Everything you need to know about lactic acid (E270)

dans le vin

Find out more about lactic acid (E270), its role in winemaking, its effects on wine balance and its many uses in the food industry.

Lactic acid, also known as E270 in the food industry, is a naturally-occurring organic compound. Present in various fermented products such as yoghurt, it also plays a key role in oenology. Produced during malolactic fermentation, it softens and balances wines by transforming the sharper acidity of malic acid into a softer and, for some wines, more pleasant acidity.

What is lactic acid?

Lactic acid is an organic molecule produced naturally during the fermentation of certain foods and beverages. It is formed mainly by the action of lactic acid bacteria on substrates such as lactose or glucose. It is found in common fermented foods such as yoghurt, cheese and sourdough bread.

In oenology, lactic acid is produced naturally in wine during malolactic fermentation. This natural process occurs after alcoholic fermentation, when lactic acid bacteria transform the malic acid present in the grapes into lactic acid.

Lactic acid is one of the different types of acid that can be found in wine, along with citric acid, malic acid and tartaric acid.

What role does lactic acid play in wine?

Lactic acid plays a role in the balance and flavour profile of wines by regulating acidity. When produced during malolactic fermentation, it softens the flavours of the wine by replacing the sharp, incisive acidity of malic acid with a rounder, creamier acidity. This process is particularly sought-after in red wines and certain white wines, where it contributes to buttery aromas and a smoother texture.

What is the effect of lactic acid during vinification?

Lactic acid has a major impact on winemaking, particularly through its role in malolactic fermentation. This process changes the perceived acidity of the wine by reducing the amount of malic acid – sometimes considered too sharp – and increasing the proportion of lactic acid. This transformation brings a number of benefits:

Increased sweetness: The wines are rounder, with sweeter, more balanced flavours.
Improved texture: The aromas become creamier, often described as buttery or milky.
Greater stability: The wine becomes more microbiologically stable, because the active lactic acid bacteria neutralise certain undesirable agents.

Lactic acid is particularly popular in winegrowing regions with cool climates, where grapes naturally contain more malic acid. Where this is the case, malolactic fermentation is essential for adjusting acidity and ensuring a balanced taste profile.

When is this pH regulator added to a wine?

In most cases, lactic acid forms naturally in wine during malolactic fermentation. However, it can also be added by winemakers in a controlled way to adjust the acidity of a wine.

It can be added at various stages in the winemaking process:

In the must: Before alcoholic fermentation, when the winemaker wants to intensify the initial acidity of the grape juice to obtain the desired wine profile.
After alcoholic fermentation: To complement malolactic fermentation or to further refine acidity.

The direct use of lactic acid in oenology is strictly regulated, with precise thresholds set to protect the integrity of the wine.

Is lactic acid also used in food?

Lactic acid is a common ingredient not only in wine, but in the food industry. Valued for its acidifying and stabilising properties, it is used in a wide variety of products:

Dairy products: Yoghurts, cheeses and fermented creams.
Beverages: Fruit juices and craft beers.
Bakery products: Sourdough bread and other fermented products.
Jams and jellies: Lactic acid balances their flavours and extends their shelf life.

Its slightly acidic taste and ability to lower pH make it a key ingredient for improving the texture, flavour and stability of food products.

Lactic acid, a discreet but essential friend of the winemaker, enhances the taste of wines and food products without disturbing their natural balance.