If you buy a bottle of wine on Friday to drink during the weekend, sticking it on the kitchen counter or on top of the fridge is not a problem. If you buy a bottle of wine on Friday and intend to save it for six months or a year or more, I would rethink that storage method.
The vast majority of wines are meant to be consumed young. Storage is less of a big deal for wines that will be consumed within a few weeks of purchasing.
For those wines that you intend to hold on to (see my sections on choosing age worthy wines and cellaring), it would be worthwhile to be mindful of keeping them in good condition.
The enemies of wine for long term storage are: temperature fluctuation (particularly heat), light exposure, vibration, and dried cork (from low humidity, in general, though I will talk about how else this can happen). As you can imagine, sticking a valuable wine that you intend to age on top of a refrigerator (hmmm, let’s see: it can be warm on top of fridges, which give off heat; unless there is a cabinet there it will have light exposure; tons of vibration; and humidity is often low in kitchens). Not the right place or conditions.
Let’s talk about top closure of wine for a minute. Most wine (especially age-worthy wine; though inexpensive wine bottles are more likely to have screw caps) has a top closure made out of cork, an amazing substance found in nature from cork trees. These are great—but—wine with cork closures need to be kept on their sides. It isn’t, as it turns out, just for looks. Wines with corks are kept on their sides because this keeps the wine inside the bottle in contact with the cork, which helps to maintain the moisture level of the cork and prevent it from drying out. What’s the big deal about not letting the cork dry out? If the cork dries out, it can crack or develop holes in it, which can lead to oxygen getting inside the wine. The effect of oxygen on wine is to age it. Get enough oxygen into a good bottle of wine and it can prematurely age it, leading to everything from color change (red wines lighten in color and white wines darken—some amount of this is a natural part of the aging process of the wine and expected in very aged wines, but too much too soon is a sign that something bad has happened), to flavor change (again, some of these flavor changes can be a natural part of the aging process and in wine tasting parlance are called “tertiary flavors,” the presence of which are expected in truly aged wines, but too much too soon is a sign that something unfortunate has happened to your wine), and ultimately, to the wine being out of condition (just plain old and gross). Keep those bottles on their sides!
What about sticking it into a pantry or other closed shelving? It helps with the light exposure problem and perhaps also the vibration, but it is doubtful that your kitchen is at the proper temperature for optimal storage—55 degrees Fahrenheit/13 degrees Celsius. Also, unless you store it on its side you will have that oxygenation problem.
What about sticking it in the refrigerator? Also not good. It solves the light exposure problem a bit, so long as you don’t open and shut your refrigerator too much. It isn’t too hot. However, refrigerators vibrate and, most importantly, they are drying. Remember, dry cork can lead to oxygenation and premature aging or even spoiling of the wine.
The best place for long term wine storage? In a temperature and humidity controlled, dim, vibration free wine storage in which bottles are kept on their sides!