Influence of Fermenttion on Properties of Semillon nd Shirz Wines 235 Influence of Fermenttion Temperture on Composition nd Sensory Properties of Semillon nd Shirz Wines Andrew Reynolds, 1* Mrgret Cliff, 2 Benoit Girrd, 2 nd Thoms G. Kopp 3 Crushed Semillon grpes were pressed fter 24 hr pomce contct nd fermented t one of four tempertures (15, 20, 25, or 30 C) to ssess the effect on the chemicl composition nd sensory properties of the wines. An dditionl tretment (15 C fermenttion without prior pomce contct) ws included to ssess the impct of pomce contct. Shirz grpes were fermented ccording to one of three temperture regimes (15 C; 20 C for 3 dys followed by 30 C; 30 C for 3 dys followed by 20 C), with nd without prefermenttion cold sok. An dditionl tretment involved cold sok, 20 C fermenttion temperture for 3 dys followed by 30 C, plus 3-dy postfermenttion extended mcertion. Incresing fermenttion temperture in Semillon tended to increse titrtble cidity (TA) nd bsorbnce (A 420 ) slightly. The 20 nd 30 C tempertures resulted in the highest ethnol content. Pomce contct reduced wine TA nd incresed ph nd A 420. Within the two 15 C tretments, tsters found pomce contct wines hd less erthy rom nd herbceous flvor. Among the pomce contct tretments, 15 C fermenttions resulted in less yellow color nd herbceous rom, nd fruitier rom thn 30 C fermenttions. Incresing fermenttion temperture, use of cold sok, nd extended mcertion tended to reduce Shirz wine TA nd incresed ph nd nthocynins. Use of cold sok incresed color (15 C only) nd blck currnt flvor, reduced herbceous flvor, but reduced blck currnt rom. Extended mcertion enhnced wine color nd body but incresed herbceous rom. Incresing fermenttion temperture from 15 to 30 C incresed wine color, reduced herbceous flvor, incresed blck currnt flvor, but incresed perceived cidity. These results suggest tht Semillon wines should be produced through the use of prefermenttion pomce contct nd cool fermenttion tempertures, wheres Shirz wines would benefit from higher fermenttion tempertures, use of cold sok, nd extended postfermenttion mcertion. Key words: Arom compounds, fermenttion temperture, red wine, white wine, sensory evlution Wine color, rom, nd flvor depend on both the initil composition of the grpes nd subsequent enologicl processes. White wine sensory qulity hs been clerly shown to benefit from fermenttion tempertures t or below 15 C [6,7,9], lthough some reserchers hve indicted no dvntge of low fermenttion tempertures for Chrdonny [9], French Colombrd [3], Riesling [3], or Horizon [9]. Overll, the bulk of the literture indictes tht fermenttions t low tempertures (~15 C) proceed more slowly thn t 25 to 30 C nd tht, therefore, loss of the primry rom is often minimized [22]. Concentrtions of some high-boiling-point esters, however, increse with incresing fermenttion temperture [19]; mny ethyl esters re especilly odor-ctive nd my contribute to sensory response [17]. Fermenttion temperture cn lso significntly impct red wine style nd qulity [3,4,11,12,13,15,16,23-31]. Elevting 1 Reserch Scientist, Horticulture nd Bsic Studies Progrm; 2 Reserch Scientist, Food Reserch Progrm; 3 Technicin, Food Reserch Progrm, Pcific Agriculture Reserch Centre, Agriculture nd Agri-Food Cnd, Summerlnd, BC, V0H 1Z0, Cnd. Corresponding uthor [Present ddress: Cool Climte Oenology & Viticulture Institute, Brock University, St. Cthrines, ON L2S 3A1, Cnd; emil: reynold@sprtn.c.brocku.c] Acknowledgments: The uthors thnk the following members of the tste pnel: Tony Cottrell, Mrjorie King, Pscl Delquis, Horst Donner, Hilry Grhm, Sndr Stewrt, Lszlo Veto, Doug Wrdle, nd Jim Wild. Thnk you lso to Mrgret Li nd Doug Wrdle for technicl ssistnce, Dinhm Drew for help with Shirz hrvesting, nd Drs. Pscl Delquis nd Joe (G.) Mzz for helpful suggestions nd ides. Mnuscript submitted July 2000; revised Mrch 2001 Copyright 2001 by