Calculating the energy value of wine

After December 8, 2023, all wine which was not produced before that date must include disclosure of ingredients, allergen, energy, and nutrition information, according to Regulation (EU) 2021/2117.

Noncompliant wines, must be removed from the market and may have penalties applied as well, according to the law. See Regulation (EU) 1306/2013 Chapter IV, Article 89.

So, what is energy and how is it calculated

The definition of energy in wine:

Energy value of wine is usually expressed in terms of a term known as calorific value. The calorific value is defined as the quantity of heat liberated in calories by the complete combustion of a unit mass of wine in excess air or oxygen under specified standard conditions. The calorific value depends on the nature of the wine and relative proportion of alcohol, organic acids, carbohydrates and polyols present in that wine (fat and protein will be negligible or nil in wine). It is usually expressed in kilo calories and the standard mass taken is 100 ml.

The unit of energy

The energy value of wine can be expressed in terms of kilo calories (KCal) or Kilojoules (KJ).

Kilo Calorie

One kilo calorie is the quantity of heat required to raise the temperature of 1 kg of water through 10C. It is one thousand times the small calorie used in physics measurements. 

Kilo Joule

One kilo calorie equals 4.186 kilo joules. Hence thousand kilo calorie equals 4.186 × 103 kilo joules or 4.186 mega joules.

What parameters should be considered to accurately calculate the energy value of a wine

To be precise and create an accurate energy calculator one needs to look at the main wine component releasing energy during the digestion.

Ethanol

‍It is by far the main factor in the calculation of wine energy. Typically, wines average between 12% and 13.5% alcohol/vol bringing between 87.5cal/100ml to 94.5 Kcal/100ml.

Carbohydrates

‍To keep it simple carbohydrates in wine are all the sugars left after the alcoholic fermentation.

Typical dry wines will have between 1 and 5g/l of residual sugar. In term of calories /100 ml that is equivalent 0.04 Kcal /ml to 0.2 Kcal/100ml. Whereas a sweeter wines with 130 g/l of residual sugar will contribute 5 kcal/100ml.

Organic Acids

‍The predominant fixed acids found in wines are tartaric, malic, citric, and succinic.  Their respective levels found in wine can vary greatly but in general one would expect to see 1,000 to 4,000 mg/L tartaric acid, 0 to 8,000 mg/L malic acid, 0 to 500 mg/L citric acid, and 500 to 2,000 mg/L succinic acid.  All of these acids originate in grapes with the exception of succinic acid, which is produced by yeast during the fermentation process. Some wines go through malo lactic fermentation (bacterial fermentation), the Malic acid will then be transformed into lactic acid. Grapes also contain ascorbic acid (Vitamin C), but this is lost during fermentation.

Even if these acids are very important for the taste and balance of the wine they play a small part in the energy calculation. A typical wine with a TA of 7 will bring 0.3Kcal/100ml.

Polyols

‍They are a specific group of sugar alcohols. In wine, Polyols come from the yeast during the alcoholic fermentation. The main Polyol in wine is glycerol and when it’s production stops, D-arabitol, D-sorbitol and D-mannitol are produced.

Depending on the fermentation conditions the Polyols can go from 4g/l up to over 20g/l when grapes are affected by Botritys.

An average value of 7 g/l is an accepted value for a standard wine. Polyols have a low influence on the overall calories in wine. Even with 20g/l it only brings 0.48 Kcal/ 100ml.

What about fat, protein, and salt?

As it stands it is a requirement to display the amount of fat, protein and salt to follow the new EU wine label requirements. The reality is those value will be NIL for 99% of all wine, however we still must display these nil or low amounts.

Protein

Protein is reacting with tannin in red wines and therefore not present. in white wines, winemakers fine the wine to eliminate excess protein to avoid undesirable haze in the bottle.

Fat

There is no fat in wine as it is made of grapes containing no fat.

Salt

There is usually very small amount of salt (NaCL) in wine and most wines will have between 5 and 30mg/l of NaCl. There is some exception for wine made from grapes grown close to the sea where amount of salt can be 50-60mg/l, or in some vineyards where the irrigation water has high level of NaCl. For example, in Australia some wines have concentration of around 1000mg/l of Salt. 

To put thing in perspective, the agreed daily salt needed by a human is around 2300mg/ day.

In conclusion

When calculating the energy value of a wine the most important factor is the alcohol content of the wine. Even if Sugar, acids, and Polyols all play a part in the calculation they play a relatively minor role in the overall energy value of the wine, however they should be part of your calculation for the sake of accuracy.

Hopefully Europe will come to reason and remove the need for producers to display the fat and protein content of wines. Salt could also be reviewed for the majority of wine too, considering the minimum amount found in normal wine.

How does PinotQR handle energy calculations?

Our e-labelling solution comes with an easy and automatic calculator so you only have to enter your alcohol, residual sugar and organic acid (TA) for each wine and we'll do the rest.

We do let you override the other six values, though, just in case your wine is a bit unique! Either way our service offers a quick and painless process to handle your e-labels.

If you have any further questions regarding calculating energy values in wine please don't hesitate to send us a message.