Alternative management of lees in the vinification of Sangiovese grapes Giovanna Fiaa a University of Florence, Dipartimento di Gestione dei Sistemi Agrari, Alimetari e Forestali, via Donizetti, 6, 50144 Florence, Italy. Keywords: lees; polysaccharides; polyphenols; proteins; astringency; wine 1. INTRODUCTION This study arises from the need to recover by-products of winemaking that are still able to provide active wine compounds such as polyphenols, aromas and polysaccharides. The role of lees in the traditional aging of wine has been reported [1]. There is no doubt that leeswine contact contributes to the quality of wine but the key compounds and interactions responsible for wine improvement are still not completely clear. In any case, the positive effects of aging on lees are reached after a long period of contact and periodic “bâtonnage” as described by several authors [1-2]. This work presents an alternative approach to lees management on an industrial scale as performed by the fully automatic ExtraVelvet 1.0 system with the aim of recovering by-products of winemaking with very short processing times. 2. MATERIALS AND METHODS The tests were carried out on an industrial scale using the lees of Sangiovese grapes, vintages 2012 (Chianti area) and 2013 (Montalcino, Siena). The grapes were harvested in excellent health. After completion of alcoholic and malolactic fermentations, the wines were kept in a tank for sedimentation depending on the winery protocol and then decanted. The lees were collected in a 150 hL tank and added with 70 mg L-1 of SO2. After a pump-over of 30 min, the lees were used to fill an ExtraVelvet 1.0 system. The ExtraVelvet 1.0 is a stainless steel macerator with 25 hL capacity, equipped with four scrolls to stir up the lees, an automatic temperature control, and micro-oxygenation system (Figure 1). For tests A and B (vintage 2012), lees (1.2 and 1.1 g L-1, respectively) were maintained at 22 °C and stirred every two days for 30 min. Samples were taken every 15 days until the end of treatment (1 and 2 months for test A and B respectively). For test C (vintage 2013), lees (1.4 g L-1) were maintained at 22 °C with micro-oxygenation (3 mL/L/month of O2) and stirred every 8 h for 10 min for seven days. Then the lees were kept still at 20 °C, with microoxygenation (3 mg/L/month of O2). Samples were taken at 0, 3, 7 days of treatment and after 30 days. Reference samples CA, CB and CC were taken from the tanks where lees were maintained still at 20°C. Tests were performed with lees maintained in the tank for about one month (A and C) and two months (B) after decantation. The following parameters of wine obtained from lees were determined: colour intensity (I) and tonality (T) [3]; total polyphenol (TPI280) [4]; total flavonoids, (TF) total anthocyans (TA) total non-anthocyanic flavonoids [5]; monomeric (Mon %), polymeric (Pol %) and copigmented (Copig %) anthocyanins, cofactors (C) [6]; astringency mucin index (AMI) [7]; gelatine index (G) [8]; total polysaccharides (TP) [9]; total proteins (TPr) [10] and -amino nitrogen (N) [11]. Figure 1. The ExtraVelvet 1.0 system. 3. RESULTS AND DISCUSSION Per motivi di riservatezza, i risultati e le conclusioni dello studio possono venire fornite solamente su richiesta specifica e non in forma anonima. Invitiamo pertanto ad inviarci i seguenti dati per poter ricevere la parte mancante. I dati da inviare all’indirizzo [email protected] sono Nome, Cognome, Azienda ed Indirizzo email.