the Americn Society for Enology nd Viticulture. All rights reserved. fermenttion temperture hs frequently been used in vrieties (such s Pinot noir) for which color extrction is problemtic. Amerine [3] noted tht 10 C fermenttions for Pinot noir wines were inferior to those t 21 C in terms of both color intensity nd flvor nd lter [4] found tht mong rnge of fermenttion tempertures (12, 15.5, 21, nd 27 C), color nd flvor were best in both 21 nd 27 C tretments. More recently, Girrd et l. [16] showed tht 30 C fermenttions produced more intense wine color nd flvor thn 20 C fermenttions nd incresed some nthocynins [15]. Mnipulting fermenttion temperture hs lso been used to optimize the qulity of more hevily pigmented vrieties. For instnce, incresing fermenttion temperture from 12 C to either 20 C or 30 C in Cbernet Suvignon, Grenche, or Pinot noir wines incresed both color nd tnnin extrction [26]. Subsequent work showed liner reltionship between fermenttion temperture nd wine qulity for these three cultivrs nd Vldepeñs [28,29]. Most red wine fermenttions in Cliforni re crried out between 20 nd 35 C [8]. Prefermenttion pomce contct ( cold sok ) nd extending the mcertion period pst the end of fermenttion re techniques trditionlly used in Frnce to improve color in red wine. Their specific effects on wine composition nd sensory qulity hve not been well reserched. Hetherbell et l. [18] demonstrted tht use of cold sok incresed phenols nd nthocynins in Pinot noir, but tended to reduce berry rom nd incresed tobcco rom nd bitterness. Recently, McMhon et l. [20] 235
236 Reynolds et l. demonstrted increses in Cbernet Suvignon glycosides s result of cold-sok tretments. Semillon nd Shirz re ntive to the Bordeux nd Rhone regions in southern Frnce but re being plnted extensively in mny cooler climte viticulturl regions. Growers in the Okngn Vlley of British Columbi (BC) nd the Nigr Peninsul in Ontrio re incresing the creges of these vrieties. Both Semillon nd Shirz mture lte in the seson nd frequently contin intense herbceous flvors [10,32]. Producing Semillon with more intense fruit nd florl roms nd flvors nd Shirz with greter color nd intensity of fruit flvors hve become high priorities mong BC winemkers. The objective of this study ws to evlute fermenttion tretments involving vrious tempertures, use of prefermenttion pomce contct, nd extended mcertion upon stndrd chemicl composition nd sensory properties of Semillon nd Shirz wines. It ws our hypothesis tht combining high-temperture fermenttion (~30 C) with prefermenttion pomce contct in Semillon might enhnce florl nd fruity chrcter through extrction of monoterpenes [35] nd other odor-ctive constituents from the skins, while leding to voltiliztion of compounds such s methoxypyrzines, which cuse excess herbceousness. Furthermore, we hypothesized tht combining prefermenttion cold sok nd postfermenttion mcertion with incresing fermenttion temperture would produce Shirz wines with enhnced vrietl intensity nd color compred to conventionl fermenttions. Mterils nd Methods Winemking. Semillon: About 450 kg of Semillon grpes from the Kirschmn Vineyrd, Summerlnd, BC were hrvested t 18.4 Brix, 11.0 g/l titrtble cidity, nd 3.09 ph on 8 November 1993 nd held t 2 C. Grpes were crushed nd destemmed on 10 November using Groll-type crusherdestemmer into 20-L food-grde plstic pils. Twenty continers of crushed grpes were obtined, four of which were immeditely pressed using hydrulic rck-nd-cloth press. Must ws sulfited to 50 mg/l nd held t 2 C in three 20-L glss crboys. The remining 16 continers were given ~24 hr pomce contct t 2 C, pressed, nd 50 mg/l SO 2 ws dded to the must. Pomce contct must (200 L) ws divided eqully into twelve 20-L crboys. Three crboys were ech trnsferred to djcent fermenttion rooms held t 15, 20, 25, nd 30 C. The three crboys of nonpomce contct must were lso trnsferred to the 15 C room. Musts