Posts Tagged ‘university of california davis’





UC Davis researchers create Brettanomyces aroma wheel

As much as it’s reviled, Brettanomyces still has its supporters in those who think a little bit of barnyard or wet dog imparts a distinct identity to their wines.


The clean, modern winemaking practices of the sort espoused by the University of California, Davis, have put Brett squarely in the menace category. Dr. Linda Bisson, who studies the metabolic pathways of yeast at UC Davis, however, likened Brett to a color in an artist’s palette.


Granted, it might be a color similar to a brash, fluorescent green that is best used sparingly, she told Wines & Vines.


Bisson and UC Davis Viticulture & Enology Department staff member Lucy Joseph released a Brett aroma wheel around the start of the year. The wheel is the result of a study the two performed on a collection of 83 Brett strains, of which 17 were identified as positive and five as negative by a sensory panel.


Aroma Wheel.

Aroma Wheel.



Strains that garnered a negative reaction were those that generated more aromas in the rotten and putrid category, as opposed to positive characteristics such as floral and spicy. Some strains had no sensory impact even though the Brett population grew in the wine. Certain strains also exhibited a correlation of descriptors such as earthy and putrid or Band-Aid and soy.


The positive strains did add something good to the wine rather than just not befouling it, Bisson said. The finding would appear to underscore the essence of the Brett debate between those disgusted by its flaws versus others intrigued by its complexities.

Read on…

The magical world of a barrel cellar.

The magical world of a barrel cellar.


I have often wondered why winemakers put their wines, white or red, in oak barrels and age them for sometimes months at a time.

The University of California Davis recently conducted a seminar on oak management and wine sensory issues. It looked at the use of oak barrels and oak adjuvants such as oak staves and oak powder with regard to how the oak may affect the wine’s chemical composition, aroma and flavors.

To me, the aroma of a wine is the “smell” of the specific grape varietal. But this very sensitive element can be easily influenced by the winemaking techniques and the use of oak barrels.

One obvious question is: why were oak barrels chosen to store wine in the beginning? The barrel is a perfect container to age wine in and is easily moved around manually. The answer seems to be related to the fact that oak barrels do not leak if properly coopered.

One of the most intriguing questions that was discussed at this seminar was what would have been the impact on wine tastes and wine’s appeal if a different tree had been chosen for barrel production. Has the effects of the oak barrel basically defined our tastes for different styles of wine?

Most European oak barrels are made from the Quercus petrea or Quercus robur while Quercus alba or the white oak is the main species used in American oak barrels. Today a good French oak barrel sells for around $1,000 a barrel and many of these barrels can only be used for several years before they lose their ability to enhance the flavors of the wine.

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