The Science Behind Grass in Your Glass

                     New Zealand's Greywache Sauv Blanc is one of the country's benchmarks

                                

This is the third in a four-part blog series on aromas and flavors in wine that are directly related to chemicals produced during the wine-making process.  Today, we’ll discuss the grassy smell and taste found in wine.  These isn't a figment of your imagination, but is a scientific fact that occurs as a direct result of chemical changes during fermentation.

Have you ever wondered why your Sauvignon Blanc (SB) is reminiscent of freshly mowed grass?  This classical grassiness taste and nose found in many SB’s is due to chemicals called aldehydes.  These compounds, released during fermentation as yeasts turn SB grape sugar into alcohol, evoke the smell of just-cut grass.  The SB grape has  the ability to produce high level of aldehydes.  The perception of grassiness is driven for the simple reason that these same chemicals are also found in grass.  Cutting grass releases these highly fragrant chemicals into the air.

The less ripe the SB grape, the higher the propensity is for aldehydes, and thus the stronger the grassy profile.  New Zealand SB’s are known for their traditional grassy notes.  Kiwi SB’s are purposely picked a little less mature for this reason, but also responsible is the moderate climate where this country’s SB grapes are grown.  The Loire Valley also is famous for SB.  As this area is fairly far north, SB often can’t ripen to its fullest degree, so Lorie wines classically also have grassy nuances.   In contrast, California SB has abundant sun and generally is picked more mature.  This translates to less intense grassy nuances.  In Cali’s warmer growing areas, SB’s actually can take on ripe tropical notes.

Next week we’ll finish this series by discussing one of the common flavors in sparkling wine which is also caused by the science during fermentation.

Kiwi Sauv Blancs

                           Sauv Blanc is the star of the show in the Marlborough wine district 

New Zealand has been historically a world leader when it comes to Sauvignon Blanc (SB) wines.  The classical Kiwi style is easily recognizable---a kind of in-your-face pungency of grass and citrus.  (One critic has even said that if you don’t like New Zealand Sauv Blancs, it’s because you were forced to mow the lawn as a kid).   

The Sauvignon Blanc grape is native to France.  The Loire Valley, known for its gigantic castles, is also famous for its SB.  In Bordeaux, the grape is mixed with Semillon to create an unctuous white Bordeaux.  But, it’s on New Zealand’s south island that the varietal morphs into something quite different from its heritage.   

Some of New Zealand’s most spectacular SBs come from the Marlborough wine region on the south island.  Producing >75% of all of New Zealand’s wines, this area’s flagship grape is SB.  Marlborough is a river valley that empties into the sea and its sandy-gravely soil makes for perfect drainage.  The low fertility of the soil also encourages concentration of flavors via lower yields.   The heavier soils produce the more herbaceous SBs, while its stonier soils left over from the river’s erosion impart more lush and tropical flavors.   Some scientists, however, think that a hole in the ozone layer over this region influences these bold fruit flavors.

                      Stony soils washed down over centuries by the river exert a strong influence

As in all wine, the weather plays a major influence.  New Zealand’s geography ensures that no vineyard is more than 80 miles from the coast.  This means maritime climates that are moderated by the sea---never too hot, but never too cold.  Such climactic factors ensure a long and steady growing season that allows grapes to ripen slowly.  Also, this allows for the development in balance between acids and sugars, one of the hallmarks of a well-crafted wine.

In my opinion the best renditions of Kiwi SBs are those that have tamed the grassy profiles to merely subtle background notes.  Dogpoint offers a well-made SB full of melon and passion fruit mixed with citrus and mineral flavors.  Often available at our local Costco for $20, it consistently delivers big in the quality/price department.  Greywacke (owned by the original winemaker at Cloudy Bay) also delivers a tremendous product in the same price range.  This one offers a superb rendition of well-integrated citrus, tropical, herbal, and mineral.  

Wine Knows will be visiting both of the above wineries on its 2020 harvest tour.  Currently we have 7 seats available:  www.WineKnowsTravel.com.