were then llowed to settle for 24 hr, rcked, nd inoculted with Scchromyces bynus strin EC 1118 (Lllemnd Corp., Montrel). Overll, there were four fermenttion tempertures with pomce contct (hereinfter designted 15P, 20P, 25P, nd 30P), nd comprison of use (15P) or nonuse of pomce contct followed by 15 C fermenttion (15CP), with three fermenttion replictes of ech tretment. A mlolctic fermenttion ws not ttempted due to the low wine ph (bout 3.15). Wines were rcked fter completion of fermenttion, cold stbilized t -2 C, filtered using pd filter (0.45 µm) nd crtridge filter (0.2 µm), bottled (750 ml flint Bordeux with 4.4 cm corks), nd stored t 11 C until tsting. Wines received n dditionl 50 mg/l SO 2 t the end of fermenttion nd t bottling. Shirz: Approximtely 500 kg of Shirz grpes were hrvested t 18.9 Brix from the Nichol Vineyrd Frm Winery on 17 November 1993 nd were held t 2 C until crushing on the following dy. Grpes were crushed nd destemmed in Grolltype crusher-destemmer into 20-L food-grde plstic pils. A totl of thirty-five 20-L continers of crushed grpes were obtined, 20 of which were sulfited to 50 mg/l nd held t 2 C (cold sok) for 10 dys. The remining 15 continers were held overnight (~24 hr) t 2 C nd inoculted the following dy with S. cerevisie strin Wdenswil 27 (Lllemnd Corp., Montrel). Agin, 50 mg/l SO 2 ws dded t crush. These continers were divided into three fermenttion temperture tretments of five replictes ech. The tretments were crried out in djcent fermenttion rooms: 15 C constnt; 20 C for 3 dys followed by 30 C therefter; nd 30 C for 3 dys followed by 20 C therefter. For conciseness, these tretments will be hereinfter referred to s 15C, 20C, nd 30C, respectively. Fifteen of the 20 continers subjected to the cold sok were treted in the sme mnner 10 dys lter. These tretments will be hereinfter referred to s 15CS, 20CS, nd 30CS, respectively. The remining five continers were given tretment equivlent to 20CS, plus 3 dys of postfermenttion extended mcertion (20EM). Fermenttions were punched down three times dily until completion, fter which wines were pressed in hydrulic rcknd-cloth press, trnsferred into glss crboys, nd replced in their respective fermenttion rooms. Wines were then rcked fter 24 hr, cold stbilized t -2 C, nd the five replictes were blended into three tsting replictes by combining replictes 1 nd 2, nd 4 nd 5 together. A mlolctic fermenttion ws not ttempted due to the low wine ph (bout 3.00). Ech tsting replicte ws then given 14 dys of tretment in new mediumtosted 20-L Americn ok brrel. Ech received n dditionl 50 mg/l SO 2 t the end of fermenttion nd prior to bottling. The wines were then filtered using plte nd frme filter (0.45 µm) nd crtridge filter (0.2 µm), bottled (750 ml green Bordeux with 4.4 cm corks), nd stored t 11 C until tsting. Must nd wine composition. Must nd wine smples (200 ml) were retined from ll tretment replictes prior to blending nd were nlyzed for soluble solids ( Brix; must only), titrtble cidity (TA), nd ph by stndrd methods [5]. Totl nthocynins in the Shirz musts nd wines were determined by the ph shift method of Metivier et l. [21]. Absorbnce (A 420 ) ws mesured on the Semillon wines using Vrin DMS-100 spectrophotometer (Vrin Cnd Inc., Mississug, ON). Soluble solids ( Brix) were mesured dily on the tretment replictes to monitor fermenttion rtes using temperture-compensted Abbé refrctometer (AO Scientific Instruments, Bufflo, NY); TA ws mesured on Brinkmnn utotitrtor (Metrohm, Herisu, Switzerlnd); nd ph ws mesured on Fisher 825MP ph meter (Fisher Scientific, Vncouver, BC). Ethnol concentrtion ws determined using Hewlett-Pckrd 5700 gs chromtogrph (GC; Hewlett-Pckrd, Avondle, PA) equipped with Porpk Q-100 column (3.2 mm x 2 m). Other conditions of opertion included: N 2 crrier gs flow rte 20 ml/ min; oven temperture 175 C; injector temperture 200 C; nd detector temperture 200 C. Wine smples (2 ml) were pipetted
