Green fungi during red wine fermentation

[peter.povy]

Hello,

I'm tring to make my first red wine. Now it's the second week of fermentation and when I made a small control of the wine I noticed a few, small (2-4mm), green color particles. Is this a mold contamination? Smell of the wine is fine. What should I do now?

Thank you
Peter

 

[Rice_Guy]

Your guess looks correct, green floating mass would indicate a mold. If you have a microscope it will look like filaments.

Mold requires oxygen for growth, I would filter (ex cheese cloth), and switch from an open mouth container to a carboy and the sulphite. All grape juice starts with a variety of microbial contamination. It dies off because 5% alcohol inhibits and pH inhibit and SO2 inhibits and a CO2 headspace kills it.

I should add welcome to Wine Making Talk !

 

[winemaker81]

Welcome to WMT!

Echoing @Rice_Guy's advice, add 1/4 tsp K-meta (potassium metabisulfite) per 5-6 US gallons / 19-23 liters of wine.

What is your SG (specific gravity)? When the SG is <= 0.998 and doesn't change for 3 days, the fermentation is done. At that point (or before) you want the wine out of an open container. During fermentation the yeast uses O2 for reproduction -- after that O2 is one of many enemies of your wine.

Trust your nose. If the wine smells good, it's fine.