orange wine

Skin-contact maceration is a winemaking process in which the skins and seeds of white and gray grape varieties remain in contact with the juice before and after fermentation. As phenolic extraction proceeds, the perception of astringency and bitterness is described as potentially changing, and white wines made with prolonged skin contact are called 「オレンジワイン」 (in translation: "orange wine") or 「アンバーワイン」 (in translation: "amber wine"). A 2015 study compared wines made from Riesling and Gewürztraminer (2009 and 2010 vintages) with different skin-contact durations using 3 methods: descriptive analysis (DA), time-intensity (TI), and temporal dominance of sensations (TDS). Wines fermented fully on the skins were significantly more bitter than any other wine by DA and TI. Yet in TDS, the dominant sensation in the same wines was the mouthfeel of astringency, not bitterness. Varietal differences also appeared: Riesling differed significantly only in bitterness and color, whereas Gewürztraminer differed in bitterness, sweetness, sourness, astringency, several aroma attributes, and color. This example shows that conclusions about 「何が優勢な感覚か」 (in translation: "which sensation is dominant") can diverge by measurement method.

A conference poster published in 2026 used the Armenian variety Mskhali and Rkatsiteli, originally from Georgia and also widely cultivated in Armenia, to evaluate naturally fermented, low-intervention skin-contact wines (orange wines) descriptively with 2 panels, one in Armenia and one in Italy. Shared descriptors included dried fruit, cooked apple, apricot, walnut, honey, green (vegetal) notes, and orange blossom, as well as 「中程度の苦味」 (in translation: "moderate bitterness") and 「紅茶様の渋味」 (in translation: "black-tea-like astringency"). Chemical analysis found ranges of 10.7–11.9% alcohol, 4.20–5.83 g/L titratable acidity, and pH 3.52–4.07, and reported higher phenolic content in Rkatsiteli. The blend of both varieties, "Yerevak Orange Natural", was described as having a more structured, black-tea-like tannic character than Mskhali alone. The source does not state whether the poster was peer reviewed; given its poster format and small scale, these findings are treated as provisional.

In another study using South African Chenin Blanc, wines were made from the same source grapes under 3 conditions: a control without skin contact, skin contact only before fermentation (ScBF), and full fermentation on the skins (FoS), then assessed by a descriptive-analysis panel. Mean bitterness intensity was 30.36 for the control, 31.16 for ScBF (not significantly different from the control), and 46.70 for FoS (significantly higher than the control, p<0.001). The panel also rated astringency and sourness higher in FoS than in the control for the same wines. Thus brief skin contact only before fermentation showed no significant change in bitterness, whereas prolonged contact throughout fermentation significantly increased it.