Influence of Fermenttion on Properties of Semillon nd Shirz Wines 237 into 100 ml volumetric flsks nd mde up to volume with 0.2% isopropnol s the internl stndrd. Injection volume ws 1 µl. Sensory evlution. Wines were bench tested during two sessions in Jnury 1997 fter 30 months bottle storge, using four wine experts. Tenttive sensory ttributes were selected by roundtble discussion. It ws consensully greed tht tretment differences were not of sufficient mgnitude to wrrnt detiled descriptive nlysis nd tht the high cidities of the Shirz wines could limit the bility of some judges to differentite smll retronsl rom ( flvor ) differences. Therefore, the two-lterntive forced-choice method (pir-comprison; PC) ws chosen to evlute the wines. Obvious sensory differences were not pprent mong the three tsting replictes; therefore, only two of three replictes were chosen for sensory evlution. Rther thn evlute ll possible combintions of the Semillon tretments, 15P ws selected s the control to which ll other tretments were compred. Similrly, the most relevnt 8 of 21 possible pirs were compred for the Shirz wines: the use or nonuse of cold sok t ech temperture; 15C with 20C nd 30C; 20CS versus 20EC; nd 30CS versus 15CS nd 20CS. Fifteen (Semillon) nd 14 (Shirz) tsters evluted the wines, in duplicte, in two consecutive dys. All were employees of Agriculture nd Agri-Food Cnd nd hd extensive previous experience with wine sensory nlysis. Judges were fmilirized with the protocol nd selection/definition of the sensory descriptors during trining session. Judges conducted their evlutions t series of tsting tbles (one per sensory descriptor), which were rrnged to minimize potentil sensory bis. Ech tsting tble consisted of series of four PC evlutions for the Semillon wines nd eight PC for the Shirz wines. Smples were blnced for order of presenttion. Judges evluted ech pir of smples nd circled the number corresponding to the smple with the gretest intensity (ttribute specified). This ws repeted for ech ttribute. PC evlutions were rndomized mong tsters. Ech ttribute ws ssigned different set of rndom numbers to void ny possible numericl bis. Judges first evluted rom ttributes of the smples in 250 ml blck wine glsses lbeled with three-digit rndom number. Other smples of the sme wines coded with different threedigit rndom numbers were then evluted by the sme judges for the flvor ttributes in 250 ml cler wine glsses. Intensity of yellow color in Semillon nd red color in Shirz were evluted lst under nturl light ginst white bckground. Sttisticl nlysis. Anlysis of vrince ws crried out on chemicl nlysis dt (GLM procedure, SAS, 1993 [SAS Institute, Cry, NC]). Liner nd qudrtic trends were scertined through use of single degree of freedom contrsts. Anlysis of the sensory dt ws conducted using tbles prepred by Roessler et l. [33]. Results nd Discussion Must nd wine nlysis. Semillon: Must composition ws not significntly different between pomce contct tretments (dt not shown). Wine TA nd bsorbnce were highest t fermenttion tempertures 25 C, nd ph displyed similr trend (Tble 1). There ws lso n effect of fermenttion temperture on ethnol concentrtion, but trend ws not pprent (Tble 1). In generl, the differences were reltively smll. Use of pomce contct reduced wine TA nd incresed ph nd bsorbnce. Severl studies hve reported incresed TA with incresing fermenttion tempertures [3,4,26,27,28,30] nd inferred tht it my be prtilly due to production of significnt mounts of cetic nd succinic cids [27,30]. Fleet et l. [13] showed tht non-scchromyces yests cpble of metbolizing mlic cid were most ctive t lower tempertures. The increse in TA with fermenttion temperture in this study my be explined by these phenomen. Cottrell nd McLelln [9] showed decrese in TA in wines of seven white vrieties s fermenttion temperture incresed from 8 to 