Every week, Mark Oldman -- wine expert, acclaimed author and lead judge of the hit series The Winemakers -- shares with readers the basics of wine, while making it fun and practical. In the coming weeks, he'll tell you what to ask at a wine store, at what temperature to serve it and share his must-have wine tools.

My friend Carl is an apple-cider savant. If you put three different glasses of cider in front of him, after a few sips of each, he can tell you which one is from Gravenstein Apples in Sonoma, which originated in Canada and which came from the Jonagold apples of central New Jersey. This is because the taste of each cider reflects where the apples come from — their geography and growing conditions — so each possesses a distinct aroma and taste.

So the same goes with wine.  Enthusiasts often talk of a wine’s terroir (tare-WAHR), the consistently identifiable taste that reflects where the grapes came from. A terroir-driven wine expresses not only its grape type, but also all of the natural conditions in which those grapes were grown: the soil type, the angle of slope on which it was grown and the particular micro climate there. Certain wine types, like from France’s Burgundy and Alsace regions, are known to express their terroir — that is, these wines have a unique personality that conveys the natural conditions from which they came. They express a “sense of somewhere,” which is how the term “terroir” is often translated from French, though there is no precise definition in English.

While some winemakers focus on respecting a wine’s terroir, others like to tinker with nature, sometimes using excessive amounts of oak, over ripened fruit or other factors that might obscure a wine’s terroir. In these cases, the wine’s character expresses not a particular vineyard or region, but the decisions and desires of that particular winemaker.