Measuring Dissolved Oxygen In Wine

The most accurate way to measure dissolved oxygen in wine is using a dissolved oxygen meter. This device measures the amount of oxygen that is dissolved in the wine, which can indicate how much air has entered the bottle. The meter works by using a sensor that reacts with the oxygen in the wine, producing an electrical current that can be measured.

Wine is a complex and ever-changing liquid that requires careful monitoring throughout the winemaking process. One critical parameter that winemakers must keep a close eye on is the level of dissolved oxygen (DO) in their wine.

Dissolved oxygen can impact anything from the wine’s color and aroma to most importantly taste, making it essential to measure and control. With the right equipment and techniques, winemakers can accurately measure DO levels in their wine and make adjustments as needed.

In this article, we’ll explore the importance of measuring DO in wine, the different methods available, and how winemakers can use this information to create high-quality wines that will impress even the most discerning palates.

Dissolved Oxygen In Wine

Wine is a delicate balance of different chemical compounds, and oxygen plays a critical role in how it tastes and ages. Oxygen can enter wine at any stage of the bottling process. Oxygen can help soften harsh tannins, improve the wine’s aroma, and give it a smoother mouthfeel.

However, too much oxygen can be detrimental to the wine’s quality, causing it to age prematurely or develop off-flavors. Therefore, winemakers must carefully control the amount of DO in their wines.

It is recommended that bottled red wines have a DO level below 1.25 mg/L, and for white/blush/rose wines, below 0.6 mg/L of dissolved oxygen.

How Does Oxygen Enter Wine?

Oxygen is unavoidable as it is everywhere; the Earth’s atmosphere contains 21% oxygen. However, the amount of oxygen that dissolves into your wine is influenced by several factors. These include temperature, atmospheric, and pH.

There are several ways that oxygen typically enters wine during the winemaking process:

Crushing and pressing of the grapes: The physical removal of the grape’s skins and stems can increase the amount of oxygen absorbed into the juice.
Fermentation: Wines go through a pump system to remove the skin and seeds which increases oxygen levels. Often, oxygen is added during fermentation to stimulate the process.
Racking/pumping/filtration: As wine is manually moved from one container to another, atmospheric oxygen is naturally absorbed via the filtration pad’s porous membranes. A wine that is transported via mechanical pumps can also allow oxygen absorption into the wine.
Aging wine in a cellar: Wine aged in a cellar is contained in wooden barrels or stainless steel chambers. Although wood is non-porous, if the wood has not been treated it can lead to slow introductions of oxygen.
Bottling wine: When bottling your wine, you must pay close attention during final filtration and filling the wine bottles. This is typically the last stage where oxygen can unintentionally enter the wine.
Aging the bottle: If oxygen is trapped in the bottle’s headspace it can result in wine spoilage. Therefore, select your closure style wisely. Although they do not give your bottle of wine that ‘authentic’ look, screw-top bottles allow very little oxygen into the bottle. If you prefer to use a natural cork, select a high-quality cork. We recommend avoiding synthetic stoppers as they have the highest rate of oxygen influx into wine bottles.

How Does Oxygen Affect The Quality Of Wine?

When it comes to wine, the term “dissolved oxygen” is often used to refer to the amount of oxygen that is present in the wine. Depending on the concentration of dissolved oxygen, it can either improve or harm the wine’s quality.

On one hand, oxygen is necessary for the development of certain desirable flavors in wine. During fermentation, a small amount of oxygen can help the yeast cells to take in more glucose molecules, and as a result, it produces certain aroma compounds in the wine.

Additionally, a controlled amount of oxygen exposure during aging can help to soften the tannins in red wines, resulting in a smoother and more balanced flavor profile.

However, too much DO can be detrimental to wine quality. Excessive exposure to oxygen can lead to oxidation, which can cause a loss of color, flavor, and aroma in wine. Over time, oxidation can also lead to spoilage, resulting in off flavors and aromas that make the wine undrinkable.

Oxygen in wine can also affect the chemistry of the wine. For example, high levels of DO in wine can lower antioxidants, increase the formation of acetaldehyde (which can result in a rotten-apple aroma), and allow unwanted bacteria and yeast to thrive causing microbial spoilage.

The Benefits Of Limiting Oxygen In Wine

While oxygen is essential for the aging process of wine, too much of it can lead to spoilage. This is where limiting oxygen in wine comes into play. By controlling the amount of DO in wine, you can enhance its flavor, aroma, and longevity.

The benefits of limiting oxygen in wine are numerous. Firstly, it prevents oxidation, which can cause a wine to lose its freshness and develop unpleasant flavors such as vinegar or sherry-like notes.

Secondly, it helps preserve the wine’s color. Oxygen can cause the color of red wine to fade over time, leading to a loss of vibrancy and depth. By limiting oxygen exposure, winemakers can retain the wine’s rich color and visual appeal.

Limiting oxygen in wine also helps maintain the wine’s aroma and bouquet. Aromas are an important part of wine tasting, as they add to the overall sensory experience. However, overexposure to oxygen can cause these aromas to dissipate.

How To Eliminate Oxygen When Bottling Wine?

One effective way to eliminate DO is through the use of inert gases like nitrogen or argon. These gases are heavier than oxygen and can be used to displace oxygen from the headspace of the bottle. This creates an oxygen-free environment that helps preserve the quality of the wine.