25.5 C, but did not offer n explntion. The slight increse in bsorbnce resulting from pomce contct nd incresed fermenttion temperture my hve been the result of phenolic oxidtion. Phenolic compounds hve been shown to increse in concentrtion in white wines with incresing fermenttion temperture [9,30]. TA nd ph differences between prefermenttion tretments my lso hve been due to some precipittion of trtric cid during pomce contct. Shirz: In generl the grpes used for this tril were not fully mture, nd, consequently, wine TA ws very high nd ph nd ethnol were quite low (Tble 2). Wines were nonetheless intensely colored. Differences were not found between tretments in terms of must composition (dt not shown), lthough slight reduction in must TA ws expected for the cold sok tretments due to trtrte precipittion. Incresing fermenttion temperture reduced TA nd ethnol nd tended to increse wine nthocynins (Tble 2). Use of prefermenttion cold sok reduced wine TA but incresed nthocynins nd ethnol (Tble 2). At 20 C fermenttion, the use of extended mcertion in ddition to cold sok produced wines with lowest TA nd highest ph, nthocynins, nd ethnol. Interctions between the fermenttion tempertures nd the cold-sok tretments suggested tht cold sok incresed wine ph t the higher fermenttion tempertures only, but no benefit of cold sok ws observed in terms of Tble 1 Chemicl composition of 1993 Semillon wines fermented t four different tempertures. Titrtble Absorbnce Ethnol Fctor cidity (g/l) ph (420 nm) (%) Fermenttion temp ( C) 15 9.7 3.17 0.092 11.7 20 9.7 3.15 0.085 12.4 25 9.8 3.15 0.102 11.6 30 10.4 3.16 0.101 12.7 Std. error of the men 0.11 0.04 0.017 0.13 Significnce *** * *** *** Prefermenttion tretment t 15 C Crush nd press 10.0 3.02 0.081 11.4 24 hr pomce contct 9.7 3.17 0.092 11.7 Std. error of the men 0.14 0.03 0.022 0.18 Significnce * *** ** ns *, **, ***, ns: significnt t p 0.05, 0.01, 0.001, or not significnt, respectively.
238 Reynolds et l. Tble 2 Effects of fermenttion temperture, prefermenttion cold sok, nd postfermenttion extended mcertion on composition of 1993 Shirz wines. Titrtble Totl Ethnol cidity nthocynins (%) Fctor (g/l) ph (mg/l) Min effects: Initil fermenttion ( C) 15 11.4 2.94 348.4 9.23 20 11.2 2.97 393.6 7.70 30 10.8 2.95 392.1 7.93 Stndrd error of the men 0.16 0.04 1.54 0.17 Significnce ** ** *** *** Min effects: Prefermenttion tretment Crush only (C) 11.4 2.94 360.4 8.03 10 d cold sok (CS) 10.8 2.96 395.7 8.53 Stndrd error of the men 0.16 0.04 1.56 0.25 Significnce *** ns *** ** Pre- nd postfermenttion tretments (20 C) Crush only (C) 11.6 b 2.96b 370.4b 7.50c 10 d cold sok (CS) 10.8b 2.99b 416.8 7.90b 3 d extended mcertion 10.3b 3.03 444.2 8.30 Significnce * * ** ** Interctions (Fermenttion temp x CS) 15C 11.6 2.94 313.7 8.90 15CS 11.2 2.93 383.2 9.55 20C 11.6 2.96 370.4 7.50 20CS 10.8 2.99 416.8 7.90 30C 11.1 2.92 387.0 7.70 30CS 10.5 2.98 387.1 8.15 Stndrd error of the men 0.11 0.02 0.99 0.12 Significnce ns ** ** ns *, **, ***, ns: significnt t p 0.05, 0.01, 0.001, or not significnt, respectively. b Mens followed by different letters re significnt t p 0.05, Duncn s multiple rnge test. Tble 3 Number of responses from pir comprison evlutions (n=15) of Semillon wines fermented under different tempertures, for eight sensory ttributes. Color nd rom Yellow color Fruity Herbceous Erthy Pir Responses Pir Responses Pir Responses Pir Responses 15C vs 15P b 9 ns c 15P vs 15C 8 ns 15P vs 15C 9 ns 15P > 15C 13*** 20P vs 15P 8 ns 20P vs 15P 9 ns 20P vs 15P 9 ns 20P vs 15P 8 ns 15P > 25P 12** 15P vs 25P 9 ns 25P vs 15P 8 ns 25P vs 15P 8 ns 30P > 15P 15**** 15P > 30P 11* 30P > 15P 11* 15P vs 30P 8 ns incresed wine nthocynins t the highest fermenttion temperture (Tble 2). The reduced TA with incresed fermenttion temperture my be result of n enhncement of the yest s bility to metbolize mlic cid. Higher ethnol concentrtion t lower