Glossary

Herbaceous

"Grassy" describes green, herbaceous aromas reminiscent of freshly cut grass, green peppers, asparagus or stinging nettles. These are attributable to two different groups of compounds. The pepper note is attributable to methoxypyrazines, which occur naturally in Sauvignon Blanc, Cabernet Sauvignon, Cabernet Franc, Merlot and Carmenère; the note of freshly cut grass, on the other hand, stems predominantly from compounds produced when leaves and stems are damaged. Methoxypyrazines accumulate in the berry skins, seeds and stems between fruit set and veraison, and are subsequently broken down when exposed to light – shaded grapes retain significantly more of these compounds than sun-exposed ones. The concentration can therefore be controlled through canopy management and the timing of the harvest.

Whether this impression is characteristic of the variety or indicates incomplete ripeness depends on the wine: in Sauvignon Blanc it is part of the profile, whilst in a full-bodied red wine it is usually interpreted as a flaw. – SUPERIORE.DE

→ See also Green

Hyperoxygenation

Hyperoxygenation refers to the deliberate saturation of white must with oxygen prior to fermentation. This may seem counterintuitive, as oxygen is otherwise regarded as the enemy of white wine – but the mechanism is based on a difference between must and wine. In must, oxidation occurs enzymatically, triggered by polyphenol oxidases naturally present in the grapes. The resulting intermediate products combine to form larger molecules that no longer dissolve and flocculate. This is precisely the aim of the process: the oxidation-sensitive phenols are converted in advance and can subsequently be separated.

The browned must is therefore stripped of the flocculated phenols during pre-clarification – once filtered, it regains its normal greenish-yellow colour. What has been removed in this process is no longer available to the finished wine as a target for oxygen attack: it ages more slowly and browns less. To ensure the oxidases can work, sulphur must not be added beforehand. The process does not work equally well for all grape varieties – a gain in quality has been documented for Chardonnay, whilst for varieties whose musts are already largely oxidised after pressing, it makes no difference. – SUPERIORE.DE