Which has more carbs, Merlot or Cabernet Sauvignon? A Nutritional Breakdown

October 15, 2025 •

4 min read

When considering which wine to enjoy, particularly while monitoring carb intake, many people question the difference between popular red wines. In fact, a 5-ounce glass of Merlot contains approximately 3.7 grams of carbohydrates, making it slightly lower in carbs than a comparable serving of Cabernet Sauvignon. This subtle difference is key for those following specific dietary plans, such as low-carb or ketogenic diets.

Quick Summary

This nutritional breakdown compares the carb content of Merlot and Cabernet Sauvignon, explaining why the difference is minimal in dry varieties. It also explores the factors that influence carb levels in wine, such as residual sugar and winemaking techniques, offering a comprehensive guide for wine lovers on a low-carb diet. Guidance on choosing other low-carb red and white wines is also provided.

Key Points

Slight Carb Difference: For a standard 5-ounce glass, Merlot has slightly fewer carbs (~3.7g) than Cabernet Sauvignon (~3.8g), though the difference is minimal.
Dryness is Key: The most important factor for low-carb wine is its dryness. Dry wines have less residual sugar and thus fewer carbs compared to sweet or dessert wines.
How Fermentation Works: Carbs in wine come from residual sugar, which is natural grape sugar not converted into alcohol by yeast during fermentation.
High ABV, Low Carbs: Higher alcohol content can sometimes indicate lower carbs because more sugar was converted to alcohol during fermentation.
Low-Carb Alternatives: Other excellent low-carb wine options include dry Pinot Noir (~3.4g), Sauvignon Blanc (~2-3g), and Brut Nature Sparkling Wine (<1g).
Check for Added Sugar: Some commercial wines add sugar for flavor, increasing the carb count. Quality, traditionally-made wines are less likely to have added sugar.
Serving Size Matters: The carb counts are based on a standard 5-ounce pour. Larger servings will increase the total carbohydrate intake.

Understanding Carbs in Wine: It's All About the Sugar

The carbohydrate content in wine is primarily determined by its residual sugar (RS), which refers to the natural grape sugars left over after the fermentation process. During fermentation, yeast consumes the grapes' sugar and converts it into alcohol. The longer the fermentation, the less residual sugar remains, resulting in a drier, lower-carb wine. Therefore, when comparing two dry red wines like Merlot and Cabernet Sauvignon, the carbohydrate difference is typically very small.

The Direct Comparison: Merlot vs. Cabernet Sauvignon

While the difference is slight, Merlot generally contains a fractionally lower carb count than Cabernet Sauvignon. For a standard 5-ounce serving, the carb counts are quite close:

Merlot: Around 3.7 grams of carbohydrates
Cabernet Sauvignon: Around 3.8 grams of carbohydrates

This marginal difference is unlikely to impact most diets significantly. The key takeaway is that both are excellent options for those seeking a lower-carb red wine, especially when compared to sweeter wines, which can have significantly higher carb counts due to higher residual sugar.

Factors Influencing a Wine's Carb Count

It's important to remember that these are average figures. A wine's final carbohydrate content can be influenced by several variables:

Sweetness Level: This is the most crucial factor. A "dry" wine has very little residual sugar, while an "off-dry" or "sweet" wine has considerably more, and thus, more carbs. Always opt for dry wines to minimize carb intake.
Alcohol by Volume (ABV): There's an inverse relationship between alcohol and carbs. Higher alcohol wines often have lower carbs because more sugar was converted to alcohol during fermentation. A wine with a higher ABV (e.g., above 13%) is more likely to be drier and lower in carbs.
Winemaking Techniques: Some commercial winemakers may add sugar post-fermentation to enhance flavor or sweetness, a process that can increase the carb load. Opting for wines from quality-focused producers can help avoid this.
Serving Size: The standard 5-ounce pour is the basis for most nutritional estimates. A larger glass will naturally contain more carbs, regardless of the wine type.

