How Sweet It Is: Chaptalization

Some time ago, I had the pleasure of receiving four sommeliers into my home winery to sample my Cabernet Franc. Three of the four gentlemen were from France, one of them from the Loire Valley, home of the best Cab Franc (in my opinion) this planet produces.

After a minute or two of sniffing and slurping and — finally — swallowing, they rendered a succinct opinion: “It could use more body.” The appraisal didn’t really come as a surprise to me. I had suspected there was something missing in the mouth, but couldn’t quite put my finger on it. Body. Yes. That was it. My next question, of course, was, “Why?” And the answer they all gave me was this: low alcohol.

This was a surprise, because vintage the wine was produced from was an above-average year for the grape-growing region of Niagara, Ontario. I’d been pretty proud of the fruit I’d picked up — 530 lbs. (240 kg) of fresh grapes with a pH level of 3.2, moderate acid and a sugar level of 20.8° Brix. I’d babied this batch through fermentation, malolactic and aging in French oak. Even so, my next question was, “If you ordered this wine at a restaurant, would you send it back?”

“Good heavens, no,” one of them replied in his cool Parisian accent. “It is a nice light plonk (slang for table wine). But I would definitely note that it was low on alcohol.”

“Hmmm,” I said, realizing I had another 300 bottles of this stuff. “What advice would you give me, to make my wine better for the next time?” The answer: “Add sugar before fermentation.” They must have seen the horrified look on my face. As far as I was concerned, adding sugar to must before fermentation was…well…cheating. No?

“Not so,” said one of them. “Where I come from in the Loire, adding sugar, or chaptalization, is practiced when necessary, and is quite acceptable. Burgundy also.”

This surprised me. Loire Valley was the center of the Cabernet Franc universe, as far as I was concerned. I’d fantasized about making wine as fine as that, and suddenly wondered how many bottles of chaptalized wine I’d enjoyed. I knew that some wine-producing regions forbid the practice — like Bordeaux. But further research indicated that Germany, several other European countries, Canada and the United States permit chaptalization when necessary. In the United States, for example, federal law permits chaptalization under the Code of Federal Regulations (Title 27, Part 24.2), allowing commercial wineries in cooler states, like Oregon, to chaptalize when necessary.

Chaptalization. Though I’d heard and read of it often, until that very day, I had shied away from the practice, sincerely believing that it was a sacrilege to add sugar to your must. A vintage is a vintage, I said. Good or bad. And what you get is what you get. But that was then. Today, I am an enlightened man.

Why, oh why, should I chaptalize?

If you happen to be an avid winemaker, then I don’t need to tell you that the level of alcohol in your finished wine is directly related to the level of sugar in the must before fermentation starts. Alcohol is a by-product of yeast after it eats sugar. The more sugar it eats, the more alcohol it produces. It’s that simple.

If you are strictly a kit winemaker, sugar is not something you have to worry about. Those adjustments have already been made for you. But if you make wine from fresh juice or crushed grapes, you’ll want to pay close attention.

There are three specific factors that determine the exact moment to harvest grapes and the ultimate quality of your wine: acid, pH and sugar. Unripe grapes are high in acid, low in sugar. As your grapes ripen, they will progressively increase in sugar and drop in acid. You’ll be looking for the right amount of acid (from 0.6 to 0.8 percent for reds and from 0.65 to 0.85 percent in whites). Acid protects your wine from spoilage organisms and gives your wine its crisp, thirst-quenching characteristics. Too much acid tastes — well, like acid. Too little makes your wine flabby and pathetic. This is why you’ll also be concerned about your pH levels. Optimum pH in ripe grapes is 3.1 or 3.2 for whites and 3.4 for reds. If your pH is too high, your wine will be colorless, bodiless, and sickly. Like acid, your pH level will determine your finished wine’s ability to survive after it’s bottled. But for this article we’ll focus specifically on sugar — and alcohol.

So why is alcohol that important in the first place? So what if your plonk is light?

