SYDNEY — Judging wine, something I have done for more than 30 years, can be challenging or it can be fun. Mostly it's the former, combined with doses of frustration, aggravation, and pain.

Rarely is it the latter.

And the reasons for it being a not-so-easy task are numerous, starting with the fact that wine judges do not usually go into this activity looking for a lot of enjoyment. The mindset, when facing 55 dark red wines and their expected high tannins, is more survival than pleasure.

The best wine competitions to judge, for me, are those that are regional, where the wines come from a pre-determined area and where the styles of wine are at least partially predictable.

So I particularly like regional competitions, such as the recent Mendocino County Fair wine competition, staged in Boonville. There are a limited number of wines, their styles are based on a set of known parameters, and the judges are all relatively familiar with the region and what it does best (and not so well).

Importantly, the judges are asked to judge a manageable number of wines per day (say 60 to 90), allowing for a sane discussion of the wines before medals are agreed upon.

By contrast it's less easy to do a major wine competition in which judges evaluate wines from a wide range of places and at which some panels are asked to judge about 200 wines in a day (or more!), and where categories are not even broken up into smaller groupings.

I'll never forget the time not long ago when I was asked to judge 17 Viogniers, 90 Petite Sirahs, and 95 Syrahs on the same day. It was no fun. (And certainly not beneficial to the wines.)

I experienced another fascinating judging over the last week here in Australia. I was the lone U.S. wine judge at the Six Nations Wine Challenge, a contest pitting the best wines of Argentina, Australia, Chile, New Zealand, South Africa, and the United States against one another in 17 different wine categories.

Each of the six judges had to nominate no more than 100 of the best wines from their countries. After the wines were sorted into various categories, we were each asked to judge groups (none larger than 45 wines) and determine the best.

You could make an argument that the various styles into which each grape variety may be made differ widely enough that one from one area of Australia could be radically different from another area of the same country, let alone the differences between a wine from Capetown and one from the identical grape grown in Napa.

The confounding thing is that winemaking styles have become somewhat homogeneous worldwide in the last two decades, meaning that a lot of the wines I saw while judging last week could have been made in any of the six nations.

This is both a good and a bad thing. Without much distinctiveness, the wines all represented good drinkability, but what a number lacked was that regional diversity that once was such a major part of what we once knew to be a local style.

Certainly we all saw regional differences that set the wines apart. But since the tasting was double-blind, we could only guess which region a wine was from. As a result, the winner of each category would necessarily be the wine that, in the view of the six judges, best represented the grape variety, and has ultimate drinkability.

In the final analysis, one wine was determined to be the best in each category, which is, in a way, a leap of faith. In truth, six or eight wines were such strong candidates for the top award that there was almost no unanimity among the judges.

That was a good thing for the consumer. When the results of this event are reported in early October, the best wines in each class will be reported along with a number of additional double-gold medals as well as gold medals, giving consumers a wider choice of quality wines from which to choose.

We'll report the Six Nations winners here in October.

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