How To Fix A Stuck Fermentation

A Fixed Stuck FermentationDo you have any information on how to fix a stuck fermentation or should I dump this batch of wine out?

Name: A. J.
State: WI
Hello A J,

Having a stalled or stuck fermentation is a problem that can happen from time to time, particularly when making wine from fresh fruits. But having a stuck fermentation does not mean that the wine is ruined or has gone bad. It just means that the environment in which the wine yeast currently is in is not suitable for a continued fermentation.

If you have a fermentation that has stalled, the first thing you need to do is take a hydrometer reading to confirm that the fermentation is, in fact, stuck and not simply done already. While the typical fermentation will carry on for one, sometimes two, weeks, we have seen fermentations finish as quickly as 3 days. By taking a hydrometer reading you can confirm whether or not there are still sugars in the wine that need to be fermented.

If the hydrometer indicates that all the sugars are gone, then the fermentation is done, regardless of how many days it has been fermenting. You do not have a stuck fermentation. There is no reason to add more sugar or more wine yeast. This solution to the problem is to simply move on to the next step of the wine making process as listed in any wine recipe you are following.Shop Hydrometers

If you do find that you have a stuck fermentation, your job as a winemaker is to figure out why – to figure out what caused the stuck fermentation. There are many reasons why this problem can occur: the wine must’s temperature is too cool, or there’s too much alcohol already in the wine for the yeast to continue, etc.

Because there are several potential reasons for a fermentation to become stuck, we have put together The Top 10 Reasons For A Fermentation Failure. It goes over the 10 most common reasons for having a stuck fermentation – from the most likely to the least likely. There are other reasons besides these 10, but in our experience, these 10 causes cover well over 95% of the stuck or non-start fermentations we run across.

Once you know the cause of a stuck fermentation then you will know how to fix the stuck fermentation. Most of the 10 reasons have very simple solutions that involve simple techniques to remedy. The trick is to determine what caused the problem before trying to fix it.Buy Yeast Energizer

As a final note, realize that a stuck fermentation is not the end of your wine. It is only a delay in the wine making process, a challenge to be overcome. Once the problem is fixed, the fermentation will start up again and your wine will turn out just as nothing ever happened.

Happy Winemaking,
Ed Kraus
Ed Kraus is a 3rd generation home brewer/winemaker and has been an owner of E. C. Kraus since 1999. He has been helping individuals make better wine and beer for over 25 years.

11 thoughts on “How To Fix A Stuck Fermentation

    • Jerry, actually storing yeast in the refrigerator will keep it fresh longer. If you store your yeast in the refrigerator, it will be fine for at least two years. It is important to note here though that you should never store your yeast in the freezer. Doing so damages the cell walls of the yeast with freezer-burn. The cell walls of the yeast actually become damaged from the effects of freezer-burn.

  1. My experience with a stuck fermentation was the result of having too much sugar. The level of alcohol in my wine killed the yeast. I siphoned out two gallons of wine from my six gallon fermenter and replaced the wine with water to lower the alcohol content. I added yeast nutrient, yeast starter, and yeast to the wine and the fermentation restarted.

  2. I was given five cases of condensed cranberry juice, add two cans of water per can, took 18 cans, but fermentation never started. How can I get it to start!

  3. I started my plum wine on 7/30 from fresh plumcots Initial gravity 1.090 Transferred to secondary on 8/10 sg 1.010. Tasted very alcoholic.
    Racked again on 9/4 sg 1.015 yes I double checked it.
    9/13 checked sg 1.010, suspected stuck fermentation added 5 tsp yeast nutrient.
    Checked it today and sg still1.010 tasted sweet. But not too sweet (actually tasted pretty good and it was very clear.
    Shouldn’t the sg have dropped by now and why does it taste sweet?
    Not sure how to proceed or should I just leave it alone?

    • D. Finley, If there has been no change in the specific gravity reading in several weeks, the fermentation is stuck. Before you bottle the wine you need to get the fermentation to complete or it could start up again in the bottles. I would recommend reading the article posted below on the most common causes of a stuck fermentation. Before you can restart the fermentation, you need to know what caused it to because stuck.

      Top Reasons For Fermentation Failure

    • He still has a little over 1% sugar in his wine if he had a 1.090 start sg. and a 1.010 finish. He’s only at 11% ABV so his ABV should not be to high unless he used a low% yeast? Like Bread yeast or something or it got to cold; if infect it is even stuck at all? I would give it another week or so to see if it finishes. I don’t think its stuck? Its just slowed down because the ABV is getting higher. This is why I stopped using an air lock!

  4. Can you have “stuck fermentation” in making beer?
    Your 10 reasons for Fermentation Failure only
    referenced wine. Thanks.

  5. When I have this problem I will hang a heating pad that I use for my back on the side of the carboy. Then I cover it with a large towel. Gently heating the carboy a few degrees is usually enough to get the fermentation going again.

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