fermenttion temperture is consistent with previous reserch [9,23,24,25]. At tempertures between 15 nd 20 C, yests hve been shown to be most ethnol tolernt [23,24,25,34], lthough Ferreir [12] found tht both yest cell growth nd ethnol production were optiml t 30 C. Increses in nthocynins due to incresed fermenttion temperture hve lso been previously documented [15,16,26,27,28]. Mny studies hve confirmed cler reltionship between fermenttion temperture nd degree of color extrction in the resultnt wines [26,27,28]. Prefermenttion tretments in the presence of SO 2 lso induce preferentil queous diffusion of nthocynins [18]. Fermenttion rtes. Fermenttion rtes bsed on Brix vried ccording to fermenttion temperture (dt not shown) nd support previous work [23,25,26,27,28]. Fermenttion progressed fster s vinifiction temperture incresed, consistent with industry experience nd prior literture [16,23,25,26,27,28]. For Semillon, fermenttions conducted t 20 to 30 C were complete in 5 dys, wheres 15 C fermenttions took 7 dys. For Shirz, durtions of fermenttions were 10, 8, nd 7 dys for the 15, 20, nd 30 C fermenttions, respectively. Sensory nlysis. Semillon: Differences were not found between the 15P tretment nd the other wines in terms of fruity flvor, perceived cidity, nd body/finish. Differences were found for yellow color, ll rom descriptors, nd herbceous flvor (Tble 3). The unnimous choice of 30P s hving higher yellow color is consistent with the bsorbnce dt (Tble 1); however, tsters found tht 25P wines hd less yellow color. Tsters lso found tht the 30P wines hd less fruity nd more herbceous rom nd tht the 15CP tretment reduced Flvor Fruity Herbceous Acidity Body/finish Pir Responses Pir Responses Pir Responses Pir Responses 15P vs 15C 8 ns 15C > 15P 11* 15C vs 15P 8 ns 15P vs 15C 8 ns 20P vs 15P 9 ns 15P vs 20P 8 ns 15P vs 20P 8 ns 15P vs 20P 9 ns 15P vs 25P 8 ns 25P vs 15P 10 ns 25P vs 15P 10 ns 15P vs 25P 8 ns 30P vs 15P 8 ns 30P vs 15P 9 ns 15P vs 30P 10 ns 15P vs 30P 8 ns The number of sensory responses refers to the number of pnelists identifying the first wine in the pir (column 1) s hving the greter perceived intensity. b 15, 20, 25, nd 30 refer to fermenttion temp ( C); C nd P: crush/press nd pomce contct, respectively. c *, **, ***, ****, ns: significnt t p 0.10, 0.05, 0.01, 0.001, or not significnt, respectively; two-tiled test, n=15. erthy rom nd herbceous flvor (Tble 3). Vegetl nd herbceous rom nd flvor of Semillon wines re often ttributed to methoxypyrzine compounds [2] nd thiol compounds [36,37], while fruity notes re derived minly from monoterpene nd norisoprenoid glycosides [35,38] s well s other thiol derivtives [36]. Although it ws hypothesized tht incresing the fermenttion temperture would increse the loss of vegetl rom compounds through voltiliztion, sensory results indicted tht fruity rom ws
Influence of Fermenttion on Properties of Semillon nd Shirz Wines 239 reduced while herbceousness ws enhnced. This suggests tht incresed losses in free monoterpenes nd norisoprenoids my hve occurred through voltiliztion s fermenttion temperture ws incresed nd/or tht the concomitnt losses in methoxypyrzines nd thiol compounds were of insufficient mgnitude to evoke positive sensory response. Although work of this nture hs not previously been pursued with Semillon, must heting ws shown to enhnce florl nd fruity chrcteristics of Austrlin Semillon wines [14]. Shirz: Use of cold sok incresed red color, decresed blck currnt rom (15 C nd 30 C), incresed blck currnt flvor (15 C nd 20 C) nd herbceous rom (30 C), but reduced herbceous flvor (15 C) nd perceived cidity (30 C)(Tble 4). Incresed fermenttion temperture lso incresed red color nd blck currnt flvor (30C versus 15C), nd reduced herbceous flvor (15C versus 30C; 15CS versus 30CS) (Tble 4). Perceived cidity ws incresed with incresed fermenttion temperture for two pirs (30C versus 