Oak chips and wine. A clear technology
Cichelli,-A; Liberatore,-L; Cantarini,-L; Piracci,-F; Procida,-G; Piracci,-A
Industrie-delle-Bevande. 2004; 33(194): 533-539 ; 9 ref.
Dipartimento Sci., Univ. Chieti, Pescara, Italy
Studies on use of oak chips in winemaking are reported. Aspects investigated include: ageing of wines in the presence of oak chips; extraction of aroma compounds into wines; effects on colour properties of wines; effects on anthocyanins composition; effects on sensory properties; and effects of oak chip type and degree of toasting on the impact of oak chips on wine properties.
Accelerated aging of wine vinegars with oak chips: evaluation of wood flavour compounds.
Morales,-M-L; Benitez,-B; Troncoso,-A-M
Food-Chemistry. 2004; 88(2): 305-315 ; 38 ref.
Area de Nutr. y Bromatologia, Fac. de Farmacia, Univ. de Sevilla, E-41012 Seville, Spain.
Tel. +34-954-556-759/761. Fax +34-954-233765.
E-mail: amtroncoso@us.es
Using 2% w/v oak chips with various pretreatments (boiled and toasted at 180°C, or just toasted at 180°C), assays were conducted of accelerated ageing in wine vinegars. Volatile compounds from wood in aged vinegars were determined using solid phase extraction followed by GC, and oak chips were tested as an alternative to oak barrels in the maturation of wine vinegars. On comparing accelerated ageing for 15 days with traditional ageing in oak barrels for 180 days, results showed that the biggest difference was apparent in the rate of vanillin extraction. Concn. of vanillin was increased 20x by oak-chip ageing. Use of oak chips that were just toasted increased levels of oak-lactone isomers. It is concluded that the use of oak barrels may be substituted by toasted oak chips, which, after just 15 days, may yield wine vinegars with characteristics unique to oak wood.
Barrel renewal systems - a user's perspective.
Stutz,-T; Lin,-S; Herdman,-I
American-Journal-of-Enology-and-Viticulture. 1999; 50(4): 541-543
Mirassou Vineyards, San Jose, CA, USA.
E-mail: stutz@mirassou.com
Experience with alternatives to oak barrels for fermentation and ageing of wines is discussed with special reference to oak stave inserts for barrels or tanks. Effects of these systems on sensory properties of red and white wines are discussed, together with stave size, end grain exposure, service life of the staves, etc.
Using dimethyldicarbonate to minimize sulfur dioxide for prevention of fermentation from excessive yeast contamination in juice and semi-sweet wine.
Threlfall,-R-T; Morris,-J-R
Journal-of-Food-Science. 2002; 67(7): 2758-2762 ; 32 ref.
Inst. of Food Sci. & Eng., Univ. of Arkansas, Fayetteville, AR 72704, USA.
E-mail: ju.morris@uark.edu
Antimicrobial activity of SO2 (0, 10, 25 and 50 mg/l) and/or dimethyldicarbonate (DMDC; 0, 50, 100 and 200 mg/l) at different pH levels (3.0, 3.2, 3.4 and 3.6) in grape juice and semi-sweet wine was investigated, by monitoring yeast growth and visible fermentation at 20°C after excessive contamination (500-700 cfu/ml) with Saccharomyces bayanus. The lowest levels of preservatives that prevented yeast growth and visible fermentation at all pH levels were 50 mg/l SO2 + 100 mg/l DMDC in juice, and 10 mg/l SO2 + 50 mg/l DMDC in wine . Results indicate that DMDC and minimal SO2 levels prevented fermentation in juice and semi-sweet wine when contaminated with 500-700 cfu/ml of S. bayanus.
Examination of the sulfur dioxide-ascorbic acid anti-oxidant system in a model white wine matrix.
Bradshaw,-M-P; Scollary,-G-R; Prenzler,-P-D
Journal-of-the-Science-of-Food-and-Agriculture. 2004; 84(4): 318-324 ; 29 ref.Nat.
Wine & Grape Industry Cent., Charles Sturt Univ., Locked Bag 588, Wagga Wagga,NSW 2678, Australia.
E-mail: gscollary@csu.edu.au
Journal-of-Agricultural-and-Food-Chemistry. 2004; 52(5): 1181-1189 ; 43 ref.
