To produce a Botrytised wine takes a lot of planning and meticulous work in the vineyard,” says our Vineyard Manager Cameron Joyce.
Not all grapes are created equal, and not all grapes are suitable for wine production influenced by Botrytis cinerea.
The ideal grape is one with a thin skin that also has tight grape bunches. When the skin is thin it facilitates the fungus spore piercing the skin to access the sugars inside. The tighter the bunches, the faster the fungus can spread as the berries are in direct contact with their neighbours, greatly assisting the reproduction of the spores throughout the bunch.
Historically the most ideal grapes for Botrytis cinerea are Semillon, Sauvignon Blanc and Muscadelle in the Sauternes and Barsac appellations of Bordeaux; Riesling for Trockenbeerenauslese in Germany; Chenin Blanc in the Loire Valley and Furmint for Tokaji production in Hungary.
“Grapes that are allocated for Botrytis production are managed very differently to our other grapes, even of the same variety, that are destined for our Estate wines,” says Joyce.
In the vineyard, Botrytis cinerea requires the perfect combination of humidity and warmth for the fungus to take hold and infect the desired parcel of allocated grapes correctly and evenly. The Yarra Valley is generally too cool a region to consistently and reliably achieve this infection year-on-year so it is a rarity for the viticultural stars to align and allow us the luxury of producing this hedonistic wine style.
“In order to promote Botrytis spore development and proliferation in specified parcels of grapes, the aim is to maximise humidity within the grapevine canopy,” says Joyce.
“This differs from our general grape production where we are trying our best to minimise humidity and promote air flow and dappled sunlight onto the developing grape bunches.”
“We rely on natural inoculation and we try to manage the conditions to promote its spread. Sometimes it works and sometimes it doesn’t, but as the Vineyard Manager I get a lot of high-fives from the winemaker when it does work.”
“It’s all about management, timing, crossing of fingers and an awful lot of luck that the season will provide the conditions necessary for success.”
The preceding 2017 vintage provided the perfect conditions to produce our inaugural Mélange Botrytis. Due to the success of this wine, we were emboldened to try again in 2018.
There was an existing spore load of Botrytis cinerea in designated rows we undertook the cultural method listed above but still required an extra few laps through the vine rows to spray extra water in order to enhance the humidity.
It was a very late and nerve-wracking season as we delicately encouraged the Botrytis to take hold and flourish, all the while trying to deflect the desirous attentions of the birds and bees from these delicious developing grapes.
Our efforts and holding of nerve paid off and we hand-harvested by suitable bunch-selection on May 16th, more than 6 weeks after we had completed the harvest on all other varieties.
2018 Mélange Botrytis