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How to Chaptalize Must / Wine

What is Chaptalization?

Ask any experienced winemaker about factors that can come into play to make each year's harvest unique, and there's a good chance mention will be made to the local growing conditions or climate. Some years, the fruit will be fully ripe and bursting with flavor - while in other years (especially during poor growing conditions), the fruit seems like it takes forever to ripen and the harvestable quantity is diminished.

Wine made from diverse growing seasons requires different must adjustments in order to make good wine year in and year out. If you've ever made blackberry wine according to your grandfather's old recipe and wondered why one year's wine is great but the next one isn't, one possible explanation is that the sugar content of the blackberry must varied widely from one year to the next.

To get consistent results, vintners test the raw fruit juice to determine the must's quality - and based on the results of these tests, make the necessary chemical adjustments to ensure a well-balanced wine.

This winemaking article will focus on one aspect of creating a well-balanced wine - controlling the alcoholic content of your wine. The amount of alcohol in your finished wine is directly proportional to the amount of sugar found in the raw fruit juice, or must. This makes sense, since we know that wine yeast converts the sugar to alcohol and carbon dioxide. The more sugar you have, the more alcohol you'll get. This article does not go into any great detail to discuss other methods of adjusting your must, such as adjusting your acidity and pH.

This article is intended for home winemakers who make their own wine from scratch (from fresh grapes or fruit). If you make wines from kits, you will certainly benefit from this knowledge, but you won't have to worry about chaptalization since modern wine kits are already chemically balanced for consistency.

What is chaptalization?

Chaptalization (also known as "sugaring") is the procedure of adding sugar to grape juice or must prior to or during fermentation. As you have already surmised, winemakers chaptalize must to compensate for poor growing seasons, or if they're located in areas of the world that experience cooler climates.

By boosting the sugar content to appropriate levels, you can help ensure your wine is well-balanced... but be careful - adding too much sugar is just as bad as not having enough!

Why is it important to chaptalize?

The main reason it is desirable to chaptalize your wine is that your wine will have the proper alcoholic content to help ensure a well-balanced wine.

There are three aspects of must you should measure and adjust (if necessary) prior to pitching the yeast. They are acidity, pH, and the amount of sugar. These three aspects of wine work together to create the taste of the wine. If only one of these readings is out of whack, the wine that is made from that particular batch of must is said to be "out of balance" and the overall taste of the wine will suffer. If the wine is too acidic, it will taste like battery acid; if it doesn't contain enough alcohol, the wine will taste thin. Properly balanced wines have the right amount of pH, acids, and alcohol and taste great. As previously noted, we will concern ourselves solely with the adjustment of sugar in this article.

Here are some other benefits of chaptalization:

How to chaptalize wine

  1. Create the must by getting the juice from your grapes or other fruit
  2. Take a hydrometer reading
  3. Compare the hydrometer reading to your desired specific gravity
  4. Make appropriate sugar additions to must
  5. Pitch yeast to start fermentation

The first thing to do is to generate the must. Mostly, this involves squeezing the fruit to get the juice flowing! Once your must is in the fermentation vessel (for most home winemakers making small batches, the fermentation vessel at this point is a food-grade plastic bucket), take a specific gravity reading with your hydrometer.

Take the specific gravity reading and see where it falls in the chart below.

Sugar in One
Gallon of Must
 Brix  Potential
Alcohol (%)
1.040 0 lb.14 oz. 10.0 5.1
1.045 1 lb. 0 oz. 11.5 5.8
1.050 1 lb. 2 oz. 12.5 6.5
1.055 1 lb. 3 oz. 14.0 7.2
1.060 1 lb. 5 oz. 15.0 7.8
1.065 1 lb. 7 oz. 16.5 8.6
1.070 1 lb. 8 oz. 17.5 9.2
1.075 1 lb. 10 oz. 18.5 9.9
1.080 1 lb. 11 oz. 20.0 10.6
1.085 1 lb. 14 oz. 21.0 11.4
1.090 2 lb. 0 oz. 22.0 12.2
1.095 2 lb. 1 oz. 23.0 12.7
1.100 2 lb. 3 oz. 24.0 13.4
1.105 2 lb. 5 oz. 25.0 14.1

For white wines, your target specific gravity should probably be in the 1.085 to 1.090 range. If allowed to ferment to dryness, this would equate to a wine that contains about 11.5% to 12% alcohol. For red wines, your desired starting specific gravity would be around 1.090 or 1.095.


