Education
“Roll Our the Barrel” First Verse
by Stephen Pavy
I am often asked where all of the various aromas and flavors come from in wine. The wine tasting sheet for the St. Francis 2002 Sonoma County Merlot reads: “red plum, cherries, nutmeg, vanilla, lively acidity…” Do we “put” those flavors in?
We don’t (and it is not a silly question. No question about wine is silly, in my opinion.) But where do these aromas and flavors come from?
The aromas and flavors in wine come from three places, basically. First, they come from the grapes and vines themselves. In brief, certain varieties of grapes can produce certain aromas and flavors. Depending on where the vines are grown, the type(s) of soils they are grown in, how much water they get, how much sunlight, what the temperature is (during the day; during the night), what the cultural practices in the vineyard are (cover crop? Disked earth? Fertilizer?), canopy management….all of these things can change the subtle flavors and aromas in the grapes. The French have a nice word for all of these things (and more!): terroir. I’ll talk about this in an upcoming article.
Secondly, aromas and flavors come from the fermentation process. Again, in an upcoming article I’ll talk about de-stemming and crushing versus whole cluster pressing, free run juice, carbonic maceration, cold soaking, native yeasts, selected yeasts, and malolactic fermentation. The entire process of changing grape juice to wine is complex and involves many choices – all of which can change aromas and flavors.
But today we discuss barrels – the third place in winemaking where aromas and flavors can be introduced into the wine. Some wines don’t see barrels. Fruit-driven white wines, like a crisp Sauvignon Blanc, may be fermented in stainless steel and held there until ready for any cold stabilization, heat stabilization, fining, filtering, blending and bottling. But many varietals of wine typically see oak barrels, especially Chardonnay and most red wines.
Three basic changes occur in a wine as it matures in a wooden barrel: 1) alcohol and water evaporate through the sides of the barrel, concentrating the wine; 2) some oxygen dissolves in the wine, allowing oxygen-dependent maturation reactions to occur slow (micro-oxidation); and 3) substances from the wood are extracted out into the wine. Regarding this third change – extraction from the barrel – much depends on the type of barrel (size, species of wood, location of tree/forest), the cooperage (those who make the barrels), and the amount of toasting the barrel has received, time in the barrel and percentage of wine that is barrel-aged. All of these things can make the barrels impart different aromas and flavors, including cream, vanilla, toffee, butterscotch, caramel, brown sugar, nutmeg, mace, cinnamon, clove, anise, cedar, dill, toast, smoke, etc…and the list goes on. Wine also extracts additional tannins from the barrels during aging. So in addition to the tannins found in wine, putting wine in a barrel will add additional tannin structure to a wine.
Let’s finish this month’s article looking at white wines. All of our St. Francis Chardonnays are actually fermented in the barrel. Primary fermentation (changing the sugars to alcohol and CO2) is actually started in stainless steel tanks and then the fermenting juice is pumped over to individual barrels. It is easier to start fermentation in a temperature controlled tank and in a large quantity than it is to start fermentation in each individual barrel. What is amazing is that Chardonnay fermented in the barrel actually makes the wine less oaky tasting than if the wine were fermented in stainless steel and then moved to the barrel for aging (the wine kept in the barrel for the same amount of time). Why? The answer is complex, but barrel fermentation shifts the flavor extraction towards the flavors of vanilla, toffee, and caramel instead of the woodier flavors that would be extracted if the wine were merely aged in the barrel.
Our Chardonnays also undergo malolactic fermentation where we change the sharp, crisp, tart malic acid to a smoother, softer, more buttery lactic acid. This secondary fermentation happens in the barrels after the primary fermentation is completed.
Our Chardonnays are also aged sur-lies, which involves periodically stirring of the lees (yeast cells, other solids) that have settled to the bottom of the barrel. This process greatly increases the viscosity of the wine and enhances the mouthfeel and finish. For our Sonoma County Chardonnay, we keep this wine in the French and American barrels for about six months. For our Behler Reserve Chardonnay, we keep this wine in French barrels exclusively for nine to ten months.
Next month: “Roll out the Barrel”, Second Verse, where we will discuss “lactones” and other compounds that barrels contribute to winemaking and the role of barrels (pun intended!) in making red wine.
Read second verse
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