Thank you Andrew Copeland for contributing to last week's discussion on Barolo Soils!
This week: New Zealand Sauvignon Blanc
Summarize the cause(s) for the intense, pungent aromatics found in many (not all) New Zealand Sauvignon Blancs.
1/ A major cause for the intense aromas of SB is the fact that the grape itself contains a high level of methoxypyrazine.
2/ Methoxypyrazine dissipates as grapes ripen, so the riper the fruit, the less pungent the aroma. In New Zealnd, the fruit is usually picked at a lower brix (about 22*)than its counterpart in say California (say 24-25*). This picking at a lower ripeness showcases the aromatics.
3/ the climate in NZ being generally cooler as well, the natural acidity in the grape would be naturally higher ( compare 9 grams of total acidity on average in Marlborough to 6 grams of TA in Sonoma Valley). This high level of acidity would highlight the chacacters of pyrazine i.e. pungent green aromas even further
4/ screw caps generally used in NZ will give a more reductive character to the wine i.e. retain more sulphur compounds which would make fresh fruity and sharp aromas more apparent.
Additionally, yeast selection plays a key role in converting thiol-precursors into volatile thiols, accenting the typical passionfruit/grapefruit style that New Zealand Sauvignon Blanc is know for.
Well, also the crop levels in NZ vis a vis Sancerre are different. Despite having more sunshine and warmth in NZ, they are not able to ripen the crop to the extent that could reduce pyrazine. The soil in NZ is more fertile with higher clay content while Sancerre is far more limestone to give same crop levels.
To add on to Kamal's comment, crop levels are different yes. They also crop super high, which is part of how much ripeness they get. Driving through Marlborough is like driving through a garden - TONS of leafy vegetation. The vineyards look nearly like the hedges bordering the property of someone that really wants their privacy. This is a huge contributor to pyrazine levels as well.
To add on using the conversation from a few weeks back, fining also plays a role. A winemaker is able to use a protein based fining agent and fine for aromas.
I had also read that, as dustin mentions, the yeasts that marlborough has selected punch up the style of the region and was a conscientious effort from producers to embrace a regional style.
I had additionally always read that the New Zealand Sauvignon Blancs benefited from the hole in the ozone above new zealand that allowed more UV light in and consequently affected the flavor compounds in the skins giving that higher signature aromatics. evidently the UV affects all plants there I was just told from my lumber guy that the pine trees in New Zealand have the highest record growth rates and are producing a lot of the worlds framing lumber due to this speed.
Thank you, everyone! I would add that the type (machine) of harvesting common in New Zealand lends itself to this intensity. Listen to our podcast on Wine Chemistry for more information!