For managing spoilage risks during the cold soak of reds
Pre-fermentation cold soaks are used to improve color and aromatics in all red varieties. Vincent Gerbeaux of the L’Institut Francais dela Vigne (IFV) in Burgundy selected Metschnikowia IFV Gaia from over 500 non-Saccharomyces isolates for use during cold soak applications, in particular on Pinot Noir. This strain is found on grape microflora and is non-fermentative but it does help with the balance of aromas. It has been found to enhance fruity characters and aromatic expression. The presence of Gaia during cold soak helps limit Kloeckera apiculata growth and acetic acid production. Kloeckera apiculata (Hanseniaspora uvarum) is known to be a high producer of acetic acid and ethyl acetate. Early inoculation allows for good implantation of Gaia 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 needs to be followed by a S. cerevisiae strain to complete alcoholic fermentation. If the temperature of yourcold soak is 10°C (50°F) or lower you may cold soak for up to 5 days before adding your Saccharomyces yeast. If the temperature of your cold soak is higher than 10°C (50°F), inoculation of your Saccharomyces yeast should be done at 2 days. Gaia is able to grow in low pH and high sugar musts as well as being able totolerate an initial SO2 addition up to 50ppm.
Rehydration of Gaia is done at 30°C (86°F) and does not require a rehydration nutrient. Slowly combine an equal amount of juice into rehydration solution to avoid cold shock. Total rehydration time should not exceed 45minutes. After cold soak, add selected Saccharaomyces cerevisiae with standard yeast rehydration protocol. Use of Gaia needs to be followed by a S. cerevisiae strain to complete alcoholic fermentation.