There could be several reasons for stuck fermentation.
But, don’t panic there are many solutions for handling it.
Let’s get a few questions answered first.
#1 Cause and Solution
Did you wait 24 hours before adding yeast to must?
When you make your must, you are advised to wait 24 hrs before adding the yeast.
There is a reason why.
You have sulfites in your must. Sulfites kill bacteria AND yeast. The 24 hour period lets the sulfites kill any bacteria and have time to dissipate, thereby making your “must” ready to let the yeast convert the sugar to alcohol.
Read more about sulfites here.
#2 Cause and Solution
Was the temperature of your “must” correct?
It is important for your must to be at the proper temperature, between 70 and 80 degrees F. This allows the yeast to work properly and not produce any off flavors. If the must is too warm it will boil wildly and stop too soon.
If the must is too cool, it will not work(bubble) much. You will need to get the temperature up (wrap a blanket or use a heating pad on a very low setting if it is extremely cold).
OR perhaps use a “yeast starter”. To make a yeast starter, dissolve a tablespoon of sugar in a cup of warm water. Add your yeast package to the sugar water.
After a few hours, you will see your yeast start to bubble and multiply. Go ahead and pour this “yeast starter” into your must and you will be on your way.
#3 Cause and Solution
Did you take a Hydrometer reading before you added your yeast?
The hydrometer is a winemakers best friend. This measures the level of sugar in the must. Take a reading.
Yeast converts sugar to alcohol. If there is not enough sugar, there is nothing there for the yeast to feed on. You need to add sugar to get your specific gravity to the recommended starting level in your recipe. (usually 1.080 to 1.095)
You can go ahead and add more sugar (about 1-2 cups)…stir about 2 minutes. Take a hydrometer reading.
Just make a sugar mixture by dissolving as much sugar into 2 cups of warm water as possible. Let the sugar mixture cool off and add it to your must.
Give it about 24 hours and it should start to ferment, hopefully solving your stuck fermentation problem.
Click here to instructions on how to use a hydrometer.
#4 Cause and Solution
Did you use too much sugar?
Occasionally we feel a little more is worth it. Not so with wine. One yeast packet can feed on up to 5 gallons of wine easily with the appropriate amount of sugar that is called for in a recipe.
If you have too much sugar and the yeast stopped working too soon OR if it is sluggish, you will need to add a yeast energizer (sometimes referred to as “super ferment”) and champagne yeast.
Dissolve 1/2 tsp per gallon of yeast energizer and 1 package of champagne yeast to a cup of warm water to get started. Your “must” should start working in a couple of hours.
Don’t see a wine making tip relating to the problem you are having? Go ahead and ask your question. If we don’t have an answer, we will find it for you.