Craig Suveg on What Makes Hungarian Oak Unique

We began using Hungarian oak in 2010. In fact, historically, Suveg Cellars used Hungarian oak exclusively until 2014 for several varietals including Cabernet Sauvignon, Syrah and Sangiovese.

Since 2015, we have used combinations of wood both new and neutral sourced from France, Hungary and Russia. Personally, I have always found the art of coopering wine barrels and the use of different species of oak for aging specific wines particularly fascinating and an integral part of the process in crafting our wines.

But what makes Hungarian oak unique?

The oak forests and stave mills of Hungary account for approximately 4% of world wine barrel production. While less expensive than their French counterparts that average greater than $900 each, Hungarian oak barrels average just under $800 and remain generally more expensive than American oak barrels, which average about $500 apiece.

Hungary’s geography and climate differ significantly from that of France and, more importantly, Hungary’s native oak species differ completely from those of North America.

Quercus robur vs. Quercus petraea

The two main European oak species used for barrels are Quercus robur, also known as pedunculate oak and Quercus petraea, also known as sessile oak. The trees appear somewhat different, especially their acorns. Acorns on the Quercus robur are attached to branches by a little stem or pedicle, hence the name pedunculate. By contrast, acorns on the Quercus petraea sit directly on the branches. Hence the name sessile, which refers to sitting.

In my experience, petraea produces barrel staves that provide a pronounced aromatic character and low tannin content to a wine. Robur provides fuller body and more tannin structure will giving less complexity and less elegance than petraea. American oak barrels use Quercus alba, or white oak, to which many winemakers attribute a sweet, spicy, vanilla-like character. American oak has never been part of our barrel profile or inventory.

The two European species grow in various parts of Europe, often intermingled. Few forests have a high majority of one or the other species. The Limousin forest in south central France is one of those: its oak population is practically 100% robur. Another French forest, the Troncais, located in the exact center of France is unusual in having a high proportion of patraea oak. However, the Zemplen forest in the mountains of northeast Hungary near the winemaking region of Tokaj tops Troncasis with 95% of the oak trees being patraea. The Zemplen forest is absolutely unique in being so Quercus patraea dominant. Suveg Cellars is proud that the majority of its total Hungarian oak profile is sourced from this specific forest. The next time you visit the winery, a look at the barrels will reveal patraea on a number of the barrels.

The two European species prefer different living conditions. Robur performs best with more water, richer soil and more nutrition and seems to provide a more pronounced flavor to wine. Actually, the Latin based name robur means stronger, more robust. Petraea can survive and grow with fewer amenities in thinner soil, colder temperatures and during longer winters. In fact, the root meaning of the word petraea refers to rocks.

The Zemplen forest covers the foothills of the Carpathian Mountains where the best cooperage oak grows at somewhere between 1,200 and 2,100 feet elevation. This region has also had recent volcanic activity; between 6 million and 8 million years ago, meaning that some of the youngest volcanic flows in Europe are located in the Carpathians which reach 11,000 feet in some places.

Because of the difficult growing conditions, patraea trees grow very slowly and the wood grain is very tight, a trait almost universally considered desirable for aging high quality wines. The petraea trees in the Zemplen forest are generally harvested at 80 to 120 years old.

Wood grain is determined by the thickness of the growth rings. Each growth ring consists of a portion of early season growth and later season growth. Petraea tress in the Zemplen forest are stressed for nutrition and water and grow mainly in the early season. In general, the tighter the grain the more aromatic because all of the aromatics are basically in the early season or spring wood. Summer wood tends to be somewhat more structural and serves as merely “extra wood” and actually dilutes the aromatic impact of the spring wood.

When we speak of aromatics from Hungarian oak, we think in terms of two general aromatic compounds: eugenols and syringaldehydes. These two compounds impart cinnamon, clove and spice. By contrast, French oak imparts aromatic compounds of vanillin: vanilla, guaiacol and methylguaiacol: smoke and char, furfural: sweet oak, butterscotch, carmel and almond and lactones: fresh oak and coconut.

How exactly are these specific aromatic compounds produced? First, oak barrels are toasted – not charred! Whiskey barrels are charred. Toasting is done by open flame which mellows the oak’s harsh tannins and mitigates raw oak flavors. During the toasting process, the chemical bonds of wood sugars, primarily cellulose and hemicellulose as well as wood tannins are broken down in order to emit ellagic and gallic acids. Depending on the intensity and the exposure time of heat varying degrees of toast including light, medium, medium-plus and heavy are produced.

The most important difference between any oak barrel, whether new or neutral, French or Hungarian, light or medium toast is ultimately the flavor. We must remember that a wine barrel in its simplest form is an oxygen permeable storage vessel, the purpose of which is to permit controlled oxidation of the wine. This process in turn assists in stabilizing the wine’s color, varying the flavor, developing the tannin profile and texture.

While winemakers in North America had some disappointing experiences with Hungarian oak barrels during the 1990’s, those are now just memories fading into the past. A look at the forests and cooperages of this great and ancient winemaking country clearly demonstrates why Hungarian barrels have rightfully earned a place in the barrel programs of so many wineries today and are proudly featured in the wines crafted at Suveg Cellars.

Craig Suveg