Amber wine treatment – fermented on skins, shown at the start (left) and end of fermentation (right) Amber wine Since 2016, the AWRI has made a series of wines from single batches of grapes, changing one variable in each fermentation, with the resulting wines being presented to winemakers in workshops around Australia. In this column, Geoff Cowey explores key questions from winemakers on full skin contact in white winemaking – that is, the production of amber wines – one of the treatments included in the 2019 Chardonnay trial.

What is amber wine? at room temperature and are often Is there a standard winemaking considered ‘food wines’. Some producers Amber or ‘orange’ wines are wines made practice for amber wine? use the technique on a portion of fruit from white grapes using techniques Other than fermentation being and then include it in a blend to add traditionally used for red winemaking. performed on skins, not really! Varieties This involves fermentation on skins, complexity or texture. high in phenolics and high in acid can seeds and sometimes stems and can What varieties are used? appear harsh and bitter when made in include extended skin contact post- amber style, with some winemakers fermentation. Amber wine can appear Amber winemaking is considered a choosing to hyperoxidise the must to orange in colour, but also white, regional specialty in places such as Friuli decrease phenolic content. Fermentation yellow, brown or pink, dependent on and Sicily in Italy and parts of Spain, can be conducted in amphorae or in the variety, process undertaken and Slovenia, Georgia and Switzerland, using different types of tanks. Fermentation whether oxidative or reductive handling low aromatic varieties that benefit from is generally performed warm and is employed. Rather than fresh aromatic additional flavours gained through this not temperature controlled. Some or varietal flavours, amber wines tend to technique. The technique is also used winemakers may use natural yeasts, appear more complex and savoury. They with other varieties that contain high others allow film-forming yeast to grow are typically dry, medium or full bodied, on the wine surface after fermentation, amounts of flavonol glycosides locked have noticeable tannin astringency and some allow post fermentation skin- away in their skins, with the aim of and wine texture and can be lower in contact. Amber wines can be made both releasing these flavour precursors to alcohol than other white wine styles. with and without addition of sulfur Grape phenolic under-ripeness and high contribute additional wine flavour. In dioxide to must and to the finished wine. acidity can add perceived bitterness and Australia, varieties used for amber wine Maturation in oak is common to allow enhance astringency. Overripe fruit and include Chardonnay, Pinot Gris and phenolics to soften and integrate with higher pH can make amber wines less Semillon but also aromatic varieties such oak compounds. In the amber treatment astringent but more broad and ‘blousy’. as Riesling, Gewürztraminer, Sauvignon in the 2019 Chardonnay trial, fruit was Amber wines are intended to be drunk Blanc, Muscat and Viognier. hand-harvested and no sulfur dioxide

July 2020 – Issue 678 www.winetitles.com.au Grapegrower & Winemaker 49 was added. The fruit was crushed, feel and texture. Oxygen exposure at the misconstrued as a wine made in the GI destemmed, inoculated (using CY3079) start of fermentation, before fermentative region of Orange or even a fruit wine and fermented on skins and seeds in carbon dioxide accumulates, can result fermented from oranges (Guy 2014). Some an open-top stainless-steel fermenter. in the ‘browning/amber’ colouration producers have thus begun using ‘amber The cap was plunged twice daily then from oxidation of extracted phenolics. wine’ as an alternative description for the pressed. A sulfur dioxide regime typical This can be minimised by adding sulfur winemaking technique. For assistance for standard white winemaking was then dioxide to must but this can also limit with legal requirements regarding implemented during wine storage in later tannin development. As white stainless steel and the wine was bottled grapes contain lower concentrations of labelling these wine styles in Australia, within six months. anthocyanins than red grapes, tannins contact the compliance team at Wine are less likely to be polymerised and Australia on [email protected]. What are the effects on wine retained in the final wine and thus For further information about amber chemistry? amber wines can be more bitter and have winemaking or other technical some astringency but are generally less Fermentation on skins results in winemaking or viticulture questions, increased extraction of varietal grape astringent than red wines. contact the AWRI helpdesk on flavours, occurring mostly in the first A decrease in acidity (or an increase in (08) 8313 6600 or [email protected] third of fermentation, but conversely pH up to 0.2 pH units) occurs due to reduces the amount of fermentation- greater potassium extraction from grape References derived esters, because of inhibitors, skins followed by subsequent potassium Guy, S. 2014. The reasons for raising a red adsorption of precursors onto grape bitartrate precipitation in the wine skins, increased uptake and interaction flag to the use of the term ‘orange’. Wine due to its lower solubility in ethanol. Vitic. J. 29(4): 10. of flavours with oxygen or loss via Lower alcohol levels are typically due evaporation during cap management either to absorption by stems or greater Lukic, I., Lotti, C., Vrhovsek, U. 2017. (Lukic 2017). Additional microbial ethanol evaporation due to warmer Evolution of free and bound volatile aroma diversity would also be expected to effect fermentation temperature and use of compounds and phenols during fermentation fermentation dynamics and flavours. open-top fermenters. of Muscat blanc grape juice with and without Tannin extraction increases steadily skins. Food Chem. 232: 25-35. Can you use the term throughout fermentation, enhanced Townshend, E.R., Harrison, R., Tian, B. 2019. with the increasing ethanol formation, ‘orange wine’? The phenolic composition of orange wine to levels much greater than achieved To consumers, a wine labelled ‘orange — effects of skin contact and sulfur dioxide through pre-fermentation skin contact wine’ could be interpreted as a wine addition on white wine tannin. Wine Vitic. J. techniques, increasing the body, mouth- of orange colour, but also could be 34(2): 25-32.

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