Saturday, October 17, 2009

Young Oak Vineyards: Volume 43: Stuck Fermentation!!

Hi all:

My initial fermentation has been taking more time than expected. In fact, I have had the "Must" (grape skins & juice) fermenting for almost two weeks now, which should have only been about a week. According to:

Wine yeast is most happy when:

  • It's not too hot, and not too cold
  • There's lots of food to eat
  • No killer agents are present
  • They live in sanitary conditions
  • Oxygen is available (to kick off fermentation)
To make sure oxygen is available, I have been punching down the "Cap", the layer of floating grape skins, that forms on the top of the "Must". I have been trying to do this 2 or 3 times a day, once early in the morning before school (my work), late in the afternoon after school (my work) and once at bedtime. This circulates the juice, grape pulp & skins which should give more food to the yeast.

There is the possibility that the fermentation is "Stuck", which does not happen very often, but if it is going to happen, it will happen to me & I cannot rule it out. I have tried my best to be sanitary & there is not much I can do about past contamination, so that just leaves the temperature variable.

The temperature of my bubbling brew has not exceeded 68 degrees Fahrenheit (that's 20 degrees Celsius for you metric folk), which maybe is a little on the low side. It is suggested that one might warm the "Must" to 70-75 degrees to "Un-Stuck" a "Stuck" fermentation, which I hope will naturally happen with our bout of warmer weather we have had here for the last two or three days. I'll let you know how things progress over the weekend.

With alcoholic wishes & vinegar nightmares,


  1. John

    I had this problem once a couple years ago. In VA its not unusual to have 30 degree temps this time of year. Some folks an hour North of us had snow last night. I generally only work in small batches, so I wrapped a heating pad around my 6 gallon primary fermentation vat and attached it with packaging tape. I was able to bring the must up from around 65 degrees to 73 degrees. I hope you get bubbling again soon!


  2. Hey thanks HB!

    That was my next move. October is a mixed month here in California. Some years and somedays are just about the best time of the year, 70-80 degrees with beautiful weather. Last Saturday was one of those days, but then we had a storm front move in and Sunday temps plummeted and today it rain on and off all day. I used to work for a company that made sheet heaters, so I am foraging through my garage (rhymes with garbage!) looking for something to heat up my fermentation tank.