Sip, swish, savor. However you enjoy your wine, it's great to understand that complex science shaping your drink, to either simply add to your knowledge, or surprise and impress your friends at the next dinner party.
For winemakers, there's a lot of thought that goes into creating the smell, mouthfeel, taste and aftertaste of wine, all beginning with growing the grapes themselves. The type of grape used is perhaps the most important choice—that's why wines are identified by their specific type of grape. But the geography of where those grapes are planted also matters. Since plants absorb all kinds of minerals and nutrients from the earth they grow in, local soil makes a big impact, as does the local climate.
Kids may love grape juice, but adults prefer wine — and that very important transformation from juice to wine is called fermentation. It happens because of yeast, the same type of microscopic critter that helps bread dough rise. Over the course of a few weeks, yeasts eat up sugars in the grape juice and convert them into alcohol.
Every strain of yeast works a little bit differently, affecting the taste as well as the alcohol content, so winemakers choose their yeast carefully. One may use naturally-occurring yeasts already present on the grapes, because while these wild yeasts are less predictable, they also give the wine a unique local flavor. Another winemaker might buy a specific strain from a distributor, because they want the specific attributes of that yeast, and a little more control over the process.
The next step is aging. While some people might want to stay young forever, the aging of wine is something we can all appreciate. Like any other natural liquid, such as milk or honey, wine is a complex solution of water, sugars, acids, minerals, and of course alcohol. These compounds slowly react with each other over time, which has positive effects—if the timing is right.
Some wines, like White Zinfandel, do better with almost no aging, while others, like Cabernet, are best if aged for a few years. Some, like Port, improve after decades of aging, but every wine has a limit past which the flavor starts to degrade rather than improve.
Over the course of the fermenting and aging process, samples of wine are also often analyzed in a lab. This helps winemakers understand exactly what's going on in their wine at a given time, so that they see how the finished result got to where it is. That way they can make adjustments to the process next time, like using a different yeast, or fermenting or aging for more or less time.
Once the last sample has been collected, the wine is clarified, removing the last of the yeast and any bits of grape that may still be there. This is the last chance the winemaker has to control the flavor, by using special filters to remove any specific, unwanted flavors.
Finally: the best and last step. The wine is bottled up to be further aged or sent straight out to stores and restaurants, and straight into your glass.