The majority of this content was originally published in Aust. NZ Grapegrower & Winemaker, March 2022 – Issue 698. Introduction Affinity Labs has recently changed the way smoke panel analysis results are reported for Australian customers. Apart from numerical results, reports now include graphs showing where the results sit compared to levels typically present in

Introduction Research at the AWRI and other research organisations has demonstrated that phenolic compounds such as guaiacol, 4 methylguaiacol, cresol and syringol contribute to off-flavours and aromas in wine made from grapes that have been exposed smoke. These volatile phenols can also bind to sugars within grape berries to form phenolic glycosides, which also contribute

Introduction Research at the AWRI and other research organisations has demonstrated that phenolic compounds such as guaiacol, 4-methylguaiacol, cresol and syringol and their glyconjugates (glycosides) contribute to off-flavours and aromas in wines made from grapes that have been exposed to smoke and act as reliable markers of smoke exposure. The full list of compounds analysed

Affinity Labs main testing laboratory is located in Adelaide, South Australia. Importing plant material for laboratory analysis or research purposes is regulated in our state under the Plant Health Act 2009 and the South Australian Plant Quarantine Standard. Our laboratory is a CA12 Accredited laboratory within South Australia which allows us to receive diagnostic plant

Colour of red grapes – Modified Somers The principle of this spectroscopic analysis is based on the methods of Somers and Evans. The Somers colour assay was modified to allow the standardisation of pH concentrations of grape samples in a simple one-step dilution with a buffer solution, thus removing inconsistencies between grape matrices and providing

Ethyl carbamate and urethane is formed during the production of wine resulting from the reaction between urea or other related precursors and ethanol. Urea is derived largely from the yeast metabolism of arginine, which is an abundant amino acid in grape juice. The rate of production of ethyl carbamate is influenced by the concentration of

The use of fining agents such as Casein, skim milk and egg (whites and albumin) during the production process is commonplace in the beverage industry. The purpose of adding a fining agent preparation is to soften or reduce the astringency and/or bitterness; remove proteins capable of haze formation; or reduce colour by the adsorption and

4-ethylphenol and 4-ethylguaiacol are products of metabolism by Brettanomyces yeast. 4-ethylphenol is responsible for the ‘sweaty saddle/band-aid’ aroma of red wines when present in high concentration, and is generally regarded as detrimental to wine quality. Analysis of wine in barrels will determine whether this compound has been formed in high concentration during maturation and may

Phthalates are widely used as additives (plasticisers) in the production of plastic materials, such as PVC, and act to soften the materials to increase its processability, flexibility and extensibility. They are also added to paints, varnishes and rubbers as well as to certain food packaging materials. Phthalates are not chemically bound to the materials they

Botrytis can oxidise glucose in grapes to produce gluconic acid. As gluconic acid is not utilised by yeast or bacteria it is sometimes used as an indicator of Botrytis infection. Gluconic acid is present at low levels in musts and in wines derived from a usual harvest at levels not exceeding 200 – 300 mg/L.