There’s definitely nothing wrong with a light wine. That particular Cabernet Franc ended up with an alcohol level of about 11.5% — and though 11.5% isn’t bad, my sommelier friends picked it up. Alcohol in wine, like acid, inhibits the growth of spoilage organisms. Low-alcohol wines, therefore, have a poor immune system against microscopic disorders that can turn your hooch into salad dressing. Your wine, though soft, will be flabby and short-lived.

As a guide, the level of alcohol you might want to strive for in a dry red wine is 12 to 12.5%. The average bottle you pick up at your local wine store hovers in this range. The alcohol level of a dry white averages about 11 to 11.5%. But for the sake of simplicity, let’s focus our demonstration on a dry red of about 12% alcohol, and conclude that the level of sugar you want to find in your must to get that should be about 22° Brix.

How to Measure Sugar in Must

What does 22° Brix actually tell you? The degrees Brix is the approximate percentage of sugar that exists in your must. Quite simply, every degree of Brix that your must registers is the same as saying that for every 100 grams of grape juice, about 1 gram of it is sugar; or, 1% sugar. So, if your grape must is 22° Brix, approximately 22% of your must is sugar. Once the yeast start eating it, they will convert some of it to carbon dioxide, and approximately 55% of it to ethyl alcohol. So, once you know the percentage of sugar in your must, you can estimate the potential alcohol it will produce. Simply multiply your Brix reading by 0.55. Now, because yeasts differ and their living conditions vary, the exact amount of alcohol produced will waver, more or less. But this is the general picture: Brix X 0.55 = % alcohol.

If you grow your own grapes, an excellent field tool for measuring Brix is the hand refractometer, a small device about 4 inches (10 cm) long that measures sugar by the way it refracts light. By putting the grape juice from a crushed berry onto the glass prism at one end and reading the scale through the lens at the opposite end, you can instantly know the degrees Brix of your grapes.

But if you buy your grapes from the local vineyard, and the vineyard owner doesn’t give you the sugar level of the grapes, the tool you would be using to measure this yourself is a hydrometer. The hydrometer is a sealed glass tube containing a scale used to measure the specific gravity of a fluid. It looks and floats upright like a thermometer. In water the specific gravity scale would read 1.000. The thicker the fluid, the higher the tube floats, and the higher the reading. The amount of dissolved sugar in your grape juice will determine its thickness. More sugar, more thickness. Once you know the specific gravity of your unfermented juice, you will know the sugar level — and can calculate if more is needed.

The best hydrometer to use is the 3-scale, where the paper scale sealed in the glass tube measures three things: specific gravity, Brix and potential alcohol. Even better is a 4-scale hydrometer with your sugar reading already calculated for you.

  1. After sanitizing your hydrometer and test cylinder, place the cylinder on a level surface and add (using a sanitized wine thief) a sample of grape must that’s free of visible solids. Leave enough room in the cylinder for fluid displacement when you insert the hydrometer. Give the hydrometer a spin, to free it of clinging bubbles that can make it float higher and influence your reading. Record the specific gravity reading on the scale. You will notice that fluid tension creates a curved surface where it meets the hydrometer stem. This is called the meniscus. The true reading is at the lower part of the meniscus. In the example shown, the specific gravity reading is 1.060.
  2. Remove the hydrometer, pour your test sample away, and clean the apparatus. Now that you have the specific gravity reading of your must, you can calculate the level of sugar in it, and figure out how much — if any —needs to be added. For the sake of demonstration, I’m using a very low reading of 1.060. Using your 3-scale hydrometer, a specific gravity reading of 1.060 contains approximately 15 °Brix, with a potential alcohol of about 8% in your finished wine. Our goal of 12% alcohol for a dry red wine would require a specific gravity of about 1.090 and a Brix of 22°. If you were shooting for a dry white wine, you would look for a Brix level from 20.5 to 22 °Brix. Either way, clearly, we need to add sugar.

How Much Sugar to Add

To the inexperienced winemaker, the first impression may be that adding sugar to unfermented juice will produce a sweet wine. Not so.

Remember, the yeast you add to your must, will eat the sugar — all of it — to produce alcohol. With all the sugar gone, there is no residual sweetness. Your wine will be dry, unless you put in too much sugar. This might, among other things, raise your alcohol above 15% — the point at which some yeast strains become inoperable, resulting in a stuck fermentation. So calculating the right amount of sugar is paramount. Armed with our specific gravity of 1.060 and a Brix of 15 °, we can figure out how much sugar to add.

