Pre-fermentation cold soaks are used to improve color and aromatics in all red varieties. Vincnt Gerbeaux of L’Institut de la Vigne (IFV) in Brugundy selected Metschnikowia IFV Gaia MF98.3 from over 500 non-Saccharomyces isolates for use during cold soak applications, in particular Pinot Noir. This strain is found on the grape microflora and is non-fermentative but it does help with the balance of aromas. It has been found to enhance the fruity characters and aromatic expression. The presence of Gaia MF98.3 during cold soaks helps limit Kloeckera apiculata growth and acetic acid production. Kloeckera apticula (Hanseniaspora uvarum) is known to be a high producer of acetic acid and ethyl acetate.
Early inoculation allows for good implantation of Gaia MF98.3 which can help control undesirable flora during cold soak. It is able to implant and multiply rapidly helping it to prevail over spoilage microorganisms . Use of Gaia MF98.3 needs to be followed by a S. cervisiae strain to complete alcoholic fermentation. If the temperature of your cold soak is 10°C (50°F), inoculation of your Saccharomyces yeast should be done at 2 days. Gaia MF98.3 is able to grow in low pH and high sugar musts as well as being able to tolerate initial SO2 addition up to 50ppm.