15C; 20C versus 15C), but the 30CS wines hd perceptibly less cidity thn the 15CS wines (Tble 4). Extended mcertion incresed red color, herbceous rom, nd body/finish (Tble 4). There were no tretment effects on erthy rom. These results re consistent with those of Girrd et l. [16], who found increses in red color nd currnt rom nd flvor of Pinot noir wines s fermenttion temperture incresed from 20 to 30 C. Unlike Hetherbell et l. [18], cold sok enhnced mny sensory chrcteristics such s color nd blck currnt rom nd flvor. Abbott et l. [1] ssocited higher intensities of nonberry sensory ttributes (for exmple, stlky, erthy, tobcco) with highest qulity Austrlin Shirz. However, the enhncement of blck currnt notes in the wines in this study ws viewed s generlly positive response. Conclusions Semillon wines fermented under different tempertures differed slightly in their chemicl composition. However, chnges in sensory chrcteristics such s incresed color nd herbceous rom nd reduced fruity rom resulted from increses in fermenttion temperture. Prefermenttion pomce contct incresed erthy rom but decresed herbceous flvor. Although specultive, it is possible tht the monoterpenes responsible for the fruity chrcteristics in Semillon [32,35] were lost through voltiliztion t high fermenttion tempertures, wheres the methoxypyrzines [2] nd thiols [36,37] ssocited with herbceous, boxwood, nd broom tree roms were not. Approprite rom descriptors for these thiol compounds were not found in the wines under investigtion, however. Fermenttion tempertures of 15 C with the use of prefermenttion pomce contct re thus recommended for this vriety. Shirz wines displyed increses in nthocynins nd ph, but decreses in TA nd ethnol reltive to incresing fermenttion temperture, use of prefermenttion cold sok, nd use of postfermenttion extended mcertion. Incresing fermenttion temperture nd use of either cold sok nd/or extended mcertion incresed red wine color nd blck currnt flvor nd in some cses reduced herbceous flvor nd perceived cidity. The Tble 4 Sensory responses from pir comprison evlutions (n=14) of Shirz wines fermented under different tempertures, prefermenttion cold sok, nd postfermenttion extended mcertion, for eight sensory ttributes. Color nd rom Red color Blck currnt Herbceous Erthy Pir Responses Pir Responses Pir Responses Pir Responses 15CS > 15C b 10* c 15C > 15CS 11** 15C vs 15CS 8 ns 15CS vs 15C 9 ns 20C vs 20CS 9 ns 20C vs 20CS 8 ns 20C vs 20CS 7 ns 20CS vs 20C 8 ns 30C > 15C 11** 15C vs 30C 8 ns 30C vs 15C 9 ns 15C vs 30C 8 ns 20C vs 15C 9 ns 15C vs 20C 7 ns 20C vs 15C 8 ns 20C vs 15C 9 ns 15CS vs 30CS 8 ns 15CS vs 30CS 8 ns 30CS vs 15CS 8 ns 15CS vs 30CS 9 ns 20EM > 20CS 13*** 20EM vs 20CS 9 ns 20EM > 20CS 11** 20EM vs 20CS 9 ns 30CS vs 20CS 8 ns 30CS vs 20CS 9 ns 20CS vs 30CS 8 ns 30CS vs 20CS 8 ns 30C > 30CS 11** 30C > 30CS 13*** 30CS > 30C 10* 30C vs 30CS 8 ns Flvor Blck currnt Herbceous Acidity Body/finish Pir Responses Pir Responses Pir Responses Pir Responses 15CS > 15C 10* 15C > 15CS 10* 15C vs 15CS 9 ns 15C vs 15CS 7 ns 20CS > 20C 11** 20C vs 20CS 8 ns 20C vs 20CS 9 ns 20C vs 20CS 8 ns 30C > 15C 10* 15C > 30C 10* 30C > 15C 11** 15C vs 30C 8 ns 15C vs 20C 7 ns 15C vs 20C 7 ns 20C > 15C 10* 15C vs 20C 7 ns 30CS vs 15CS 9 ns 15CS > 30CS 12*** 15CS > 30CS 11** 15CS vs 30CS 8 ns 20CS vs 20EM 8 ns 20EM vs 20CS 9 ns 20CS vs 20EM 8 ns 20EM > 20CS 13*** 20CS vs 30CS 8 ns 20CS vs 30CS 8 ns 20CS vs 30CS 8 ns 30CS vs 20CS 9 ns 30C vs 30CS 9 ns 30CS vs 30C 9 ns 30C > 30CS 10* 30CS vs 30C 8 ns The number of pnelists identifying the first wine in the pir s hving greter intensity. b 15, 20, nd 30 refer to fermenttion temp ( C); C, CP, nd EM: crush, cold sok, nd extended mcertion, respectively. c *, **, ***, ns: significnt t p 0.10, 0.05, 0.01, or not significnt, respectively; two-tiled test, n=14.
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