For the sake of illustration, let's say you've prepared 6 US gallons of must and took a hydrometer reading. After making corrections to the reading based on the temperature of the must (most hydrometers are calibrated at 60 degrees Fahrenheit), you discover that your red wine's starting specific gravity is 1.070. Since we're making a red wine, our desired starting specific gravity is 1.090.

So how much sugar should we add? Not only that, but what kind of sugar should be used?

White granulated sugar - the kind you buy in the grocery store - is the sugar of choice. It doesn't matter if it came from sugar beets, sugar cane, or whatever. Just don't use brown sugar, since it contains molasses and will really throw off your taste.

We can tell from the chart that must with an SG (specific gravity) reading of 1.070 contains one pound and a half of sugar per gallon. To discover how much sugar is present in the raw must, then, we would simply multiply one and a half pounds by 6. We do this since (at least in this example) we're dealing with 6 gallons of must:

1.5 lbs. per gallon  X  6 gallons = 9 lbs of sugar

Our desired starting SG is 1.090, which is equivalent to 2 pounds of sugar per US gallon:

2.0 lbs per gallon  X  6 gallons = 12 lbs. of sugar

The difference between the two, then, is the amount of sugar to add to bring our must to the desired starting SG:

12 lbs. - 9 lbs. = 3 lbs. of sugar

Our math tells us we need to add 3 pounds of sugar to bring the must up to standard. This is a good original estimate to start with, but I would suggest you err on the side of caution, and add a bit less than this - at least initially until you get some verification from your follow-up hydrometer readings. Why? Well, you can always add more sugar if you need to, but you cannot take it out once it's been put in!

As my personal rule of thumb, I only add 85% of the calculated sugar to my must the first time around. I figure I can always add sugar more later, if my subsequent hydrometer reading tells me so.

Most hydrometers, besides telling you the specific gravity of your must, will also offer a scale which tells you how many ounces of sugar (per US gallon) are contained in your sample. You could alternatively calculate the amount of sugar to add using this scale and applying some simple math.

Using a similar starting SG of 1.070, my own trusty hydrometer tells me that I would need to add about 7 ounces of sugar per gallon to get to my desired SG of 1.090 for my six gallon batch. When I do the math, 6 times 7 oz. equals 42 ounces of sugar to add. This is 6 ounces less than the amount of sugar I determined from the first calculation. After doing the calculation this way, it's easy to see why I always err on the side of caution, and add 15% less sugar than is initially called for by the chart shown, until I am sure what the resulting SG will be.

Adding the sugar

All right, now it's time to add the sugar to your must. DO NOT simply dump the sugar in your must; my experience is that sugar does not always fully dissolve as fast as you want it to, especially if the liquid you're mixing it with is only at room temperature. If you're impatient and try to chaptalize too quickly, you will accidentally add too much sugar since some of it won't dissolve into solution until after you've gone away.

The sugar itself needs to be sanitized. I recommend removing a bit of strained must (no solids) and warming it slightly in a sanitized saucepan on the stovetop. Do not allow the mixture to smoke or boil. Add sugar slowly, and stir with a sanitized spoon until it is completely dissolved. Once the slurry is cooled, you can reintroduce the sugared must to the rest of the batch. Then vigorously stir to ensure proper mixing - this also oxygenates the must (which is good).

Finally, treat your must for other issues (pH, acidity), add some food for your yeast, then rehydrate and pitch your yeast to kick off fermentation.

Other factors to consider during chaptalization
Besides simply adjusting the amount of sugar in your must, there are other things you should consider. Among them:

If you're making a wine from scratch, checking the must's specific gravity - which provides an indication of sugar content - before you pitch the yeast is one of the best first steps to ensure a well-balanced wine. If your must doesn't contain the requisite amount of sugars from the start, the alcoholic content of your wine will be lower than you expected - and the wine may taste "off".

Should your hydrometer readings indicate that the starting specific gravity isn't high enough to produce a balanced wine, you should add sugar (chaptalize) to the must and build up the sugar content according to the methods described in this article.


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