Absolutely Everything You Need to Know about Cabernet Sauvignon and Merlot

Posted August 07, 2015

Stacy Brody


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The King of Grapes & His Mistress in Satin

Two red wine grape varieties you know and love. They produce delicious wines and are grown worldwide. Their first home: Bordeaux, the famous winegrowing region on France’s Atlantic Coast.  

Bordeaux is bisected by the Gironde River. One variety dominates the Left Bank and the other, the right bank. Need a visual?

One is known as the King of Grapes, producing solid, structured, age-worthy wines.

The other is known for producing wines that are a bit more...come-hither. The king’s mistress in satin, if you will.

Cabernet Sauvignon and Merlot are grown around the world. You’ve probably tried dozens of wines made from these grapes. But, have you taken the extra time to stop and think about what makes them different and why they blend so perfectly together?

STOP. You’re going to do that right now.

The Grapes

The differences start in the vineyard. Cabernet Sauvignon and Merlot grapes, if you ever get the chance to see them at harvest (before they get crushed or stomped), are quite different from one another. Think about how much variation you can find among apples in the produce section of the grocery store - Gala and Red Delicious are both red apples, but they aren’t the same by any means.

Note: Wine grapes are much different from grocery store table grapes and much, much tastier. They have seeds. You deal with seeds because these small grapes are intensely flavored and yummy, in a word.

Cabernet Sauvignon grapes are small (even compared to other wine grapes). The skins are thick, and the berries have many seeds, which, in the wine world, are known as pips. Wine folks have to rename everything to make it more confusing. Whoever heard of calling grapes “berries” and seeds “pips”?

Anyway, in these thick skins, you find an abundance of anthocyanins - nature’s coloring agents. These molecules give red wine its color. Because the skins are so thick and the berries (grapes) so small, you get a high concentration of anthocyanins, which translates to deeply colored wine.

Also in the skins, as well as in the pips, are tannins. Have you tasted the bitterness of oversteeped tea or experienced a drying effect after drinking red wine? Don’t doubt yourself - you know what tannins are. Tannins are essential for pairing wines with rich foods like steak (more on that later) and give wine the structure and stability to evolve in the bottle. Because of the high ratios of pip to pulp (that’s a tongue twister!) and skin to pulp, Cabernet Sauvignon wines can be highly tannic when young and supremely age-worthy. Long live the king!

Merlot grapes, on the other hand, are a bit larger, with thinner skins, and a lower pip to pulp ratio (try saying that five times fast). This yields wines with fewer, softer, rounder tannins. A bit voluptuous, can I say?

Why did the grape cross the river?

Okay, bad joke. At least I tried.  

Both varieties are grown in Bordeaux and are classically blended in varying proportions. Cabernet Sauvignon is the predominant variety in blends from the Left Bank of the Gironde River (Margaux, Pauillac, St. Estephe), while Merlot is the predominant (sometimes only) variety in Right Bank blends (Pomerol and St. Emilion).

Why the difference? Left Bank vineyards are just that much closer to the Atlantic Ocean. Large bodies of water, i.e. the ocean, have a great moderating influence on the weather, preventing early spring frosts and delaying fall frosts. Cabernet Sauvignon needs a long season to ripen. If harvested underripe, it displays vegetal notes, like “green bell pepper.” With the influence of the Atlantic Ocean and a slightly longer season, Cabernet Sauvignon ripens more consistently on the Left Bank.

Farther from the ocean and its moderating influence, Right Bank vineyards can not consistently ripen Cabernet Sauvignon. Merlot, on the other hand, ripens two weeks earlier, and therefore does quite well on the far side of the river.

The Left Bank is also known for gravelly soils. You can thank the Dutch for that. In the 1600s, Dutch engineers drained the marshes that once covered Medoc and Haut-Medoc. Cabernet Sauvignon vines won’t tolerate “wet feet” (one thing Cabernet and I have in common) and thrive on sites with good drainage. Merlot vines are better able to tolerate the Right Bank’s damp soils.

Licking shoes and writing by hand

Cabernet Sauvignon-based wines are wines of structure. Remember the high ratios of skin to pulp and pip to pulp? While good structure is to be expected, heavy wine is not. The weight, or body, of the wine depends on the climate in which the grapes are grown. Generally, when grown in cooler climates, wines are medium-bodied, while wines from warmer climates are full-bodied. In Cabernet Sauvignon wines, you may find aromas of dark berries and blackcurrants, sometimes even leather. Not that you’ve ever licked a shoe or anything.

Merlot wines often display dark berry notes as well, bringing in a cocoa component (I want you to think very hard about the difference between chocolate and cocoa). They may also display a note like graphite or pencil shavings. Want to know one of the many reasons to preserve the art of writing by hand? So you’ll know how to identify this key descriptor.

Better together?

Blending is one of the many skills of a good winemaker, an art that often goes unnoticed. In the cellar, he or she decides the exact proportions of the blend, using varieties to complement one another, add richness and depth, fill in the gaps.

In Bordeaux, and, more and more often elsewhere, Cabernet Sauvignon and Merlot are blended together. You could think of it this way: Cabernet builds the house - gives structure, backbone, aging ability. Merlot fills the house, accentuates it, adds character. I didn’t discuss Petit Verdot, but you should know that it is another red variety grown in Bordeaux and used in Bordeaux-style blends, that enhances, enriches and deepens the wine. So if Cabernet is the house, and Merlot is the furniture, this could be, say, your curtains and paintings. Each variety adds another layer to the wine, bringing more complexity to your glass.

Bordeaux to the World

From their home in Bordeaux, these grapes have spread worldwide: Australia, Italy, Argentina, Chile, South Africa and the United States.Around the world, winemakers are following Bordeaux tradition and also experimenting with new blends.  In Australia, Cabernet may be blended with Shiraz. In Italy, both varieties may be included in Super Tuscan blends, alongside the region’s star grape Sangiovese. Please note: Wine is a living, changing thing, and varies with terroir, climate, and winemaker style. Their expressions in each climate and country are unique - but climate by variety interaction may be a topic best saved for another time.


Quiz time: what is essential for pairing with rich foods like steak?



… Time’s up. The answer: tannins. Better read more closely next time. ; )

Cabernet Sauvignon, with its characteristic tannins, pairs well with rich foods like steak and aged cheeses. Fat and tannin work well together. Think about an everyday application: Whole milk tastes good in coffee because the fat softens the bitter tannins. So sear a steak and pour a glass of richly structured Cabernet.

Merlot wines, with round tannins and softer acidity, pair well with pork dishes, medium-aged cheeses, and even burgers. Invite over some friends (or your favorite wine consultant) to enjoy a Merlot blend with young Cheddar and Manchego.

If they were a celebrity couple

So, now you know a little bit more about the grapes, the wines, and the blends. I’d like to know what you think. If Cabernet Sauvignon and Merlot were a celebrity couple would they be, as our New Zealand buyer Terry says, Bogart and Bacall? Or, would they be, as our Spain buyer Jeff suggests, Tracy and Hepburn?

What do you think? Have your own idea? Let me know.

Stacy comes to Wine Library from the production side of the industry. After studying agriculture in college, she found herself working at a local winery and, at harvest season, snacking on as many Pinot Noir grapes as she could take before the winemaker noticed. She enjoys reading, hiking, and scoping out what's in season at the local farmers' markets.

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