Wine Fridges: Single Zone vs. Dual Zone Refrigeration

What makes a good bottle of wine? Some say it's the soil, some say the grapes, others claim it's the barrels the wine's aged in, but they're wrong. That's not that soil, grapes, and barrels aren't important, but none of them are nearly as important as temperature. Temperature determines how quickly a wine matures and how well balanced its flavors are. Chill a bottle of wine too long or leave it out in the hot sun for a couple of hours and you'll end up with an undrinkable mess. That's why wine makers spend so much time on climate-controlled wine cellars and why wine drinks spend so much money on wine coolers. Wine coolers are small refrigerators designed to keep wine perfectly chilled until it's ready to drink. There are several variations, but the most common are single zone wine coolers and dual zone wine coolers. Single zone wine coolers are pretty straightforward. You adjust the temperature up or down to the ideal storage range (normally 55°F) and leave it alone. A cooling system in the back of the unit pipes in cold air and keeps the temperature from spiraling out of control. Your wine stays cool and unspoiled until you're ready to pop the cork and drink it. Despite the simplicity of this system, single zone wine coolers are quickly being supplanted by a new innovation: dual zone wine coolers. Dual zone wine coolers offer the same level of cooling power, but better storage options. By dividing their storage space in half, dual zone wine coolers do a better job storing both red and white wine. They allow you to protect white wine from oxidation by storing it at a lower temperature and they make it easier to enjoy your red and whites at their optimal serving temperatures.

Oxidation & Dual Zone Wine Coolers

Regular readers know that wine isn't a static solution. It's a constantly evolving mixture of over 1000 different ingredients and chemicals, such as tannins, oxygen, alcohol, and esters, each reacting and interacting with one another. It's this complexity that gives the wine its rich flavor and what's at stake when you store it at the wrong temperature.

 

A lot of things happen to wine as it ages, but its biggest enemy is oxidation. As oxygen interacts with the wine's chemical solution, It flattens the rich, complex tastes you love. It leads to the development of aldehyde, an organic compound that gives wine a stale, acidic flavor, and it also encourages the growth of microbes that produce acetic acid, one of the main components in vinegar. Sadly, if you own a bottle of wine long enough, some degree of oxidation is inevitable. Eventually, a few oxygen molecules will eventually seep through the cork and into the wine. The good news is there are two ways to slow down this process. The first, tannins, is determined by the wine's chemistry. The second is determined by its temperature. Tannins are organic chemicals found in bark, seeds, leaves, and the skin of certain fruits, such as grapes. In wine, they attract and bind to oxygen molecules, creating long chains of molecules known as polymers. The more tannins a wine has, the fewer free oxygen molecules there are to oxidize. Red wine is packed with tannins because it's made, the juice is fermented with grape skins and seeds. It also absorbs more tannins from the oak barrels it's aged in. White wine, which is fermented without skins or seeds, has very few tannins and is thus a lot more vulnerable to oxidation than its red wine. Because it lacks any chemical protection, the only way to protect it from oxidation is to store it at a lower temperature.

 

The temperature a wine is stored at determines how much energy it has to fuel the chemical reactions inside of it. The rate of reaction doubles with every 18°F increase in temperature. Storing a bottle of wine at 73°F for a year is the equivalent of storing it for two years at the preferred temperature of 55°F, and soring it for a year at 91°F is the equivalent of four years at 55°F. So why are wine makers so careful about how they store wine? Why doesn't cranking up the temperature mature wine faster? Because not every reaction that takes place inside it has the same heat threshold. It takes less energy for tannins to polymerize, for example, than it takes for sugars and acids to ferment. For them, raising the temperature to 73°F is the equivalent of storing them for eight years at 55°F. It leads to a totally unbalanced flavor. The good news is that this process also works in reverse. Lowering the temperature of wine below 55°F slows the reaction rate, especially the rate of oxidation. (At 55°F, all of the reaction rates in wine proceed at roughly the same pace.) Because cooling a wine isn't nearly as harmful as warming it up, this is the best way to extend the lifespan of your white wine. Because red wines don't benefit as much from lowered temperatures, because of their tannins, this process is only recommended for white wines. Some red wines are actually strong enough they can be stored a little above 55°F without suffering any harm. This difference is the reason why dual zone wine coolers are so advantageous. They allow you to customize the storage temperature for your reds and whites while keeping them together in the same unit. Your wine stays fresh longer than if it were all being stored together at the same temperature.

Serving Temperatures & Dual Zone Wine Coolers

The temperature you serve wine at is just as important as the temperature you store it at. Temperature not only affects the wine's chemistry, but also your taste buds, specifically certain microchannels inside your tongue called TRPM5. They relay the electrical impulses to your brain that get interpreted as taste. These channels are much more receptive when they're warm than when they're cold. It's why hot food tastes so much better than cold food, and it's one of the reasons why wine should be served at a different temperature than they're stored. Drinking a wine that's too cold will make it taste weak and flat, while drinking a wine that's too warm will make it taste too strong The other reason is the affect temperature has on wine's flavor compounds. Chilling a bottle of white wine dampens its sweetness and gives the wine a crispy, fruity, savory taste. Red wines, on the other hand, taste better when they’re warmer. The elevated temperature makes the acids and tannins are less noticeable, giving the wine a smoother taste. Temperature also increases wine's volatility, the rate at which it evaporates and releases flavor compounds. The colder the wine, the less aroma it has. A wine's aroma is a major factor in determining how good it tastes. The human tongue can only detect five basic flavors: sweet, salty, sour, bitter, and umami (meaty flavors), but when we drink wine we detect a lot more. That's the aroma: the esters, aldehydes, and terpenes that fill up the head of the glass. They're responsible for the woody, nutty, spicy, and fruity flavors we enjoy whenever we have wine. The key is to make sure the wine doesn't become too volatile. Too many flavor compounds are overwhelming. You want to keep your wine in a narrow range, where they release just the right amount of aromas. Stray too far beyond it, and the wine won't present well. Here are the right temperatures for the most popular reds and whites.

Red Wines

Temperature

Beaujolais, Valpoliciella
Dolcetto, Cotes du Rhone, Merlot
Chinon, Port, Maderia
Chianti, Zinfandel
Rioja, Pino Noir, CDP
Barolo, Burgunday
Bordeaux, Cabernet Sauvignon, Shiraz

54°F
55°F
57°F
59°F
61°F
63°F
65°F

White Wines

Temperature

Sauvignon Blanc
Pinot Grigio
Semillon
Reisling
Chardonnay
Rosé
Pinot Noir

45°F
45°F
45°F
45-50°F
50°F
50°F
50-55°F

Getting your wine to the right temperature can be difficult, but dual zone wine coolers make it easy. Plug the storage temperature into one zone and the serving temperature into the other. Move bottles from the storage zone to the serving zone whenever you're planning to have a bottle of wine. After twenty or thirty minutes, they'll have warmed up to exactly the right temperature, guaranteeing you a perfect bottle of wine every time you drink.

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