# **Flavor-aroma interactions in wine** In this blog post, we'll take a look at flavor-aroma interaction in wine. That is, how perceived flavors and aromas are impacted by changes in temperature as well as chemical interaction effects. Many of you may have discovered this yourselves in different ways. One example is when making lemonade for your kids finding the taste too sour and adding more sugar. When you did that, you didn't actually reduce the pH of the aqueous solution but **[the lemonade undoubtedly tasted less tart](https://mailchi.us2.list-manage.com/track/click?u=ad81412d881a69b363ccb8b44&id=239135c027&e=89e0fc70b6)**. This is an example of an interaction effect with sugar "masking" the perception of acidity while the pH level remained exactly the same.  Temperature Effect Warming: If you serve wine at warmer temperatures, you will increase the perception of any wine defects as well as increase the perception of ethanol making the wine appear as if it is having a higher alcohol level. Cooling: If you chill wine, you will conversely hide moderate wine defects and the wine will appear less alcoholic. So if you have a 16%+ ABV bottle of wine from Napa Valley or The Barossa Valley, and you find that too high on alcohol, try serving the wine at a lower than usual drinking temperature. The same thing happens as when you were drinking ice cold shots in your youth - the cold serving temperature will make the beverage appear less alcoholic. The same goes with benign wine defects. If you chill the wine to a lower temperature, you may find the wine passable for drinking rather than pouring it straight down the drain. Wine defects, as well as flavors and aromas, in general become muted at lower tempetatures. In addition, lower temperatures, reduce the sensitivity to sugars so cooler wines will also taste less sweet. So chilling the wine is a useful "hack" in case you find the wine too sweet. On the other hand, lower temperatures, will increase the perception of acidity, bitterness and astringency. So if you are drinking too young red wine, high on those attributes, you may want to be careful to not serve it too cold. Sugar Effect Sugar (i.e. glucose and fructose in wine) is a magic weapon for winemakers as well as for much of the food and beverage industry in general. Higher levels of sugar decrease the perception of acidity, astringency and bitterness. So a little bit of residual sugar in tannic red wine, will make it significantly more accessible at a young age as the wine drinker will not feel that the wine needs to age for any significant time for the astringency, bitterness and acidity levels to become reduced. This is a secret well known to Napa Valley winemakers who often opt for a somewhat sweeter style compared to their Bordeaux counterparts. And consumers react with their approval, with many feeling that they can drink their Napa Valley Cabernets young while their Bordeaux reds need to age. And now you are equipped with the tools to understand why. The higher sugar levels common in Napa wines simply make them more accessible at a younger age by masking acidity, astringency and bitterness. And this is why many quality Bordeaux wines are often unapproachable in their youth. Acidity Effect Higher acidity levels, decrease the perception of sweetness in wines and also decrease the perception of body in the wine. And higher acidity levels also increase the perception of astringency and bitterness. This makes high acidity levels particularly troublesome for red wine makers intent on making red wine for early consumption. And it leads winemakers down the pathways of either reducing acidity (e.g. through the application of potassium bicarbonate or calcium carbonate - effectively a Gaviscon-like treatment for the wine) or by masking the high acidity levels with residual sugar as per the above. The latter is the same effect as making lemonade appear less tart by sugaring it up despite the pH level of the aqueous solution remaining the same. Many of the 2018 private label wines much beloved by our wine club members have clearly been made by winemakers knowledgeable about this and that is why those wines are so accessible even at a young age. Ethanol Effect Higher ethanol levels increase the perception of sweetness as well as of bitterness while it suppresses the sourness of some acids and reduce the astringency of tannins. So here we get other clues as to why red wines from Napa Valley are often more approachable at a young age compared to red wines from Bordeaux. The alcohol level is often higher in Napa Valley red wines and this increases the sweet sensation. And sweetness in turn reduces the perception of acidity, astringency and bitterness. So the Napa Valley combination of high alcohol levels, together with a bit of residual sugar, really works wonders in terms of making otherwise highly acidic and astringent red wines approachable much earlier than many red wines from Bordeaux. Or as Tim Patterson **[wrote](https://mailchi.us2.list-manage.com/track/click?u=ad81412d881a69b363ccb8b44&id=79906336ba&e=89e0fc70b6)**: "elevated alcohol and perhaps a pinch of residual sugar mask the massive tannin levels in many high-end California Cabernets." The above should have given you a deeper understanding of interaction effects of flavors and aromas as well as insights into why quality red wines from Napa Valley are often more approachable at a younger age than the wines of Bordeaux. Equipped with this knowledge, you can shine at dinner parties and make the jaws drop of a sommelier or two. There are other effects worth discussing as well including what happens to tannins as wine age, impact of oak barrel treatment and micro-oxygenation of wines. These factors all affect flavors, aromas and mouthfeel of wines but they go beyond flavor and aroma interactions so we'll will save them for future blog posts.