11/27/2022 | pH | 8 MINUTE READ

The Importance of pH in Wine Making

ph in wine

Making wine is a lengthy process that’s completed over several stages. Winemakers are tasked with making sure that the wine they produce meets their quality standards. The quality of wine can be detected with pH measurements, which is why many winemakers speak about pH when highlighting the character of a bottle of wine.

When you measure pH, you can obtain readings that extend from 0-14. Anything below 7.0 is considered acidic, while every reading above 7.0 is known as basic or alkaline. The acidity in wine will affect its freshness and microbial stability while also acting as a preserving agent.

There are two scales that can be used to measure how acidic wine is, which include pH and total acidity, the latter of which is measured in grams per liter. The pH measurement aims to identify the total concentration of hydrogen ions that are present in the solution.

Certain acids will be more potent than others, which means that a higher number of ions are released into the wine. The primary acids that are found in wine include malic, lactic, and tartaric acids. The strongest of the acids is tartaric, which means that wine with high concentrations of tartaric acid will have lower pH readings. Even if there’s more acid in one wine, it could have a lower pH than the other wine in the event that most of the acid consists of the malic and lactic varieties.

Keep in mind that more acidic wines will have pH readings that are lower on the scale, which means that high concentrations of hydrogen ions equals a more acidic wine with a lower pH. A beverage like lemon juice typically comes with a pH range of 2-3. In comparison, wine and orange juice have pH readings between 3-4 in most cases. Some wines can reach just below 3.0.

A single point lower in the pH scale is around 10 times more acidic, which means that there’s a sizable difference between a 3.0 reading and a 4.0 reading. This article offers a more comprehensive look at how pH is used in wine making and why precise readings are essential to the quality of a bottle of wine.


How Does pH Affect Wine?

Grapes that have yet to ripen will have higher acid levels. Once the fruit begins to ripen, the acid levels will start to drop, which will result in a higher pH. Grapes that are too ripe will hardly have any acidity.

Winemakers are tasked with deciding when they should harvest a grape during the harvest season. This action must take place when pH levels are perfect. On the other hand, the sugar, tannins, and titratable acidity of the grapes will also change while the grapes ripen, which must be taken into account.

A reputable winemaker will consider all of these factors before choosing the ideal time to harvest the grapes. Different pH ranges are recommended for different wine varietals. The preferred pH ranges are:

  • Dessert wines – Less than 3.6
  • Sweet wines – Less than 3.4
  • Red wines – Less than 3.4
  • White wines – Less than 3.3

White wines are considered to have a better taste when pH levels are lower and acidity is higher. In comparison, dessert wines usually have less acid because of when the fruit is harvested. The grapes for a dessert wine are harvested well after they’ve started to ripen.

Acidity substantially changes the profile and taste of a bottle of wine. When pH levels are higher, the resulting wine should be rounder and softer. Many winemakers choose to use the pH measurement over the TA alternative as a result of pH measurements being more helpful in evaluating issues like microbial stability.

The reason that pH readings are usually kept below 3.8 in wine is because a higher pH means that bacteria can more effectively grow in the solution. The acidity of wine can also be influenced by time. Over time, wines typically become less acidic.

does ph affect wine

How Does pH Affect My Wine?

This measurement affects nearly all aspects of wine. The pH can affect aroma, flavor, carbon dioxide absorption, tartrate precipitation, color, age-ability, fermentation rate, stability, and malolactic fermentation. It’s also able to affect numerous chemical reactions that will occur during the fermentation process.

By reaching the right acid levels for a specific wine, it’s possible to lock in a color, aroma, and various flavors. The fermentation process can also be completed without issue. If the acid levels are lower than they should be, the wine may not have the right body or mouthfeel. The taste could also be weaker than winemakers would like it to be. In some cases, the wine may take on a more brownish color.

The stability of pH levels is also highly important. The majority of bacteria and fungi are unable to grow and thrive at pH levels that range from 3.0-3.75. If pH levels remain stable throughout the wine-making process, the wine should be protected from microorganisms that cause spoilage.