Low-Carb Wine Selection: Beyond Merlot and Cabernet

For those on a strict low-carb or ketogenic diet, exploring other wine options can be beneficial. Many dry varieties offer similarly low-carb profiles. Here are a few to consider:

Pinot Noir: A lighter-bodied, dry red wine, often cited as one of the lowest-carb red options, with around 3.4 grams per 5-ounce glass.
Syrah/Shiraz: A full-bodied dry red that remains relatively low in carbs, averaging 3.8–3.9 grams per 5-ounce pour.
Sauvignon Blanc: A dry white wine known for its crispness, with a carb count typically around 2–3 grams per 5-ounce glass.
Chardonnay (Unoaked): When unoaked and dry, this white wine is a good low-carb choice, with approximately 3–3.2 grams of carbs per 5-ounce glass.
Brut Nature Sparkling Wine: For those who prefer bubbles, this is the driest option available, with less than 1 gram of carbs per 5-ounce serving.

Comparison Table: Merlot vs. Cabernet Sauvignon


Attribute	Merlot (Dry)	Cabernet Sauvignon (Dry)
Carbohydrates (per 5 oz)	~3.7 grams	~3.8 grams
Flavor Profile	Softer, smoother, with red fruit notes like cherry and plum.	Bold, structured, with dark fruit flavors like blackcurrant and blackberry.
Tannin Level	Lower tannins, leading to a softer mouthfeel.	Higher tannins, which contribute to its structure and aging potential.
Acidity	Tends to have lower acidity.	Often has higher acidity, which balances the higher tannins.
Ideal for...	Those seeking a smooth, approachable red wine.	Those who prefer a more robust, complex, and age-worthy red wine.

Choosing the Right Wine for Your Nutritional Needs

For those monitoring their carbohydrate intake, the difference between a dry Merlot and a dry Cabernet Sauvignon is minimal and should not be the primary factor in your decision. Instead, focus on the wine's dryness and avoid varieties known to be high in residual sugar, like dessert wines, Ports, and many off-dry or sweet blends. The key is to check for a "dry" label or, when in doubt, choose wines known for their lower sugar content, such as Pinot Noir, Sauvignon Blanc, or Brut sparkling wines. As always, moderation is important when incorporating alcohol into a balanced diet.

Conclusion

In the debate over which has more carbs, Merlot or Cabernet Sauvignon, the answer is that Cabernet Sauvignon has a marginally higher average carb count. However, the difference is so small that it is virtually insignificant for anyone not on a strict ketogenic diet. For most wine lovers, the best strategy is to focus on selecting dry red wines over sweeter varieties to keep carbohydrate consumption to a minimum. By understanding the key factors that influence a wine's carb content—primarily residual sugar and winemaking techniques—you can confidently make informed choices that align with your nutritional goals.

Frequently Asked Questions

Merlot is typically slightly lower in calories than Cabernet Sauvignon. A standard 5-ounce glass of Merlot averages around 120 calories, while Cabernet Sauvignon is around 122 calories.

Among popular dry red wines, Pinot Noir is often the lowest in carbs, with an average of 3.4 grams per 5-ounce serving.

Yes, you can drink red wine on a keto diet, but it is important to stick to dry red varieties and consume them in moderation. The carb count in dry reds is generally low enough not to disrupt ketosis.

In many regions, nutritional labeling is not required for wine. This is largely due to tradition, though some brands are now voluntarily including this information. As such, you often need to look up average carb counts or stick to dry wines.

Yes, sweeter wines have significantly more carbohydrates because they contain higher levels of residual sugar. The fermentation process is often stopped early to leave more sugar in the wine.

Overall, the carb difference between dry white and dry red wines is minimal and often depends more on the specific varietal and production process. Some dry whites like Sauvignon Blanc and Pinot Grigio are excellent low-carb options.

The main factors are residual sugar (sweetness level), alcohol content, and winemaking techniques. Choosing a dry wine with a higher ABV and from a quality producer generally results in lower carb content.