Ascorbic acid and SO2 can be used together as an antioxidant system in white wines; however, there is evidence that ascorbic acid can act as a prooxidant leading to elevated levels of oxidative spoilage. In this study, a model white wine matrix containing (+)-catechin was used to study the ascorbic acid-SO2 antioxidant system. A model wine base was prepared that contained: (+)-catechin (100 mg/l; 3.45 x 10-3M); (+)-catechin and ascorbic acid (200 mg/l; 1.14 x 10-3M); (+)-catechin and SO2 (50 mg/l; 7.81 x 10-4M); or (+)-catechin, ascorbic acid and SO2 (0.8:1.0, SO2:ascorbic acid). Absorbance was measured at 440 nm. The browning curve for the reaction system containing (+)-catechin and ascorbic acid showed a lag period of 2 days before an increase in absorbance was seen. With SO2 present the lag period was extended to 4 days, but after this browning occurred at a sufficiently rapid rate to achieve the same absorbance after 14 days as in the absence of SO2. The (+)-catechin and SO2 system totally inhibited browning. When the ratio of SO2 to ascorbic acid was increased to 3:1, oxidation of (+)-catechin was inhibited even in the presence of ascorbic acid; however, in the (+)-catechin/ascorbic acid/SO2 system, 73% of the SO2 was consumed over the 14 day reaction period, in contrast to 26% in the (+)-catechin/SO2 system, indicating the rapid consumption of SO2 as ascorbic acid is oxidised. It is suggested that if ascorbic acid is to be used in the finishing of wine, the concn. of SO2 used should be sufficient to ensure that residual free SO2 is available over the lifetime of the wine.
Protection of white winemaking grapes against oxidation by use of ascorbic acid. Experimental results.
Charrier,-F; Cottereau,-P
Revue-Francaise-d'Oenologie. 2003; (201): 12-15
Unite de Nantes, ITV France, Chateau de la Fremoire, 44120 Vertau, France
Comparative trials were conducted on use of SO2 alone (at 5 g/100 kg) or SO2 (5 g/100 kg) in combination with ascorbic acid (10 g/100 kg) for control of oxidation of white winemaking grapes or musts before fermentation. Trials were conducted on batches of Sauvignon Blanc, Muscat, Riesling, Melon Blanc and Grenache Blanc grapes. Results showed that the combined SO2/ascorbic acid treatment decreased browning of the grapes and musts, but adversely affected colour stability of the resulting wines. The SO2/ascorbic acid treatment gave higher total SO2 concn. than SO2 alone. However, the former had higher bound SO2 concn. It is concluded that use of ascorbic acid does not permit reduction of SO2 use level in wines. Other analytical parameters of the wines differed little between the 2 treatments. Use of SO2 increased aroma intensity (especially citrus fruit and tropical fruit notes) of wines made from aromatic cultivars such as Sauvignon Blanc and Riesling.
The complexities of using ascorbic acid as an antioxidant.
Bradshaw,-M-P; Scollary,-G-R; Prenzler,-P-D
Australian-&-New-Zealand-Grapegrower-&-Winemaker. 2003; (473): 62-65
Nat. Wine & Grape Ind. Cent., Charles Sturt Univ., Locked Bag 588, Wagga Wagga, NSW 2678, Australia.
Tel. +61 2 6933 4030. Fax +61 2 6933 4068.
E-mail: gscollary@csu.edu.au
Use of ascorbic acid as an antioxidant in wines is discussed, with reference to studies on behaviour of ascorbic acid and its effect on browning of catechin under white wine conditions. Trials were conducted with catechin and ascorbic acid concn. considerably greater than those occurring in white wines. Results showed that: ascorbic acid is a highly effective antioxidant; once the ascorbic acid is fully oxidized, a rapid prooxidant effect is observed; and the ascorbic acid breakdown products responsible for the prooxidant effect have not yet been identified.
Defining the ascorbic acid crossover from anti-oxidant to pro-oxidant in a model wine matrix containing (+)-catechin.
Bradshaw,-M-P; Cheynier,-V; Scollary,-G-R; Prenzler,-P-D
Journal-of-Agricultural-and-Food-Chemistry. 2003; 51(14): 4126-4132 ; 26 ref.
The role of ascorbic acid and its degradation products on the oxidative browning of (+)-catechin was investigated. Using varying concn. of ascorbic acid (200-1000 mg/l) in a model white wine base, it was shown that there were at least 2 distinct steps in the oxidation of (+)-catechin. The 1st step involved the formation of species that absorb in the visible region of the spectrum, while the 2nd step generated species of less or no absorbance in the visible region. The 1st step reached an absorbance max. when ascorbic acid was completely oxidized. In wine base solutions containing both ascorbic acid and (+)-catechin, the lag period prior to the onset of (+)-catechin oxidation was dependent on the concn. of ascorbic acid. It was also observed that the end of the lag period corresponded to the complete oxidation of ascorbic acid. Xanthylium cations were identified as a species responsible for the increase in absorbance at 440 nm post lag period.