However, there are instances when allowing the wine to be maintained at the ideal pH range can create problems. In the event that you want to perform malolactic fermentation for your wine, the malolactic bacteria might be unable to survive for long enough to complete the fermentation process if pH levels are around 3.0.

Adjusting Wine pH

Adjusting wine pH is possible before the fermentation process begins. The pH levels should be properly adjusted before releasing the yeast, which means that the sugar content, tannins, and titratable acidity should also be altered.

There are several methods that can be used to alter pH levels, the primary of which include:

  • Malolactic fermentation
  • Blending wines with varying acid levels
  • Using a chemical process

If you perform the malolactic fermentation process, the wine that’s produced will have less acidity. Blending wines that have differing acid levels may be used to increase or decrease pH levels. Even though chemically increasing pH levels is the least recommended option, it’s also the simplest method. All that’s required is for an acid blend of tartaric, citric, and malic acids to be placed in the solution.

Reducing the acidity of wine with a chemical solution can be accomplished with calcium carbonate. Make sure that this method is only done when small adjustments need to be made. The preferable option is to perform malolactic fermentation, which will precipitate the tartaric acid out of your wine. You should take pH measurements before and after you attempt to alter pH levels.

adjusting wine ph

The Effects of pH Levels on Wine Quality

The pH levels of wine dictate what traits are present in the wine. Once you take pH measurements, you can measure the strength of acids, the quantity of acids, and the effects of the minerals in the wine. The pH of wine depends on the amount of acid, the amount of potassium, and the ratio of tartaric acid to malic acid.

When wine has very little acid and high amounts of potassium, pH readings should be high. Wines with more tartaric acid and lower amounts of potassium should have reduced pH values. Even though the pH values of wine can range from 2.9-3.8, most winemakers prefer a range of 3.0-3.5.

There are numerous advantages that come with maintaining a low pH value in wine. Low pH will stop bacteria from growing, allow sugar fermentation to have a more balanced progression, and improve control of the malolactic fermentation process. Low pH levels also directly influence how stable the wine is at hot temperatures.

When a bottle of wine is stored in a warmer area, any protein will precipitate out of it, which creates serious issues. The affected wines will then be treated with bentonite to get rid of excess proteins. More protein is able to be removed when pH readings are low. If pH levels increase, bentonite becomes less effective, which means that larger amounts of the substance would need to be added. Placing too much bentonite in wine can cause the unique flavors and aromas in the wine to dissipate.

A low pH will also lead to improved visuals for the wine. White and red wines alike have a better intensity of color. If wine has a high pH, bacterial fermentation becomes an issue. This problem causes chemical and biological instability as well as a poor color.


  • Low pH range (3.0-3.4) – Less
  • High pH range (3.6-4.0) – More

Amount of Color

  • Low pH range (3.0-3.4) – More
  • High pH range (3.6-4.0) – Less

Kind of Color

  • Low pH range (3.0-3.4) – Ruby red
  • High pH range (3.6-4.0) – Brown hues

Yeast Fermentation

  • Low pH range (3.0-3.4) – Not affected
  • High pH range (3.6-4.0) – Not affected

Protein Stability

  • Low pH range (3.0-3.4) – More stable
  • High pH range (3.6-4.0) – Less stable

Bacterial Growth

  • Low pH range (3.0-3.4) – Less
  • High pH range (3.6-4.0) – More

Bacterial Fermentation

  • Low pH range (3.0-3.4) – Less
  • High pH range (3.6-4.0) – More

What these factors indicate is that pH measurement is essential to the wine-making process. Before taking readings of a wine’s pH levels, make sure that you have a pH sensor that’s able to provide you with precise readings.

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Posted by Dominic O'Donnell on November 27, 2022

Sensorex is a global leader in the design and manufacture of quality sensors for water quality and process applications. The company offers more than 2000 sensor packages for pH, ORP, conductivity, dissolved oxygen, free chlorine, chlorine dioxide, UV transmittance and other specialty measurements, as well as a full line of sensor accessories and transmitters. Its expert technical support engineers solve analytical sensor challenges with custom designs and off the shelf products.

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