How to Unstick a Stuck Fermentation
Posted Nov 13th 2012 | By:
You may be new to home wine brewing or you may have been making your own wine for some time with no problems at all and suddenly, you are confronted with a must which has stopped bubbling too early. This is known as stuck fermentation and it results when the yeast becomes inactive. Even though yeast is considered to be the most crucial ingredient in your wine making, don't worry about this problem it's quite rare for a yeast to be completely dead and this home wine brewing issue can usually be remedied.
A list of stuck fermentation problems can be found below together with their various solutions for each solution, allow three days for fermentation to restart.
The temperature is not quite right (i.e. too hot or too cold).
Make sure the yeast is added to the nucleus at the right temperature (as shown on the yeast packet). If the water is too hot, the yeast will die and you will have to start this part of the home wine brewing process over again.
Additionally, make sure that you place your fermentation vessel in a room set to a temperature of about 70F. If your vessel is in a room too hot or too cold, then either adjust the room temperature to suit or move the fermentation vessel to a room more suitable. Give the must time to restart.
The must does not have enough sugar to turn it into alcohol.
The correct amount of sugar is vital during home wine brewing and taking regular hydrometer readings is crucial. Calculate how much sugar to add based on the alcohol content required. If necessary, add more sugar and wait for fermentation to start.
Alternatively, if your must contains too much sugar, then dilute with water and wait for fermentation to start.
There is too much carbon dioxide in the must.
The best way to solve this as part of your home wine brewing process is to open the fermentation vessel, stir the must and reseal the vessel. Wait for fermentation to start.
The yeast does not have enough oxygen available to keep fermentation going.
Make sure to use water which has not been distilled. Distilling removes oxygen from the water and the yeast needs this oxygen to do its job properly. Try racking your wine into another container, give it a good stir and then rack it back to your original fermentation vessel. Stir once more and then seal. Wait for fermentation to start.
The must contains an insufficient amount of nutrients.
Add teaspoon of yeast nutrient and teaspoon of yeast energizer per gallon of wine. Reseal and wait for fermentation to start.
The next time your wine yeast stops working, you now have the knowledge to fix it. Even if this particular wine in your home wine brewing batch does not come out perfectly, your fact-finding arsenal will be well and truly armed for the next batch.
Cynthia Cosco is the founder of Passaggio Wines and is an award-winning winemaker educated in Napa. Through maketastywine.com she offers 12 month support on email and Skype to a book on making wine at home. To get a free preview of the book click here.
and Tagged with