In time Z-23 has become the banished Princess, as it’s marketing “23 anos” became “23″ and the added sweetness apparent. But I’m posting to comment on the much misunderstood “solera” process.

Scotte’s description of the method is quite accurate, and you will note that most of the soleras – like Z-23 or Ron Matusalem – like to quote what was the oldest rum in the mix.

But average age is quite different.

Statistical anaylysis of a typical, four-level system reveals that the development of the “average” is the reverse of exponential, or logarithmic. In simple terms the average age increases for a few years, then tapers off.

Bottom line: it is very hard to much exceed an average age of about 8 years. The most good is achieved in about 4 years and four levels (roughly). Another notion: remember that the oldest rum in the blend (which is actually very little) gains a year, every year.

Thus a quoted “15 year solera” (like Ron Matusalem), should more accurately be called Matusalem 16 the next year, and “17″ the next, etc. By now Zacapa 23 should be called Zacapa 34. But the marketing department wouldn’t have that.

Trust me, they are all quite aware of the average age, but they aren’t saying. It’s 8 years or less, and that is not nearly as saleable.