As with any rating system, there is no such thing as a universal wine rating system.  Wines are rated by different wine clubs, groups, restaurants, food critics, magazines, and wine aficionados.  Just like movies may get good or bad ratings depending on the critic, the same wine may get a higher or lower rating depending on who is doing the actual rating.  Most wine rating systems work the same as any other rating system, awarding a number of points to a particular wine in a variety of categories.  Wine Spectator, a leading magazine about wine, uses a 100-point system when rating wines.  One you understand the different categories of how a wine is critiqued, you may be better able to understand the wine rating system you're perusing.

What is Usually Evaluated

Most who review wines evaluate it by more than just its flavor.  Texture and aroma are also important.  This is because these things are typically affected by the quality of the fruit that is used, the fermentation process, and the procedure used to make the wine.  A poor quality aroma or lack of texture can affect anyone's wine rating system, and quite a bit at that.  To better illustrate, imagine have a cup of coffee that tastes good but smells like dishwater, or that is as thick as mud.  Obviously the smell and texture of any beverage or food is important to the enjoyment of it, just as much as the actual taste.

How Evaluations Are Done

It's important for an impartial wine rating system that wines are stored properly before they're tasted.  They are kept at room temperature of 70-72 degrees Fahrenheit.  Most wines are sampled as soon as the bottle is poured, and then decanted and allowed to be set aside.  They may be re-tasted in 20 minute intervals, to evaluate any changes in the character and taste.

You may have seen a wine taster take a sip of wine or water and spit it out afterwards.  To be sure that there is no mixture of tastes and adulteration of the wine rating system, the taster may rinse his or her mouth with water and then spit that out.  They may also spit out the wine simply because ingesting it may affect the taste of the next sip of wine.

Can You Trust a Wine Rating System?

One wine expert stated on his website that evaluating a wine is much like relating what you see shaped by clouds.  Everyone is different and it's all very subjective and open to interpretation.  Think of a movie you saw that got great reviews, and you thought was a complete waste of time - or vice versa.  Wine rating systems are just like that; if you have the same taste and preferences as the evaluator, then you're likely to agree with his or her opinions.  If your tastes are different, your opinions will be different as well.  The best thing to do is experiment a bit with wine sample from a local winery and see which types appeal to your palate.