Another method for reducing DO is through a process called sparging. Sparging involves bubbling an inert gas through the wine as it’s being bottled. The gas displaces any remaining oxygen in the bottle, creating a more stable environment for the wine.

When To Measure Dissolved Oxygen In Wine?

There are a few critical stages when you should measure the DO level in your wine.

The first is when you are racking your wine or there is going to be any tank movement. You also want to measure DO before and after wine filtration.

Dissolved oxygen must also be measured throughout the wine’s aging process, after processing, and before you bottle your wine. Finally, you must measure the DO level once you have bottled your final product.

Monitoring the DO levels at different times during the winemaking process not only ensures you have fine-tasting wine, but also benefits equipment efficiency during the wine production process.

How To Measure Dissolved Oxygen In Wine?

Monitoring dissolved oxygen levels in wine is essential for ensuring quality. Most modern wineries use specialized tools such as dissolved oxygen meters to measure the amount of oxygen present in their wines. These meters use a probe/sensor to measure the concentration of DO in the wine sample, giving winemakers an accurate picture of how much oxygen is present.

By monitoring DO levels regularly, winemakers can adjust their production processes accordingly and ensure that their wines maintain their quality over time.

There are several methods for measuring oxygen in wine, but the most common method is using a dissolved oxygen meter. A dissolved oxygen meter is a device that measures the amount of DO in the wine. The meter works by using a probe that is inserted into the wine, and it measures the amount of oxygen present in the wine.

Another method for measuring oxygen in wine is using a redox potential meter. A redox potential meter measures the wine’s potential for oxidation by measuring the electrical potential between two electrodes. The redox potential meter can give winemakers an idea of the wine’s potential for oxidation, but it is not as accurate as a dissolved oxygen meter.

Selecting The Correct Oxygen Probe

As you need to measure the dissolved oxygen level throughout the winemaking process, you will likely require more than one sized oxygen probe.

When your wine is in larger containers you will need an oxygen probe such as our Industrial Dissolved Oxygen Probe. Our Industrial Dissolved Oxygen Probe comes with an integrated temperature sensor, so you can measure the wine’s temperature at the same time.

Later on, you will need to measure the oxygen level inside the bottle. For that, you will have great difficulty trying to insert the Lab-Grade DO Probe. Therefore, a probe with a thin-body design like the Mini Lab-Grade DO Probe will be better.

At Atlas Scientific, our DO meters are portable and highly accurate, ensuring you have reliable measurements throughout your winemaking experience!

Best Practices For Measuring Dissolved Oxygen In Wine

One of the best practices for measuring oxygen in wine is to calibrate the equipment regularly. Calibration ensures that the equipment is providing accurate measurements, which is critical to producing high-quality wine.

Another best practice for measuring oxygen in wine is to take multiple measurements throughout the winemaking process. By taking multiple measurements, winemakers can get a more accurate picture of the wine’s oxygen levels.

A Guide To Measuring Oxygen In Wine In The Tank/Container

Before diving in, always refer to the DO Sensor User Guide for detailed instructions on how to assemble and prepare the sensor.

Assemble the probe according to the user guide and place the DO probe in the calibration sleeve and wet it with deionized water.
Turn the DO meter on and set the units to mg/L.
After calibration, the DO sensor should read a saturation of 98-102% when in the calibration sleeve – allow 2-3 minutes for the sensor to stabilize.
Thoroughly rinse the sensor with deionized water and dab-dry it with a lint-free cloth before placing it in the calibration sleeve.
After each measurement, the sensor must be rinsed and dried.
Now you can go ahead and measure the DO from directly inside the tank. This is done directly as wine samples cannot be preserved and movement of the sample can increase the amount of dissolved oxygen in the sample. However, if you need to move a sample, do so carefully and contain it in an air-tight container that has no air space. You must also ensure it is filled with no air spaces.
After preparing the calibration sleeve, insert the DO probe.
Perform an air calibration until a stable saturation reading of 100.0% is displayed.
Rinse the sensor again with deionized water and dab it dry.
Insert a stainless steel sensor guard around the sensor if you are taking the DO measurement below the tank surface. This allows it to sink to the desired depth.
Insert the DO sensor into the tank.
Wait until the sensor is fully stabilized to take the reading. The DO sensor will also record the temperature at this stage.
We recommend repeating the measurement once or twice so you can take the average.

A Guide To Measuring Oxygen In Wine In The Bottle

Steps 1 to 9 are the same as measuring dissolved oxygen in the tank (listed above), however, no sample preparation is required, as the DO can be measured directly in the wine bottle.

Submerge the DO sensor into the wine bottle. The silicone ring on the sensor should make a seal on the neck of the bottle.
Lie the bottle on the side so the neck becomes flooded.
Initiate the meter reading, allowing it to stabilize.
Like measuring the DO in the wine tank, we recommend taking more than one reading.

Summary

Measuring oxygen levels in wine is an essential part of the winemaking process and can have a significant impact on the quality of the final product. Winemakers need to manage the level of oxygen in the wine to ensure that it is at the optimal level for the specific wine style they are producing.

If you have any questions about the dissolved oxygen of your wine, or which dissolved oxygen probe you need for the winemaking process, do not hesitate to contact the world-class team at Atlas Scientific.