Teran is a red wine made from a variety of Refosk grapes grown in the mineral-rich terra rossa soils of karst areas that have a particularly high iron content. Teran must is very rich in acids and quite high in sugar, but what gives Teran its particular flavour is lactic acid in combination with bivalent iron. To explain the special nature of this wine we must first discuss certain wine acids and minerals.
Both must and wine contain a number of acids: the slower the maturation of grapes, the higher the acid content. Wines from warm areas are therefore low in acids, and if too low, the wine tastes flat and dull. On the other hand, wines from northern regions tend to have an abundance of acids - which makes them fresh, but acidic if the content is too high. The acid that contributes most to the acidity of the taste is malic acid (this is the acid that makes most unripe fruit taste sour). Luckily for the northern winegrowers, a natural method for the reduction of acidity exists.
Bacteria of the genus Micrococcus can metabolize malic acid into lactic acid. This reduces the overall acid content - since 0.6 units of lactic acid are produced from one unit of malic acid - and affects the taste: the wine acquires a smooth, "buttery" flavour (lactic acid is the principal acid in milk and other diary products). The process is called "malo-lactic fermentation" and is essential for the production of northern wines such as the White Riesling from highly acidic must. It must be avoided in wines with low acid content such as Traminec. Malo-lactic fermentation is a delicate process that can proceed only under specific conditions and is therefore easily controlled.
Among many other minerals, must and wine contain salts of iron. In young wine, iron is mostly in the bivalent form Fe(II) - these salts do not spoil the taste, and Fe(II) is the only form that the human organism can absorb (and benefit from). But Fe(II) soon transforms into the trivalent form Fe(III) which if present in quantity makes the wine bitter and spoils its colour. Special chemical procedures (for example, fining with potassium cyanide) must be undertaken to remove the excess iron.
One could say that Teran violates all of the principles described above. Although grown in a very warm climate - during the summer, the Kras area is scorching - it nevertheless contains ample acids; in fact, Teran must can have even more acid than Sipon. Furthermore, the terra rossa soils provide for a high iron content. In Teran, malo-lactic fermentation starts immediately after the fermentation of glucose is completed and proceeds quickly and vigorously until almost all the malic acid is converted into lactic acid - Teran can contain up to 3.5 grams of lactic acid per liter. Also, the specific mineral and acidic environment of Teran retains iron in its bivalent form much longer - up to two years after fermentation even with the traditional process.
Teran is a dark ruby-red wine - traditionally, it should be "black as rabbit's blood"; the extended maceration required to produce such a dark hue is considered exaggerated today. Teran is a wine that one either loves or rejects at first sip. It is a full-blooded wine (no pun intended!), rich in extract with a special, velvety taste and a pleasant earthy bouquet; its predominant and characteristic fragrance is raspberry. The "aged" taste is complemented by a spectrum of fruity hues and aromas: very pronounced blueberry and detectable aromas of raspberry and blackcurrant. Teran is very aromatic, rich with acids, tannin, and extract, but still balanced - a wine with a strong personality.
This wine is a great appetizer and has always been appreciated for its medicinal properties. Some oenologists believe that Kraski Teran is the Roman puccinum (for veracity's sake we must mention that others believe puccinum to have been a white wine similar to Prosecco). Pliny wrote that Livia, the wife of Emperor Augustus, drank only puccinum and lived to the respectable age of 82. The medicinal properties of Kraski Teran have been confirmed by modern day medicine: lactic acid stimulates the appetite and facilitates digestion of fatty foods; more importantly, Kraski Teran contains substantial quantities of bivalent iron.
Traditional Kraski Teran does not age well - notably, chemical analyses have confirmed that the content of bivalent iron starts to diminish radically two years after fermentation - and should be consumed within its first year; after that, the wine quickly loses its attractive vitality and can even become bitter and flat.
Kraski Teran is only cultivated in the Kras area of Primorje.
Kraski Teran and prsut (prosciutto or air-dried ham) are the legendary pair of Kras cuisine, but the wine is also perfect with other pork dishes, sausages, or boiled ham with horseradish. Kraski Teran should be served at 15 - 16 °C (59 - 60.8 °F).