The syrah was sensational. I bought a case. A couple of weeks later I opened a bottle. It was pretty good. But not sensational.

Was I duped? Did the wine I originally tasted change? What went wrong?

In fact, my reaction to the second bottle relates more to any number of factors related to two simple facts:

1. Wine is a living product and changes imperceptibly.

2. We are not machines; we differ from day to day.

There are other factors that affect how a wine tastes on a given day, which makes the act of wine evaluation anything but a science.

The aforementioned syrah was first tasted in a blind setting and my first reaction was more amusement than love. Only after I tasted the wine for 20 minutes did I realize its greatness. The next time I tried it, I sought instant verification of its quality -- which was not how I viewed the wine the first time. Once the second bottle was open for a half hour, I again saw what I first had seen.

Also I recalled the odd concept of bottle variation -- that mystical notion that in a case of wines, you can have as many as 12 slightly different wines. Think of how many ways a bottle of wine can vary (very minutely) from its brethren.

The cork can be tainted or creased and alter the wine.

A white wine bottled in a clear glass bottle can pick up a slight skunkiness if left in direct light for even a short period of time.

One bottle can develop a curious smell because of a minor yeast problem while others do not.

Slight variations in aeration can radically alter how a wine smells.

The same wine in different shaped glasses can smell different from one another.

One day goes well: the accountant says you owe no taxes for last year, your kid just got straight A's, and your favorite baseball team just completed a three-game sweep. And a favored wine tastes great. Days later, you get a flat tire on the freeway, you miss a vital business meeting, you get a bad cold and a traffic ticket, and you sprain an ankle. And that same wine doesn't taste as great.

So-called great wines often taste terrible when you are with people you don't want to be with; so-called mundane wines can taste fine when you're having a great time with wonderful people you like or love.

All the above scenarios are based around a short time frame. Now look at how wines differ when tasted months or a year apart.

As a living product, all wines go through stages. When young, they're based on fruit aromas and offer little complexity. Later (months for most white wines, years for many reds), a wines' fruit has declined, but the complexity rises.

If you like complexity in wine, you may like them more mature. But if fruit is all you buy wine for, you may dislike complexity because it means you have gained something you can't understand and lost something you like.

Is the wine worse than it had been? Sure, to you it is. But those who love complexity may well be happy to take your less-than-fruity wine off your hands.

So in a certain way, stating that a wine is "great" requires you to state why you think so. Saying "I love it, so it's great" is no justification at all.

Will all young wine that an expert says is great remain great? The foregoing proves that the answer is most assuredly no. It will change. This will please some and irk others.

And is expensive wine better than cheap wine?

The late British author H. Warner Allen answered this question eloquently in one of his books: "The wines that one remembers best are not necessarily the finest that one has tasted; the highest quality may fail to delight so much as some far more humble beverage drunk in more favourable surroundings."

Wine of the Week: 2012 Fairview Goats do Roam, Coastal Region ($10) -- Charles Back of South Africa has a quirky sense of humor, and his line of excellent wines includes many fanciful names that are tweeks at the French. This wine, whose pronunciation is sort of like C?es du Rh?e, is patterned after a Rh?e Valley white with Viognier and Rousanne as its heart. It has excellent fruit and is as good as some similar wines that sell for two or three times the price.

Dan Berger lives in Sonoma County, where he publishes "Vintage Experiences," a weekly wine newsletter. Write to him at winenut@gmail.com.