For the sake of a benchmark: Grape must with a specific gravity of 1.090 and a Brix of 22  ° has a potential alcohol of about 12.2% and is generally what every winemaker shoots for in a dry red table wine (1.082 to 1.090 for whites). The objective, then, is to calculate the amount of sugar needed to bring a must of 1.060 (15 °Brix) up to 1.090 (22 °Brix). How do we do that? Well, if your Brix is 22 °, then 22% of your grape juice is sugar; 22% of 1 litre is 220 grams, and 22% of a gallon of must weighing a standard 8.33 pounds, is 1 pound 13 ounces. You can make your own calculations and use simple subtraction, as follows:

A specific gravity as low as 15 °Brix means your must only contains about 15% natural sugar. Once the yeast eats all that sugar, the byproduct they’ll have left behind will only be 8% alcohol — not enough to keep the microorganism meanies at bay. So, you’ve got to give the yeast more sugar to eat so they can produce more alcohol. How much more? If the required sugar for 22 °Brix is 220 grams per litre, then the difference is 220 grams minus 150 grams, which leaves you with 70 grams. Therefore, you need to add another 70 grams per litre of sugar, or 9 ounces of sugar per US gallon. So, if your primary fermentation pail is 5 US gallons, you’ll be adding 9 ounces of sugar, times 5 gallons, which is 45 ounces, or 2 pounds, 13 ounces. Now, your yeast will have enough sugar to produce 12% alcohol.

A minor point: You may notice slight variations in different hydrometer scales. Not to worry. While researching this article I discovered, in more than seven publications and my own 3-scale hydrometer, that no two scales were identical, each varying a few points depending on whether readings were taken from real grape must or a sugar-water solution, or under other varying laboratory conditions. For your home winemaking needs, the differences are insignificant and all the scales work.

How To Add Sugar

Now that you know how much sugar to add, it might be tempting to just measure it out and dump it into your must. Don’t. Your poor must won’t know what hit it. With all this undissolved powdery stuff crystallizing on the bottom, the yeast will go into shock and have a nervous breakdown, and the party will be over. For yeast to consume sugar, it has to be thoroughly dissolved. You’ll want to sanitize a separate container, pour some must into it (with solids strained out) and warm it slightly. Add sugar a bit at a time, stirring with a sanitized spoon, until it is completely dissolved. After it cools, stir the mixture into the original batch.

Note: If you’re tempted to push your alcohol beyond 14%, it may be done by gently feeding more sugar into the already fermenting must. Take hydrometer readings as you go.

A Word on Temperature

Most hydrometers are calibrated at a temperature of 59 °F (15 °C). (Some are calibrated to other temperatures; check the instructions that came with yours.) Since the density of fluids will read slightly different when the temperature changes, it might be good to make a correction. It’s not likely you will be measuring the specific gravity of your grape must at 59° F. Most likely it will be in the high 60’s or low 70’s (high teens to low 20’s C). Keep this rule in mind: For every 9 °F (5 °C) the temperature rises above 59 °F (15  °C), add 0.001 to your gravity reading, and add 0.25° to your Brix. For every 9 °F (5 °C) under 59 °F (15 °C) subtract 0.001 off the SG and 0.25 °Brix off the Brix. Corrections can be even more precise if you want to get into the scientific nitty-gritty, but if you don’t make the correction at all, it won’t be a disaster.

What Kind of Sugar

Pure white table sugar is very effective. This may be beet, cane or corn sugar. Wine yeasts consume these easily, leaving no residual flavors. Many winemaking retailers offer pure white corn sugar for winemaking. Avoid castor and brown sugar, or anything that contains molasses. This will give your wine an undesirable taste. There are fancier fermentable sugars if you want to be particular, but for today we’ll keep it simple.

Having read all this, you still might prefer to ferment your wine on its own natural sugars at crush, regardless of potential alcohol. That’s a matter of preference and there’s nothing wrong with it. But now you can be confident that chaptalization is a legitimate option, offering yet another way to grow and improve your skills as a home winemaker.