Can I Add Sugar During Fermentation?

Man Adding Sugar During FermentationWhen making wine should I add all the sugar all at once or can I add sugar to the wine during the fermentation?

Name: Mark
State: Ohio
Hello Mark,

In general, you do not want to add sugar during fermentation. You will want to add all the sugar to the wine before the fermentation – all at once, upfront. There is no real advantage to spreading the sugar throughout the primary fermentation, just as long as you are shooting for a reasonable level of alcohol (10% to 14%). Any wine yeast you choose to use will be able to readily ferment to this level of alcohol, even when all the sugar is added to the wine must before the fermentation.

The biggest reason you’ll want to add all the table sugar all at once, besides the fact it’s less work, is that it makes it easier to calculate your wine’s finished alcohol.

Sugar is what turns into alcohol during the fermentation. This is fermentation 101. To know how much alcohol the fermentation is making, you have to know how much sugar has been fermented. This requires you to know how much sugar the fermentation started with and how much sugar the fermentation ended with. The difference is what was fermented into alcohol. Both of these things can be easily determined with a hydrometer by taking a reading before and after the fermentation and comparing the two.

Shop HydrometersIf you add sugar to the wine during the fermentation, additional hydrometer readings will need to be logged to eventually know how much alcohol is in the wine. These additional calculations can be annoying and even hard to remember to do. It requires you to pull out the hydrometer each time you want to add more sugar and take a specific gravity reading both before and after the addition of the additional sugar.

The only possible time you would want to add sugar fermentation is if you intend to make a high-alcohol wine. In this case you would want to start out the fermentation with enough sugar to reach 13% or 14% alcohol. Then as the fermentation runs out of sugar – which is determined with hydrometer readings – you will want to start feeding sugar to the fermentation in intervals.

The goal is to end up with a wine that is high in alcohol but not too sweet to drink. The fermentation will come to a point where the wine yeast can do no more. Exactly when that will be is not a certainty. It varies from one fermentation to the next, depending on a number of variables. When this happens you want little to no remaining sugar in the wine. This is the reason why you would feed the sugar to the fermentation as it progresses beyond 14%.

Shop Wine Making KitsSo in the end I guess the answer to the question: “can I add sugar during fermentation?”, is yes you can. With the only side note being “but it only makes sense if you are making a high alcohol wine”. For any normal wine making situation, it is only creating more work to do so.

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.

19 thoughts on “Can I Add Sugar During Fermentation?

    • Paul, without knowing anything specific about the wine kit that you are making, I will say that we do not see any reason why you cannot add sugar 2 days after starting the fermentation.

  1. Raleigh, absolutely you can add sugar to a wine right before bottling. It’s a matter of personal taste. Remember though, it is important to added potassium sorbate at the same time, otherwise your bottles my start fermenting the newly added sugar. Here’s more info on this:

    Making Sweet Wines

  2. What is the highest ABV wine you have come across? I know Baul is 22 percent desert wine,but I haven’t heard of any higher.

  3. When I’m making my concord grape concentrate base with honey, I always put 3 quarts of the concentrate into 4. 5 gallons water, then add a half gallon honey, allow to ferment until it just starts to slow down and then add the other half gallon honey. Let it finish with its ferment and makes an unbelievable wonderful pyment. I use a 6 gallon fermentor and yes, it is pretty full.
    I will use 2 packets of Danstar D47 for this and it works perfectly!
    Making me thirsty for some…..To the cellar I am off………..

  4. I added 2 cups of sugar to my peach/apple wine that was fermenting for at least a day. It was fermenting fine. After I added the sugar it (trying to increase alcohol content ) decreased significantly almost totally. I am afraid i raised the temperature and killed the yeast. If that is the case should i add potassium sorbate?

    • Marty, adding potassium sorbate will not prevent fermentation activity in a wine that did not complete fermentation. You need to get the fermentation to complete. If you think that high temperatures damaged the yeast, you need to get the temperature down between 70-75 degrees and add a new packet of yeast. I would also recommend monitoring the fermentation progress with a hydrometer. Since you can not always tell by looking, a hydrometer is really the only way to track the fermentation progress.

  5. INCORRECT! It’s terrible to add all the sugar before fermentation because then you can actually turn the sugar into a preservative instead of a fermentation tool. Better to add it through the process to achieve control to the alcohol level and mind the process. If you’re making Franzia type wine, then dump it in the beginning and go on vacation.

  6. so in other word i could ad sugar during fermentation? right?? thank you soooo much. I’m actually doing a tomato wine as a school project and i want it to be the best. 😀

  7. I started a wine kit and only put 2 cups in instead of 2 lbs. it’s been going on the first stage for 2 weeks. Could I add more sugar without ruining anything or should I just keep going with the process and chalk it up as a mistake.

  8. Hi. Thanks for a great blog that I follow from my home in Denmark. And pardon my poor English!
    I have a problem I hope you can help with:
    During the first fermentation of apple cider I’ve experienced that the yeast have ‘eaten’ all the sugar in my apple must and the Oechsle now is 1000 (it started out with 1060!) And it has only been a week since I added the yeast.
    Can I add additional sugar – and if yes how much) when I rack the cider in to the carbons?

    • Rikke, it just sounds like your fermentation completed quickly. The only reason you would add more sugar is if you want more alcohol. If more alcohol is your goal, one pound of sugar in a 5-gallon batch will raise the potential alcohol by about one percent.

  9. Ok so I have 6 gallons (actually 36) of Catawba going the original gravity from winery was 16.75 Brix / 1.068. Let it ferment down to -1.3brix/ .996 after second rack then added sugar and brought the Brix back to 17/1.070. What is the equation to figure abv when this finishes?

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