VOLATILE ACIDITY REMOVAL; SMOKE TAINT REMOVAL; SWEETSPOT TRIALS; MICROFILTRATION; BRETT (4EP/4EG) CHARCTER REDUCTION; DES REDUCTION; LEES FILTRATION; pH CORRECTION; ALCOHOL REDUCTION; ULTRAFILTRATION; TCA REMOVAL - WORKING WONDERS WITH WINE!

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Brett (4EP/4EG) Reduction Service
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BRETT (4EP AND 4EG) CHARACTER REDUCTION SERVICE

An on-site nanofiltration/adsorption service offered by VA Filtration to effectively reduce levels of 4EP and 4EG to less than threshold or as required by the winemaker.

The same machines used for VA reduction are used for brett character reduction.  Membranes are however changed when running the two different processes as a precaution against cross contamination.

 

WHAT IS BRETT?

  • ØA common organism (yeast) found in wine (predominantly red wine) identifiable by the distinctive aroma of barnyards and sweaty saddles in higher quantities.
  • ØKey molecules responsible for the aroma in order of importance are:

    4-ethyl-phenol (Band-Aid & sweaty saddles)

    Isovaleric acid (horsy aroma)

    4-ethyl-guiacol (smoky, spicy aromas)

  • ØSensory threshold for 4EP is 400 – 600 µg/l. Higher levels of 4EG (according to the AWRI) accentuate the aromas associated with 4EP.

     

HOW CAN I CONTROL BRETT?
  •  Keeping molecular sulfur levels at 0.6-0.8 ppm.
  •  Keeping barrel storage temperatures as low as possible.
  •  Sterile filtration - if a brett strain is noticed.
  •  Lower pH – Activity decreases as pH decreases.
  •  Sanitation of all equipment regularly including barrels.
 Essentially exquisite sanitation goes a long way in preventing brett.

 

CAN I REMOVE THE BRETT CHARACTERISTIC SUCCESSFULLY?

Yes.  The process is a mobile system which uses a combination of membranes and phenol adsorption material to remove the 4EP and 4EG from the wine.  Flow rates of between 480 and 800 gal/hr can be achieved with our mobile machine.

  

WHEN TO DO 4EP/4EG BRETT REDUCTION

  • Ø After the Brett yeast has been tamed.
 

HOW MUCH IS TOO MUCH?

  • Ø More than 4000 µg/l (EP) requires FOUR passes to reach < 1000 µg/l.
  • Ø Final 4EP levels of 500 µg/l – 800 µg/l seem to work well depending on the varietal.
  • Ø Each pass removes 30% of the 4EP from the wine and 20% of the 4EG.
 

WINE HANDLING AFTER 4EP/4EG REMOVAL

  •  Sterile Filtration

        Almost 100% certainty that all the brett character has been reduced.

  •  Sulfur Dioxide

        Ensure that molecular SO2 levels are kept high to prevent a recurrence.

 

 

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Last modified: 01/06/10